Understanding Cold Water Immersion: Benefits, Risks, and Safety Protocols - Full Transcript

00:00Professor Mike Tipton thank you very Professor Mike Tipton thank you very much for joining us today it's a much for joining us today it's a much for joining us today it's a pleasure nice to be with you Greg pleasure nice to be with you Greg pleasure nice to be with you Greg already today we've had some technical already today we've had some technical already today we've had some technical issues but we actually recorded a issues but we actually recorded a issues but we actually recorded a podcast back in July that was lost podcast back in July that was lost podcast back in July that was lost forever due to some podcast demons so I forever due to some podcast demons so I forever due to some podcast demons so I really appreciate you spending some of really appreciate you spending some of really appreciate you spending some of your valuable time with us again here your valuable time with us again here your valuable time with us again here today and I don't want to just recreate today and I don't want to just recreate today and I don't want to just recreate the episode that we recorded back then the episode that we recorded back then the episode that we recorded back then but I'd like to start on the same note but I'd like to start on the same note but I'd like to start on the same note which is by saying thank you to you which is by saying thank you to you which is by saying thank you to you because you might not know this but I because you might not know this but I because you might not know this but I lost my then best friend to Drowning lost my then best friend to Drowning lost my then best friend to Drowning when I was four and I know a lot of the when I was four and I know a lot of the when I was four and I know a lot of the work that you've done has saved lives work that you've done has saved lives work that you've done has saved lives and it's difficult to quantify how many and it's difficult to quantify how many and it's difficult to quantify how many lives it has saved but I really lives it has saved but I really lives it has saved but I really appreciate the work that you've done and appreciate the work that you've done and appreciate the work that you've done and I'm honored to have you here today thank I'm honored to have you here today thank I'm honored to have you here today thank you Greg I'm sorry about your friend you Greg I'm sorry about your friend you Greg I'm sorry about your friend obviously um but sadly it's not an obviously um but sadly it's not an obviously um but sadly it's not an uncommon experience and uncommon experience and uncommon experience and um people sometimes forget that there's um people sometimes forget that there's um people sometimes forget that there's obviously a casualty in these incidents

01:00obviously a casualty in these incidents obviously a casualty in these incidents but there's a an awful lot of other but there's a an awful lot of other but there's a an awful lot of other people as well who get um impacted and people as well who get um impacted and people as well who get um impacted and affected by these uh events so it has affected by these uh events so it has affected by these uh events so it has been the drowning statistics which are been the drowning statistics which are been the drowning statistics which are are not great a thousand people a day are not great a thousand people a day are not great a thousand people a day around the world one person every 30 around the world one person every 30 around the world one person every 30 hours in the UK a child a week has been hours in the UK a child a week has been hours in the UK a child a week has been the major driver to what we do let's the major driver to what we do let's the major driver to what we do let's start with the effects of cold exposure start with the effects of cold exposure start with the effects of cold exposure on different parts of the human body and on different parts of the human body and on different parts of the human body and from reading your work I know that the from reading your work I know that the from reading your work I know that the Thermon neutral temperature of water is Thermon neutral temperature of water is Thermon neutral temperature of water is about 35° C and I've also seen and heard about 35° C and I've also seen and heard about 35° C and I've also seen and heard you say that we can Define cold water as you say that we can Define cold water as you say that we can Define cold water as anything below about 15° C so we'll use anything below about 15° C so we'll use anything below about 15° C so we'll use that number today but if we start with that number today but if we start with that number today but if we start with cardiovascular health then it might be cardiovascular health then it might be cardiovascular health then it might be helpful to give a relevant context so helpful to give a relevant context so helpful to give a relevant context so let's use the example of a healthy 35y let's use the example of a healthy 35y let's use the example of a healthy 35y old person who spends a total of 3 old person who spends a total of 3 old person who spends a total of 3 minutes moving in 12° C water and I

02:00minutes moving in 12° C water and I minutes moving in 12° C water and I choose 12° for a couple of reasons one choose 12° for a couple of reasons one choose 12° for a couple of reasons one relates to autonomic conflict which will relates to autonomic conflict which will relates to autonomic conflict which will come to later but another is that that's come to later but another is that that's come to later but another is that that's around the average water temperature around the average water temperature around the average water temperature around the UK so if we take this person around the UK so if we take this person around the UK so if we take this person and assume that on entry into the water and assume that on entry into the water and assume that on entry into the water they've jumped in and immersed the head they've jumped in and immersed the head they've jumped in and immersed the head in the in the in the water you water you water you term this initial response that people term this initial response that people term this initial response that people have to entry into cold water the cold have to entry into cold water the cold have to entry into cold water the cold shock response and have done a lot to shock response and have done a lot to shock response and have done a lot to unveil its underlying unveil its underlying unveil its underlying physiology so before we get to autonomic physiology so before we get to autonomic physiology so before we get to autonomic conflict I wonder if you could highlight conflict I wonder if you could highlight conflict I wonder if you could highlight what the cold shock response is yeah what the cold shock response is yeah what the cold shock response is yeah sure um when when we started sure um when when we started sure um when when we started um in the last century about 40 years um in the last century about 40 years um in the last century about 40 years ago researching at the time the ago researching at the time the ago researching at the time the predominant uh problem associated with predominant uh problem associated with predominant uh problem associated with cold water was thought to be hypothermia cold water was thought to be hypothermia cold water was thought to be hypothermia which had started with

03:00which had started with which had started with the Titanic and had been perpetuated the Titanic and had been perpetuated the Titanic and had been perpetuated through the second world war with people through the second world war with people through the second world war with people dying hanging on to rafts Etc um but dying hanging on to rafts Etc um but dying hanging on to rafts Etc um but there was um a a very important report there was um a a very important report there was um a a very important report published in 1977 by the home office published in 1977 by the home office published in 1977 by the home office that showed that showed that showed that about 2third of those that died that about 2third of those that died that about 2third of those that died died within a few feet of safe refuge died within a few feet of safe refuge died within a few feet of safe refuge and about two-thirds were regarded as and about two-thirds were regarded as and about two-thirds were regarded as good swimmers and that obviously doesn't good swimmers and that obviously doesn't good swimmers and that obviously doesn't point to a protracted period of point to a protracted period of point to a protracted period of immersion necessary to become immersion necessary to become immersion necessary to become hypothermic um even in the coldest water hypothermic um even in the coldest water hypothermic um even in the coldest water and with somebody who's near naked they and with somebody who's near naked they and with somebody who's near naked they won't become hypothermic unless than 30 won't become hypothermic unless than 30 won't become hypothermic unless than 30 minutes so it was clear that something minutes so it was clear that something minutes so it was clear that something um else was claiming these lives in a um else was claiming these lives in a um else was claiming these lives in a very short period of time long before very short period of time long before very short period of time long before hypothermia could come about and we'd hypothermia could come about and we'd hypothermia could come about and we'd done some studies in the lab and um I done some studies in the lab and um I done some studies in the lab and um I was working at the time um with a great was working at the time um with a great was working at the time um with a great friend excellent scientist called Frank friend excellent scientist called Frank friend excellent scientist called Frank golden and we looked at the initial

04:00golden and we looked at the initial golden and we looked at the initial responses to cold water immersion I responses to cold water immersion I responses to cold water immersion I remember sitting in an office with him remember sitting in an office with him remember sitting in an office with him trying to decide what we would call trying to decide what we would call trying to decide what we would call these responses and we call them cold these responses and we call them cold these responses and we call them cold shock because they were a shocking shock because they were a shocking shock because they were a shocking experience as opposed to a medical experience as opposed to a medical experience as opposed to a medical definition of shock because as many definition of shock because as many definition of shock because as many people who are listening to this podcast people who are listening to this podcast people who are listening to this podcast will know when you first go into cold will know when you first go into cold will know when you first go into cold water you gasp a bit you hyperventilate water you gasp a bit you hyperventilate water you gasp a bit you hyperventilate there's an increase in your heart rate there's an increase in your heart rate there's an increase in your heart rate increase in your cardiac output you shut increase in your cardiac output you shut increase in your cardiac output you shut down your peripheral blood vessels um in down your peripheral blood vessels um in down your peripheral blood vessels um in in an attempt to conserve body heat and in an attempt to conserve body heat and in an attempt to conserve body heat and that puts up blood pressure and so that puts up blood pressure and so that puts up blood pressure and so that's what we call cold shock and when that's what we call cold shock and when that's what we call cold shock and when you see it um in its full effect in full you see it um in its full effect in full you see it um in its full effect in full magnitude that gasp is 2 to three lers magnitude that gasp is 2 to three lers magnitude that gasp is 2 to three lers um it is Then followed by uncontrollable um it is Then followed by uncontrollable um it is Then followed by uncontrollable hyperventilation that can go on for a hyperventilation that can go on for a hyperventilation that can go on for a minute and you've see a very significant minute and you've see a very significant minute and you've see a very significant increase in blood pressure the gasp is increase in blood pressure the gasp is increase in blood pressure the gasp is as I say 2 to 3 l the lethal dose of as I say 2 to 3 l the lethal dose of as I say 2 to 3 l the lethal dose of salt water into the lung is one and a salt water into the lung is one and a salt water into the lung is one and a half so you fall into salt salt water

05:00half so you fall into salt salt water half so you fall into salt salt water you've lost control of your breathing you've lost control of your breathing you've lost control of your breathing you're gasping and you're it's really you're gasping and you're it's really you're gasping and you're it's really it's luck whether or not you're under it's luck whether or not you're under it's luck whether or not you're under the water or wave is breaking over your the water or wave is breaking over your the water or wave is breaking over your face whilst that gasping and face whilst that gasping and face whilst that gasping and hyperventilation are going on so this is hyperventilation are going on so this is hyperventilation are going on so this is a big a big a big cardiorespiratory cardiovascular cardiorespiratory cardiovascular cardiorespiratory cardiovascular response and it's driven by the response and it's driven by the response and it's driven by the sympathetic nervous system it's part of sympathetic nervous system it's part of sympathetic nervous system it's part of the fight or flight response it's just the fight or flight response it's just the fight or flight response it's just completely inappropriate in water um not completely inappropriate in water um not completely inappropriate in water um not so bad on land when it's preparing you so bad on land when it's preparing you so bad on land when it's preparing you to run away or fight but in water to run away or fight but in water to run away or fight but in water particularly where the airway is under particularly where the airway is under particularly where the airway is under threat it's the leading cause of death threat it's the leading cause of death threat it's the leading cause of death on imersion as a precursor to drowning on imersion as a precursor to drowning on imersion as a precursor to drowning and cardiac problems so um it's not and cardiac problems so um it's not and cardiac problems so um it's not hypothermia it's cold shock that's hypothermia it's cold shock that's hypothermia it's cold shock that's killing 60% of those who fall into cold killing 60% of those who fall into cold killing 60% of those who fall into cold water so turning now to autonomic water so turning now to autonomic water so turning now to autonomic conflicts which is a term that I believe conflicts which is a term that I believe conflicts which is a term that I believe you coined cold water immersion strongly you coined cold water immersion strongly you coined cold water immersion strongly increases activity in the sympathetic increases activity in the sympathetic increases activity in the sympathetic branch of the autonomic nervous system branch of the autonomic nervous system branch of the autonomic nervous system but submerging the face in water and

06:00but submerging the face in water and but submerging the face in water and holding the breath increase activity in holding the breath increase activity in holding the breath increase activity in the parasympathetic branch of that the parasympathetic branch of that the parasympathetic branch of that system this is known as the diving system this is known as the diving system this is known as the diving response and so there's this unusual response and so there's this unusual response and so there's this unusual situation in which you've concurrently situation in which you've concurrently situation in which you've concurrently got high activation of both of those got high activation of both of those got high activation of both of those branches producing kind of autonomic branches producing kind of autonomic branches producing kind of autonomic conflict particularly when the breath conflict particularly when the breath conflict particularly when the breath hold ceases can you tell us about how hold ceases can you tell us about how hold ceases can you tell us about how this might affect acute this might affect acute this might affect acute cardiovascular health and maybe lead to cardiovascular health and maybe lead to cardiovascular health and maybe lead to some cardiovascular events including the some cardiovascular events including the some cardiovascular events including the surprisingly high frequency of a surprisingly high frequency of a surprisingly high frequency of a rhythmus that occur even in relatively rhythmus that occur even in relatively rhythmus that occur even in relatively young healthy people yeah sure um yes we young healthy people yeah sure um yes we young healthy people yeah sure um yes we did we did name autonomic conflict in did we did name autonomic conflict in did we did name autonomic conflict in fact fact fact probably um my major came to fame is probably um my major came to fame is probably um my major came to fame is being able to name things I should have being able to name things I should have being able to name things I should have been a newspaper headline writer rather been a newspaper headline writer rather been a newspaper headline writer rather than a scientist it's a cold shock than a scientist it's a cold shock than a scientist it's a cold shock autonomic conflict and all these other autonomic conflict and all these other autonomic conflict and all these other so yeah you get a you get a cold shock so yeah you get a you get a cold shock so yeah you get a you get a cold shock response which we've discussed when the

07:00response which we've discussed when the response which we've discussed when the face goes in uh you've got the Opthalmic face goes in uh you've got the Opthalmic face goes in uh you've got the Opthalmic division of the trigeminal nerve and division of the trigeminal nerve and division of the trigeminal nerve and you're stimulating um cardiac vagal you're stimulating um cardiac vagal you're stimulating um cardiac vagal motor neurons which are slowing the motor neurons which are slowing the motor neurons which are slowing the heart so you've got two conflicting heart so you've got two conflicting heart so you've got two conflicting inputs one trying to accelerate the inputs one trying to accelerate the inputs one trying to accelerate the heart the cold shock sympathetic heart the cold shock sympathetic heart the cold shock sympathetic response and one trying to slow it the response and one trying to slow it the response and one trying to slow it the vagal cardiac motor neurons vagal cardiac motor neurons vagal cardiac motor neurons parasympathetic response which which is parasympathetic response which which is parasympathetic response which which is why we call it autonomic conflict why we call it autonomic conflict why we call it autonomic conflict because a conflict between the two because a conflict between the two because a conflict between the two branches of the autonomic nervous system branches of the autonomic nervous system branches of the autonomic nervous system and and and um if you take somebody and you immerse um if you take somebody and you immerse um if you take somebody and you immerse them into the water to the shoulders them into the water to the shoulders them into the water to the shoulders you'll just get a cold shock response um you'll just get a cold shock response um you'll just get a cold shock response um driven by Cold receptors .18 millim driven by Cold receptors .18 millim driven by Cold receptors .18 millim below the surface of the below the surface of the below the surface of the skin the dynamic response of those skin the dynamic response of those skin the dynamic response of those receptors drives directly the receptors drives directly the receptors drives directly the respiratory Center causes the Gasping respiratory Center causes the Gasping respiratory Center causes the Gasping and the hyperventilation that Peaks and the hyperventilation that Peaks and the hyperventilation that Peaks somewhere between the water temperature somewhere between the water temperature somewhere between the water temperature of 10 and 15° C if you go below that the of 10 and 15° C if you go below that the of 10 and 15° C if you go below that the physiological response doesn't get any physiological response doesn't get any physiological response doesn't get any greater it just just feels colder and

08:00greater it just just feels colder and greater it just just feels colder and colder and then becomes painfully cold colder and then becomes painfully cold colder and then becomes painfully cold um so that's all you're going to see if um so that's all you're going to see if um so that's all you're going to see if you just put the face into a bowl of you just put the face into a bowl of you just put the face into a bowl of cold water which is a classic student cold water which is a classic student cold water which is a classic student practical to demonstrate um the diving practical to demonstrate um the diving practical to demonstrate um the diving response you'll see a bradic cardia um response you'll see a bradic cardia um response you'll see a bradic cardia um it also includes a redistribution of it also includes a redistribution of it also includes a redistribution of blood flow such that blood pressure blood flow such that blood pressure blood flow such that blood pressure stays the same it doesn't increase as it stays the same it doesn't increase as it stays the same it doesn't increase as it does in cold chalk response and you'll does in cold chalk response and you'll does in cold chalk response and you'll see an apnea and it's the response which see an apnea and it's the response which see an apnea and it's the response which allows diving mammals to to die for allows diving mammals to to die for allows diving mammals to to die for protracted periods is an oxygen protracted periods is an oxygen protracted periods is an oxygen conserving conserving conserving response um now um if you go under the response um now um if you go under the response um now um if you go under the water and or you dive into the water or water and or you dive into the water or water and or you dive into the water or you're swimming in the water uh then you're swimming in the water uh then you're swimming in the water uh then you'll have the opportunity to stimulate you'll have the opportunity to stimulate you'll have the opportunity to stimulate both branches of that autonomic nervous both branches of that autonomic nervous both branches of that autonomic nervous system now head out immersion will system now head out immersion will system now head out immersion will normally in young fit healthy normally in young fit healthy normally in young fit healthy individuals see um an arhythmia in maybe individuals see um an arhythmia in maybe individuals see um an arhythmia in maybe one in a 100 immersions and it'll be one one in a 100 immersions and it'll be one one in a 100 immersions and it'll be one of often you know of no

09:00of often you know of no of often you know of no consequence if you um go under the water consequence if you um go under the water consequence if you um go under the water or you put the face in the water and you or you put the face in the water and you or you put the face in the water and you do a protracted breath hold um in that do a protracted breath hold um in that do a protracted breath hold um in that situation you'll see up to 80% of situation you'll see up to 80% of situation you'll see up to 80% of immersions result in some form of of immersions result in some form of of immersions result in some form of of arhythmia it may well be just um a arhythmia it may well be just um a arhythmia it may well be just um a slowing and an acceleration of the heart slowing and an acceleration of the heart slowing and an acceleration of the heart um or but it might be a super um or but it might be a super um or but it might be a super ventricular or a ventricular ventricular or a ventricular ventricular or a ventricular arhythmia and they normally occur within arhythmia and they normally occur within arhythmia and they normally occur within 10 seconds of breaking of the the 10 seconds of breaking of the the 10 seconds of breaking of the the breathhold so the breath hold in is is breathhold so the breath hold in is is breathhold so the breath hold in is is in itself um AR rhythmogenic now um so in itself um AR rhythmogenic now um so in itself um AR rhythmogenic now um so we've done studies on things like people we've done studies on things like people we've done studies on things like people doing helicopter underwater Escape doing helicopter underwater Escape doing helicopter underwater Escape training to fly offshore um which is training to fly offshore um which is training to fly offshore um which is what they have to do and seen 25% of what they have to do and seen 25% of what they have to do and seen 25% of them during the period it takes them them during the period it takes them them during the period it takes them when they the helicopter inverts and when they the helicopter inverts and when they the helicopter inverts and then they have to come out and get to then they have to come out and get to then they have to come out and get to the surface not very long 10 15 seconds the surface not very long 10 15 seconds the surface not very long 10 15 seconds about 25% sh on arhythmia um normally about 25% sh on arhythmia um normally about 25% sh on arhythmia um normally that's all you see and it doesn't that's all you see and it doesn't that's all you see and it doesn't descend in to anything more critical but

10:00descend in to anything more critical but descend in to anything more critical but if you have predisposing factors such as if you have predisposing factors such as if you have predisposing factors such as um Long QT syndrome uh cardiovascular um Long QT syndrome uh cardiovascular um Long QT syndrome uh cardiovascular disease heart disease uh there's a disease heart disease uh there's a disease heart disease uh there's a there's a an increased chance that that there's a an increased chance that that there's a an increased chance that that arithm magenic stimulus of autonomic arithm magenic stimulus of autonomic arithm magenic stimulus of autonomic conflict will then descend into conflict will then descend into conflict will then descend into something more significant and we've something more significant and we've something more significant and we've done work with my friend and colleague done work with my friend and colleague done work with my friend and colleague Mike shat Professor Mike shat at Kings Mike shat Professor Mike shat at Kings Mike shat Professor Mike shat at Kings who's a cellular who's a cellular who's a cellular cardiologist and shown that you can um cardiologist and shown that you can um cardiologist and shown that you can um provoke these arrhythmias in isolated provoke these arrhythmias in isolated provoke these arrhythmias in isolated Hearts uh and the particular arhythmia Hearts uh and the particular arhythmia Hearts uh and the particular arhythmia that descended into to was torsa de so that descended into to was torsa de so that descended into to was torsa de so um we think that um despite the fact um we think that um despite the fact um we think that um despite the fact that drowning is an a large problem on that drowning is an a large problem on that drowning is an a large problem on immersion obviously on cold water immersion obviously on cold water immersion obviously on cold water immersion and does account for the immersion and does account for the immersion and does account for the majority of deaths probably the deaths majority of deaths probably the deaths majority of deaths probably the deaths from cardiac problems are underestimated

11:00um and the reason is that this is an um and the reason is that this is an electrical disturbance of the heart that electrical disturbance of the heart that electrical disturbance of the heart that may incapacitate you may cause you then may incapacitate you may cause you then may incapacitate you may cause you then during agonal gasping to aspirate water during agonal gasping to aspirate water during agonal gasping to aspirate water and it looks very like a postmortem like and it looks very like a postmortem like and it looks very like a postmortem like a drowning because you won't see a drowning because you won't see a drowning because you won't see anything wrong with the heart it's not anything wrong with the heart it's not anything wrong with the heart it's not like there's been a clot or something like there's been a clot or something like there's been a clot or something obvious that you can see anatomically obvious that you can see anatomically obvious that you can see anatomically wrong with the heart um but we're seeing wrong with the heart um but we're seeing wrong with the heart um but we're seeing we've seen enough of these in young fit we've seen enough of these in young fit we've seen enough of these in young fit healthy people these arrhythmias to know healthy people these arrhythmias to know healthy people these arrhythmias to know that in people who are less fit or have that in people who are less fit or have that in people who are less fit or have predisposing comorbidities that is it's predisposing comorbidities that is it's predisposing comorbidities that is it's probably a significant cause of problems probably a significant cause of problems probably a significant cause of problems on on on immersion and I think I've heard you say immersion and I think I've heard you say immersion and I think I've heard you say that you can reliably induce an that you can reliably induce an that you can reliably induce an arhythmia an healthy young person arhythmia an healthy young person arhythmia an healthy young person combining a breath hold with head combining a breath hold with head combining a breath hold with head included cold water immersion roughly included cold water immersion roughly included cold water immersion roughly 83% of the time is that right yeah 83% of the time is that right yeah 83% of the time is that right yeah that's right yeah yes as I say it goes that's right yeah yes as I say it goes that's right yeah yes as I say it goes It goes above 80% in that and that's It goes above 80% in that and that's It goes above 80% in that and that's young fit health individuals individuals

12:00young fit health individuals individuals young fit health individuals individuals who've been screened had a 12 lead um who've been screened had a 12 lead um who've been screened had a 12 lead um ECG to check that they've got a normal ECG to check that they've got a normal ECG to check that they've got a normal heart yeah well the most recent work heart yeah well the most recent work heart yeah well the most recent work which is yet to be published but has which is yet to be published but has which is yet to be published but has been done by um a a colleague and and been done by um a a colleague and and been done by um a a colleague and and PhD student Dr Paddy Morgan who's an PhD student Dr Paddy Morgan who's an PhD student Dr Paddy Morgan who's an entist um is we're moving towards entist um is we're moving towards entist um is we're moving towards actually being able to predict the actually being able to predict the actually being able to predict the people who are most likely to show the people who are most likely to show the people who are most likely to show the arithm is on whole body immersion just arithm is on whole body immersion just arithm is on whole body immersion just by what happens during a face immersion by what happens during a face immersion by what happens during a face immersion so we're moving towards being able to so we're moving towards being able to so we're moving towards being able to screen individuals who are more likely screen individuals who are more likely screen individuals who are more likely to have during whole body immersion um to have during whole body immersion um to have during whole body immersion um and an arhythmia so that's an exciting and an arhythmia so that's an exciting and an arhythmia so that's an exciting development but it's fairly hot off the development but it's fairly hot off the development but it's fairly hot off the press and has not yet been peer-reviewed press and has not yet been peer-reviewed press and has not yet been peer-reviewed or published interesting and I'll or published interesting and I'll or published interesting and I'll combine two questions in one here one is combine two questions in one here one is combine two questions in one here one is can you mention anything about what the can you mention anything about what the can you mention anything about what the predictive variables are for example do predictive variables are for example do predictive variables are for example do you see more pronounced bradicardia and you see more pronounced bradicardia and you see more pronounced bradicardia and people who are more likely to experience people who are more likely to experience people who are more likely to experience an an an arhythmia and then second arhythmia and then second arhythmia and then second you spoke earlier about how the strong

13:00you spoke earlier about how the strong you spoke earlier about how the strong increase in sympathetic activity on cold increase in sympathetic activity on cold increase in sympathetic activity on cold immersion is inappropriate for us immersion is inappropriate for us immersion is inappropriate for us nowadays is it a vesage of our ancestors nowadays is it a vesage of our ancestors nowadays is it a vesage of our ancestors the fact that we've evolved from simpler the fact that we've evolved from simpler the fact that we've evolved from simpler organisms in which that type of response organisms in which that type of response organisms in which that type of response might have been adaptive but nowadays in might have been adaptive but nowadays in might have been adaptive but nowadays in our human physiology it's entirely our human physiology it's entirely our human physiology it's entirely inappropriate so um with regard to the inappropriate so um with regard to the inappropriate so um with regard to the predictive nature the arrhythmias tend predictive nature the arrhythmias tend predictive nature the arrhythmias tend to occur when you switch from a to occur when you switch from a to occur when you switch from a bradicardia to a tachicardia so when you bradicardia to a tachicardia so when you bradicardia to a tachicardia so when you actually look at the ECG of somebody who actually look at the ECG of somebody who actually look at the ECG of somebody who has been under the water comes to the has been under the water comes to the has been under the water comes to the surface takes a their first breath in or surface takes a their first breath in or surface takes a their first breath in or breath starts to rebreathe through their breath starts to rebreathe through their breath starts to rebreathe through their snorkel you you see um ECG shows a snorkel you you see um ECG shows a snorkel you you see um ECG shows a period of period of period of tachicardia and then a period of tachicardia and then a period of tachicardia and then a period of bradicardia then a period of tachicardia bradicardia then a period of tachicardia bradicardia then a period of tachicardia and this lasts for about a minute where and this lasts for about a minute where and this lasts for about a minute where the heart is switching between this sort

14:00the heart is switching between this sort the heart is switching between this sort of sympathetic driven Rhythm and a of sympathetic driven Rhythm and a of sympathetic driven Rhythm and a parasympathetic driven Rhythm and where parasympathetic driven Rhythm and where parasympathetic driven Rhythm and where we see um the change in that rhythm is we see um the change in that rhythm is we see um the change in that rhythm is where we're most likely going to see the where we're most likely going to see the where we're most likely going to see the um ventricular super ventricular um ventricular super ventricular um ventricular super ventricular arhythmia so you've got a dis rythmia arhythmia so you've got a dis rythmia arhythmia so you've got a dis rythmia going on anyway a sort of wave of going on anyway a sort of wave of going on anyway a sort of wave of tachicardia followed by a wave of tachicardia followed by a wave of tachicardia followed by a wave of bradicardia and that presumably is just bradicardia and that presumably is just bradicardia and that presumably is just you know the two inputs Into the Heart you know the two inputs Into the Heart you know the two inputs Into the Heart taking control one after the other but taking control one after the other but taking control one after the other but where the Rhythm switch um is where where the Rhythm switch um is where where the Rhythm switch um is where you're most likely to see um a an you're most likely to see um a an you're most likely to see um a an ectopic an arhythmia so that's that's if ectopic an arhythmia so that's that's if ectopic an arhythmia so that's that's if you see somebody who's got um that big you see somebody who's got um that big you see somebody who's got um that big variation in in bradicardia tachicardia variation in in bradicardia tachicardia variation in in bradicardia tachicardia post breath holding then they're the post breath holding then they're the post breath holding then they're the people who are most likely to show some people who are most likely to show some people who are most likely to show some kind of arhythmia so that's one way of kind of arhythmia so that's one way of kind of arhythmia so that's one way of looking at it um your other question was looking at it um your other question was looking at it um your other question was about this the the existence of the about this the the existence of the about this the the existence of the sympathetic Drive the sympathetic drive

15:00sympathetic Drive the sympathetic drive sympathetic Drive the sympathetic drive to a threat is normal um but it's normal to a threat is normal um but it's normal to a threat is normal um but it's normal for air so um you know if and for air so um you know if and for air so um you know if and ancestrally you're quite right if we ancestrally you're quite right if we ancestrally you're quite right if we came in into a situation where we had came in into a situation where we had came in into a situation where we had the option to run away or fight it's the the option to run away or fight it's the the option to run away or fight it's the sympathetic system that is um the system sympathetic system that is um the system sympathetic system that is um the system that will prepare you to do that and it that will prepare you to do that and it that will prepare you to do that and it does that by increasing breathing does that by increasing breathing does that by increasing breathing increasing blood flow to the muscles increasing blood flow to the muscles increasing blood flow to the muscles increasing cardiac output so you're increasing cardiac output so you're increasing cardiac output so you're primed to go uh and releasing the stress primed to go uh and releasing the stress primed to go uh and releasing the stress hormones as well the the and that's hormones as well the the and that's hormones as well the the and that's great uh and very useful if you're about great uh and very useful if you're about great uh and very useful if you're about to engage in a 100 meter sprint or to engage in a 100 meter sprint or to engage in a 100 meter sprint or something like that um or a boxing match something like that um or a boxing match something like that um or a boxing match however um if you're in a situation however um if you're in a situation however um if you're in a situation where you are periodically being where you are periodically being where you are periodically being submerged by waves breaking over your submerged by waves breaking over your submerged by waves breaking over your face or you've fallen from a height and face or you've fallen from a height and face or you've fallen from a height and you've gone under the you've gone under the you've gone under the water that response is of no use water that response is of no use water that response is of no use whatsoever it's of it's of you know it's whatsoever it's of it's of you know it's whatsoever it's of it's of you know it's just a good response in a bad situation

16:00just a good response in a bad situation just a good response in a bad situation so it's of no it's little or no use in so it's of no it's little or no use in so it's of no it's little or no use in fact it's probably hazardous fact it's probably hazardous fact it's probably hazardous particularly when compounded by the particularly when compounded by the particularly when compounded by the drive from the afference of the cold drive from the afference of the cold drive from the afference of the cold receptors um so um but it's an receptors um so um but it's an receptors um so um but it's an absolutely normal natural response and absolutely normal natural response and absolutely normal natural response and one of the excuse me one of the one of the excuse me one of the one of the excuse me one of the questions that we spent a bit of time questions that we spent a bit of time questions that we spent a bit of time thinking about was why do 80% of the thinking about was why do 80% of the thinking about was why do 80% of the deaths that occur in triathlons deaths that occur in triathlons deaths that occur in triathlons occur um during the swim phase and all occur um during the swim phase and all occur um during the swim phase and all of those people and this this is up to of those people and this this is up to of those people and this this is up to an including Iron Man so these people an including Iron Man so these people an including Iron Man so these people are not untrained they're young fit are not untrained they're young fit are not untrained they're young fit healthy individuals or they're old fit healthy individuals or they're old fit healthy individuals or they're old fit healthy individuals and um they've done healthy individuals and um they've done healthy individuals and um they've done a lots of training and they've not had a lots of training and they've not had a lots of training and they've not had these problems during training so what these problems during training so what these problems during training so what is what's different about a race that is what's different about a race that is what's different about a race that increases the likelihood of um a problem increases the likelihood of um a problem increases the likelihood of um a problem a cardiac problem and most of these a cardiac problem and most of these a cardiac problem and most of these deaths are cardiac in accidentally and

17:00deaths are cardiac in accidentally and deaths are cardiac in accidentally and it's probably in part the sympathetic it's probably in part the sympathetic it's probably in part the sympathetic overdrive that comes from the fact that overdrive that comes from the fact that overdrive that comes from the fact that you're in um an event and anyone um of you're in um an event and anyone um of you're in um an event and anyone um of your listeners that's been involved in your listeners that's been involved in your listeners that's been involved in the mass start in a triathlon will know the mass start in a triathlon will know the mass start in a triathlon will know that it's a fairly um aggravating and that it's a fairly um aggravating and that it's a fairly um aggravating and exciting experience you the first 400 exciting experience you the first 400 exciting experience you the first 400 meters which is where most of these meters which is where most of these meters which is where most of these deaths occur just involves pulling on deaths occur just involves pulling on deaths occur just involves pulling on neoprene and shouting at people uh but neoprene and shouting at people uh but neoprene and shouting at people uh but the other thing that happens is when you the other thing that happens is when you the other thing that happens is when you turn to breathe because there's so many turn to breathe because there's so many turn to breathe because there's so many people people people um accumulated together at the start on um accumulated together at the start on um accumulated together at the start on the mass start sometimes you can't take the mass start sometimes you can't take the mass start sometimes you can't take a breath you because you've got a plume a breath you because you've got a plume a breath you because you've got a plume of water over your face so you end up of water over your face so you end up of water over your face so you end up extending your breath hold time now that extending your breath hold time now that extending your breath hold time now that sympathetic overdrive that face sympathetic overdrive that face sympathetic overdrive that face immersion that extended breath hold is immersion that extended breath hold is immersion that extended breath hold is exactly the combination of factors you exactly the combination of factors you exactly the combination of factors you need to induce autonomic conflict um and need to induce autonomic conflict um and need to induce autonomic conflict um and so you know what this at one level is of so you know what this at one level is of so you know what this at one level is of you know tremendous academic interest you know tremendous academic interest you know tremendous academic interest they also have some pra I mean that's they also have some pra I mean that's they also have some pra I mean that's the nice thing about what we do it has the nice thing about what we do it has the nice thing about what we do it has you know we're applied scientists so we

18:00you know we're applied scientists so we you know we're applied scientists so we take an understanding of the mechanistic take an understanding of the mechanistic take an understanding of the mechanistic physiology and try to apply it and you physiology and try to apply it and you physiology and try to apply it and you say okay well if I'm running a a mass say okay well if I'm running a a mass say okay well if I'm running a a mass participation swimming event I'm going participation swimming event I'm going participation swimming event I'm going to make sure we have waves where people to make sure we have waves where people to make sure we have waves where people are separated where they don't end up are separated where they don't end up are separated where they don't end up clambering over each other don't end up clambering over each other don't end up clambering over each other don't end up having to extend their breathhold we're having to extend their breathhold we're having to extend their breathhold we're going to swim them a certain distance going to swim them a certain distance going to swim them a certain distance before we turn them so we don't have before we turn them so we don't have before we turn them so we don't have coming together and boys and things like coming together and boys and things like coming together and boys and things like that so yeah there we are I mean it's a that so yeah there we are I mean it's a that so yeah there we are I mean it's a it's an it's an interesting it's an it's an it's an interesting it's an it's an it's an interesting it's an interesting um interesting um interesting um combination so staggered starts and combination so staggered starts and combination so staggered starts and appropriate course planning can make a appropriate course planning can make a appropriate course planning can make a difference oh absolutely and um you know difference oh absolutely and um you know difference oh absolutely and um you know as I say and also as best you can as I say and also as best you can as I say and also as best you can watching out for people who have watching out for people who have watching out for people who have channelopathies atherosclerosis myidal channelopathies atherosclerosis myidal channelopathies atherosclerosis myidal hypertrophy esic heart disease um Long hypertrophy esic heart disease um Long hypertrophy esic heart disease um Long QT syndrome or acquired Long QT Syndrome QT syndrome or acquired Long QT Syndrome QT syndrome or acquired Long QT Syndrome from from the drugs they're taking some from from the drugs they're taking some from from the drugs they're taking some drugs antihistamines for example can

19:00drugs antihistamines for example can drugs antihistamines for example can extend the QT interval and make you more extend the QT interval and make you more extend the QT interval and make you more likely that the make it more likely that likely that the make it more likely that likely that the make it more likely that the arhythmia you um get from autonomic the arhythmia you um get from autonomic the arhythmia you um get from autonomic conflict will descend into something conflict will descend into something conflict will descend into something more more serious they're the more more serious they're the more more serious they're the predisposing factors which is predisposing factors which is predisposing factors which is interesting in the light of the fact interesting in the light of the fact interesting in the light of the fact that a lot of those triathlons probably that a lot of those triathlons probably that a lot of those triathlons probably take place during the summer a time of take place during the summer a time of take place during the summer a time of year when people are more likely to take year when people are more likely to take year when people are more likely to take antihistamines to manage hay fever but antihistamines to manage hay fever but antihistamines to manage hay fever but Mike I know you've done some work Mike I know you've done some work Mike I know you've done some work oh sorry there's a bit of a delay I oh sorry there's a bit of a delay I oh sorry there's a bit of a delay I apologize I was just going to say and apologize I was just going to say and apologize I was just going to say and even though even though it's the summer even though even though it's the summer even though even though it's the summer um in many parts of the world the summer um in many parts of the world the summer um in many parts of the world the summer still will have water temperatures that still will have water temperatures that still will have water temperatures that are cold enough to evoke cold shock um are cold enough to evoke cold shock um are cold enough to evoke cold shock um which we see in terms of an increase in which we see in terms of an increase in which we see in terms of an increase in respiration uh water temperatures around respiration uh water temperatures around respiration uh water temperatures around 25 I mean it's easily suppressed then 25 I mean it's easily suppressed then 25 I mean it's easily suppressed then when you go into a swimming pool you when you go into a swimming pool you when you go into a swimming pool you might have a little like this but it's might have a little like this but it's might have a little like this but it's easily suppressed as the water easily suppressed as the water easily suppressed as the water temperature Falls it gets it gets a more temperature Falls it gets it gets a more temperature Falls it gets it gets a more much more powerful response but of much more powerful response but of much more powerful response but of course even if you're in water and course even if you're in water and course even if you're in water and wearing a wet suit the sympathetic drive

20:00wearing a wet suit the sympathetic drive wearing a wet suit the sympathetic drive from cold shock is then often replaced from cold shock is then often replaced from cold shock is then often replaced by the sympathetic drive from the fact by the sympathetic drive from the fact by the sympathetic drive from the fact that you're at the start of a that you're at the start of a that you're at the start of a competition yeah absolutely and I know competition yeah absolutely and I know competition yeah absolutely and I know you've done some work showing that cold you've done some work showing that cold you've done some work showing that cold acclamation can quite quickly and acclamation can quite quickly and acclamation can quite quickly and reliably reduce the cold shock response reliably reduce the cold shock response reliably reduce the cold shock response can you give an example of what type of can you give an example of what type of can you give an example of what type of protocol would do that yeah sure so um protocol would do that yeah sure so um protocol would do that yeah sure so um because the cold shock response is because the cold shock response is because the cold shock response is evoked by the Dynamic response to the evoked by the Dynamic response to the evoked by the Dynamic response to the cold receptors and it peaks in the first cold receptors and it peaks in the first cold receptors and it peaks in the first 30 seconds and is pretty much 30 seconds and is pretty much 30 seconds and is pretty much disappeared after 3 minutes you only disappeared after 3 minutes you only disappeared after 3 minutes you only need to do repeated short immersions in need to do repeated short immersions in need to do repeated short immersions in order to repeatedly evoke that response order to repeatedly evoke that response order to repeatedly evoke that response and develop it's a true habituation it's and develop it's a true habituation it's and develop it's a true habituation it's a decreased response to a constant a decreased response to a constant a decreased response to a constant stimulus so our standard protocol would stimulus so our standard protocol would stimulus so our standard protocol would be something like 6 3 minute immersions be something like 6 3 minute immersions be something like 6 3 minute immersions in cold water headout immersions and in cold water headout immersions and in cold water headout immersions and over those six immersions you'll see um over those six immersions you'll see um over those six immersions you'll see um roughly a harving of the respiratory and

21:00roughly a harving of the respiratory and roughly a harving of the respiratory and cardiac response to immersion what cardiac response to immersion what cardiac response to immersion what normally happens is the second immersion normally happens is the second immersion normally happens is the second immersion is the worst for people and it's just is the worst for people and it's just is the worst for people and it's just one of the functions of cold water in one of the functions of cold water in one of the functions of cold water in that it's really hard to give people that it's really hard to give people that it's really hard to give people informed consent about water temperature informed consent about water temperature informed consent about water temperature because they immediately translate it because they immediately translate it because they immediately translate it into air temperature so if I say to you into air temperature so if I say to you into air temperature so if I say to you okay we're going to do six three minute okay we're going to do six three minute okay we're going to do six three minute immersions are you happy to do them and immersions are you happy to do them and immersions are you happy to do them and you say well what's the water you say well what's the water you say well what's the water temperature and I say oh it's 12 Dees temperature and I say oh it's 12 Dees temperature and I say oh it's 12 Dees you think oh it's 12° outside that's you think oh it's 12° outside that's you think oh it's 12° outside that's that's not too bad but of course 12° that's not too bad but of course 12° that's not too bad but of course 12° water is a completely different physical water is a completely different physical water is a completely different physical challenge in terms of the physics of the challenge in terms of the physics of the challenge in terms of the physics of the water the cond conductivity and specific water the cond conductivity and specific water the cond conductivity and specific heat to air so normally the first one of heat to air so normally the first one of heat to air so normally the first one of these immersions despite our best these immersions despite our best these immersions despite our best intentions to inform people is something intentions to inform people is something intentions to inform people is something of a surprise and the second one they of a surprise and the second one they of a surprise and the second one they get more anxious about and then after get more anxious about and then after get more anxious about and then after that you start to see a decline in these that you start to see a decline in these that you start to see a decline in these responses um and that decline after six responses um and that decline after six responses um and that decline after six immersions as I say is about a 50%

22:00immersions as I say is about a 50% immersions as I say is about a 50% reduction in the cold shock response reduction in the cold shock response reduction in the cold shock response importantly um your breathing gets back importantly um your breathing gets back importantly um your breathing gets back under control sooner so it's not just a under control sooner so it's not just a under control sooner so it's not just a matter of the ventilatory response it's matter of the ventilatory response it's matter of the ventilatory response it's actually how quickly you can suppress actually how quickly you can suppress actually how quickly you can suppress that respiratory drive and that occurs that respiratory drive and that occurs that respiratory drive and that occurs more quickly and then we've done tests more quickly and then we've done tests more quickly and then we've done tests where we've looked at people 14 months where we've looked at people 14 months where we've looked at people 14 months later and they still have uh 25% later and they still have uh 25% later and they still have uh 25% reduction in the cold chock response so reduction in the cold chock response so reduction in the cold chock response so it's a fairly permanent alteration a it's a fairly permanent alteration a it's a fairly permanent alteration a combination of Psychology and Physiology combination of Psychology and Physiology combination of Psychology and Physiology I suspect and we know that that I suspect and we know that that I suspect and we know that that adaptation occurs somewhere more Central adaptation occurs somewhere more Central adaptation occurs somewhere more Central than the peripheral cold receptors than the peripheral cold receptors than the peripheral cold receptors because if you repeatedly immerse one because if you repeatedly immerse one because if you repeatedly immerse one side of the body to get a cold shock side of the body to get a cold shock side of the body to get a cold shock habituation if you then turn the body habituation if you then turn the body habituation if you then turn the body over and immerse the other side you see over and immerse the other side you see over and immerse the other side you see the same reduction that's in um even the same reduction that's in um even the same reduction that's in um even though you're exposing the side of the though you're exposing the side of the though you're exposing the side of the body that's never been in the cold so body that's never been in the cold so body that's never been in the cold so this is a this is occurring more Central this is a this is occurring more Central this is a this is occurring more Central than the pral cold than the pral cold than the pral cold receptors and if people were interested receptors and if people were interested receptors and if people were interested in cold in cold in cold adaptation then what would be an

23:00adaptation then what would be an adaptation then what would be an appropriate density of those sessions appropriate density of those sessions appropriate density of those sessions would it be spacing six sessions out would it be spacing six sessions out would it be spacing six sessions out over three weeks for example yeah it's a it's a good question example yeah it's a it's a good question to which we don't really know the answer to which we don't really know the answer to which we don't really know the answer um but we've actually done it um for um but we've actually done it um for um but we've actually done it um for demonstration purposes in the course of demonstration purposes in the course of demonstration purposes in the course of a a a day um so we um so we've actually had day um so we um so we've actually had day um so we um so we've actually had people do six cold water immersions people do six cold water immersions people do six cold water immersions they're only 3 minute immersions so they they're only 3 minute immersions so they they're only 3 minute immersions so they start at 9:00 in the morning and then do start at 9:00 in the morning and then do start at 9:00 in the morning and then do one every hour um and and straight after one every hour um and and straight after one every hour um and and straight after the immersion they have a shower because the immersion they have a shower because the immersion they have a shower because you've only cooled in in 3 minutes as I you've only cooled in in 3 minutes as I you've only cooled in in 3 minutes as I said earlier you know you've not really said earlier you know you've not really said earlier you know you've not really got any core cooling going on it's just got any core cooling going on it's just got any core cooling going on it's just the superficial skin uh and tissues that the superficial skin uh and tissues that the superficial skin uh and tissues that cool so you can very quickly warm them cool so you can very quickly warm them cool so you can very quickly warm them up with a shower and then rest for an up with a shower and then rest for an up with a shower and then rest for an hour and do the same and we've seen that hour and do the same and we've seen that hour and do the same and we've seen that protocol work over the course of a day protocol work over the course of a day protocol work over the course of a day um going through exactly the same kind um going through exactly the same kind um going through exactly the same kind kind of process as you would see if you

24:00kind of process as you would see if you kind of process as you would see if you did it one a day um so I you know I did it one a day um so I you know I did it one a day um so I you know I don't I how long you can leave between don't I how long you can leave between don't I how long you can leave between successive immersions whether you could successive immersions whether you could successive immersions whether you could leave it and do one a week I I I suspect leave it and do one a week I I I suspect leave it and do one a week I I I suspect the time course of the adaptation would the time course of the adaptation would the time course of the adaptation would be slower then um but the study hasn't be slower then um but the study hasn't be slower then um but the study hasn't really been really been really been done obviously metabolic health and done obviously metabolic health and done obviously metabolic health and chronic inflammation are very relevant chronic inflammation are very relevant chronic inflammation are very relevant to cardiovascular health too and there's to cardiovascular health too and there's to cardiovascular health too and there's some interesting science showing that some interesting science showing that some interesting science showing that cold exposure can affect metabolic cold exposure can affect metabolic cold exposure can affect metabolic health and inflammation so what are some health and inflammation so what are some health and inflammation so what are some of the potential upsides of cold water of the potential upsides of cold water of the potential upsides of cold water immersion on cardiovascular metabolic immersion on cardiovascular metabolic immersion on cardiovascular metabolic Health yeah I mean the preamble to this Health yeah I mean the preamble to this Health yeah I mean the preamble to this I which I'll keep brief is that for I which I'll keep brief is that for I which I'll keep brief is that for years we've looked at the Hazardous years we've looked at the Hazardous years we've looked at the Hazardous responses to cold water immersion um responses to cold water immersion um responses to cold water immersion um because of the great um toll in terms of because of the great um toll in terms of because of the great um toll in terms of lives lost and lives changed that that's lives lost and lives changed that that's lives lost and lives changed that that's resulted in um however in the background

25:00resulted in um however in the background resulted in um however in the background there's always been this um philosophy there's always been this um philosophy there's always been this um philosophy of going into the water for health and of going into the water for health and of going into the water for health and taking to the waters I mean I mean taking to the waters I mean I mean taking to the waters I mean I mean hypocrates did it Thomas Jefferson hypocrates did it Thomas Jefferson hypocrates did it Thomas Jefferson Darwin Florence Nightingale I mean you Darwin Florence Nightingale I mean you Darwin Florence Nightingale I mean you know the victorians did did I mean lots know the victorians did did I mean lots know the victorians did did I mean lots of Seaside towns in the UK Brighton of Seaside towns in the UK Brighton of Seaside towns in the UK Brighton penants places like that exist because penants places like that exist because penants places like that exist because of people wanting to go to the take to of people wanting to go to the take to of people wanting to go to the take to the waters and so there's always been the waters and so there's always been the waters and so there's always been this background of a health benefit of this background of a health benefit of this background of a health benefit of going into um going into um going into um seawater um which of course is going to seawater um which of course is going to seawater um which of course is going to be cold around the UK anyway um this be cold around the UK anyway um this be cold around the UK anyway um this took off during the pandemic where lots took off during the pandemic where lots took off during the pandemic where lots of people started doing Open Water of people started doing Open Water of people started doing Open Water swimming and cold dipping and cold swimming and cold dipping and cold swimming and cold dipping and cold swimming and it's now become something swimming and it's now become something swimming and it's now become something of a Vogue um you know it's hard to find of a Vogue um you know it's hard to find of a Vogue um you know it's hard to find somebody who's not doing Cold Water somebody who's not doing Cold Water somebody who's not doing Cold Water swimming at the moment um and the claims swimming at the moment um and the claims swimming at the moment um and the claims that are made for that are um normally that are made for that are um normally that are made for that are um normally threefold one it's alerting it wakes me

26:00threefold one it's alerting it wakes me threefold one it's alerting it wakes me up it sets me up for the day two I up it sets me up for the day two I up it sets me up for the day two I haven't had an upper respiratory tract haven't had an upper respiratory tract haven't had an upper respiratory tract infection for since I took up swimming infection for since I took up swimming infection for since I took up swimming Open Water swimming and three um some of Open Water swimming and three um some of Open Water swimming and three um some of the conditions that people have um both the conditions that people have um both the conditions that people have um both psychological and physical seem to psychological and physical seem to psychological and physical seem to improve or there are claims that they improve or there are claims that they improve or there are claims that they improve and that may well be an improve and that may well be an improve and that may well be an anti-inflammatory anti-inflammatory anti-inflammatory component um there is um a metabolic component um there is um a metabolic component um there is um a metabolic stimulus that comes from going into cold stimulus that comes from going into cold stimulus that comes from going into cold water because of course those cold water because of course those cold water because of course those cold receptors that are driving the receptors that are driving the receptors that are driving the cardiorespiratory system are also cardiorespiratory system are also cardiorespiratory system are also starting to activate the metabolic starting to activate the metabolic starting to activate the metabolic system to induce pre- shivering tone and system to induce pre- shivering tone and system to induce pre- shivering tone and shivering tone to defend deep body shivering tone to defend deep body shivering tone to defend deep body temperature and there are papers that um temperature and there are papers that um temperature and there are papers that um talk about alteration in adiposity and talk about alteration in adiposity and talk about alteration in adiposity and changes um in brown fat changes um in brown fat changes um in brown fat activation uh activation uh activation uh although I mean in in our world where although I mean in in our world where although I mean in in our world where we're talking about survival and heat we're talking about survival and heat we're talking about survival and heat large amounts of heat production large amounts of heat production large amounts of heat production necessary Brown fat is is a negligible

27:00necessary Brown fat is is a negligible necessary Brown fat is is a negligible contributor to that um so contributor to that um so contributor to that um so um now the alerting bit let's just um now the alerting bit let's just um now the alerting bit let's just quickly go through those the alerting quickly go through those the alerting quickly go through those the alerting bit is obvious because it's the cold bit is obvious because it's the cold bit is obvious because it's the cold shock response it's the release of the shock response it's the release of the shock response it's the release of the stress hormones it's that phal flight stress hormones it's that phal flight stress hormones it's that phal flight response so it's unsurprising that if response so it's unsurprising that if response so it's unsurprising that if you take a tropical animal who wants to you take a tropical animal who wants to you take a tropical animal who wants to be naked in 28 degree air and drop it be naked in 28 degree air and drop it be naked in 28 degree air and drop it into um naked into 12° water you're into um naked into 12° water you're into um naked into 12° water you're going to get a response that's alerting going to get a response that's alerting going to get a response that's alerting so we we understand that we understand so we we understand that we understand so we we understand that we understand the mechanisms and the pathways the mechanisms and the pathways the mechanisms and the pathways associated with that and we understand associated with that and we understand associated with that and we understand the hormones that are released in order the hormones that are released in order the hormones that are released in order to produce those to produce those to produce those responses um the anti- the anti um the responses um the anti- the anti um the responses um the anti- the anti um the uh immune function I think the jur is uh immune function I think the jur is uh immune function I think the jur is still out on that I mean one thing to still out on that I mean one thing to still out on that I mean one thing to say about this is this side of the say about this is this side of the say about this is this side of the double-edged sword of cold water double-edged sword of cold water double-edged sword of cold water immersion is much less um researched immersion is much less um researched immersion is much less um researched than the other side I mean we know we than the other side I mean we know we than the other side I mean we know we can talk for hours about the the can talk for hours about the the can talk for hours about the the Hazardous responses to cold and their

28:00Hazardous responses to cold and their Hazardous responses to cold and their Pathways and mechanisms and consequences Pathways and mechanisms and consequences Pathways and mechanisms and consequences most of the um evidence for the most of the um evidence for the most of the um evidence for the beneficial side is anecdotal although as beneficial side is anecdotal although as beneficial side is anecdotal although as I say to people anecdotal evidence is I say to people anecdotal evidence is I say to people anecdotal evidence is still evidence um although it's the still evidence um although it's the still evidence um although it's the weakest form of evidence so people um weakest form of evidence so people um weakest form of evidence so people um this upper respiratory tract infection this upper respiratory tract infection this upper respiratory tract infection we've seen in work we've done that we've seen in work we've done that we've seen in work we've done that there's a reduction in people who do there's a reduction in people who do there's a reduction in people who do Open Water swimming but there's an equal Open Water swimming but there's an equal Open Water swimming but there's an equal reduction in people who do inwater reduction in people who do inwater reduction in people who do inwater swimming in door swimming so um I think swimming in door swimming so um I think swimming in door swimming so um I think there's still some query about that and there's still some query about that and there's still some query about that and I think it's because what nobody has I think it's because what nobody has I think it's because what nobody has ever established or as yet is what's the ever established or as yet is what's the ever established or as yet is what's the dose of cold um and we know that a very dose of cold um and we know that a very dose of cold um and we know that a very brief cold water immersion is likely to brief cold water immersion is likely to brief cold water immersion is likely to activate the immune system but if you activate the immune system but if you activate the immune system but if you stay in too long and you start to cool stay in too long and you start to cool stay in too long and you start to cool it's actually likely to disable um the it's actually likely to disable um the it's actually likely to disable um the immune system so some of think I think immune system so some of think I think immune system so some of think I think some of the contradictory findings in some of the contradictory findings in some of the contradictory findings in the literature are partly due to what's the literature are partly due to what's the literature are partly due to what's being measured whether some of the

29:00being measured whether some of the being measured whether some of the measure whether some of the bloodborne measure whether some of the bloodborne measure whether some of the bloodborne markers of immune function are being markers of immune function are being markers of immune function are being measured or whether it's actually measured or whether it's actually measured or whether it's actually something like upper respiratory tract something like upper respiratory tract something like upper respiratory tract infections reported and also because infections reported and also because infections reported and also because people are doing different protocols my people are doing different protocols my people are doing different protocols my personal view is that um if there's a personal view is that um if there's a personal view is that um if there's a benefit to cold water immersion it's benefit to cold water immersion it's benefit to cold water immersion it's probably aced in the first couple of probably aced in the first couple of probably aced in the first couple of minutes it's associated with the with minutes it's associated with the with minutes it's associated with the with the cold shock response and the uh the cold shock response and the uh the cold shock response and the uh release of and and the neural stimul a release of and and the neural stimul a release of and and the neural stimul a and the release of the hormones and the release of the hormones and the release of the hormones associated with that just couple of associated with that just couple of associated with that just couple of minute immersions and then the longer minute immersions and then the longer minute immersions and then the longer you stay in cold water after that the you stay in cold water after that the you stay in cold water after that the more likely you are to have a problem of more likely you are to have a problem of more likely you are to have a problem of either in the acute or chronic either in the acute or chronic either in the acute or chronic phase the anti-inflammatory thing is um phase the anti-inflammatory thing is um phase the anti-inflammatory thing is um can be to do with things like face can be to do with things like face can be to do with things like face immersion which we've already AR immersion which we've already AR immersion which we've already AR discussed that in some situations it discussed that in some situations it discussed that in some situations it particularly hazardous but we know that particularly hazardous but we know that particularly hazardous but we know that um you know uh you get a powerful um you know uh you get a powerful um you know uh you get a powerful parasympathetic stimulation from a ning parasympathetic stimulation from a ning parasympathetic stimulation from a ning the face and we know that the Vegas

30:00the face and we know that the Vegas the face and we know that the Vegas nerve has been shown to have significant nerve has been shown to have significant nerve has been shown to have significant anti-inflammatory um effects in fact anti-inflammatory um effects in fact anti-inflammatory um effects in fact Vagas nerve stimulation is used to treat Vagas nerve stimulation is used to treat Vagas nerve stimulation is used to treat uh drug resistant epilepsy and uh drug resistant epilepsy and uh drug resistant epilepsy and depression in some parts of the world um depression in some parts of the world um depression in some parts of the world um we've actually done studies with um an we've actually done studies with um an we've actually done studies with um an individual had pretty profound individual had pretty profound individual had pretty profound depression and with repeated immersions depression and with repeated immersions depression and with repeated immersions in cold water she became depression and in cold water she became depression and in cold water she became depression and drug- free so we I think the summary of drug- free so we I think the summary of drug- free so we I think the summary of it is is that there are three main it is is that there are three main it is is that there are three main prongs um of claim we un we have a prongs um of claim we un we have a prongs um of claim we un we have a hypothesis for each of those but only hypothesis for each of those but only hypothesis for each of those but only really the cold shock and the alerting really the cold shock and the alerting really the cold shock and the alerting and Awakening side is fully understood and Awakening side is fully understood and Awakening side is fully understood um for the people that this benefits the um for the people that this benefits the um for the people that this benefits the thousands of people now I mean our local thousands of people now I mean our local thousands of people now I mean our local Club here in peror went from 25 to 1,000 Club here in peror went from 25 to 1,000 Club here in peror went from 25 to 1,000 members for the people who benefit from members for the people who benefit from members for the people who benefit from it that's that's it that's that's it that's that's sufficient sufficient sufficient um but as a scientist and what I want to um but as a scientist and what I want to um but as a scientist and what I want to know and what our group wants to know is know and what our group wants to know is know and what our group wants to know is what's what's going on and can we

31:00what's what's going on and can we what's what's going on and can we produce that um with a much less produce that um with a much less produce that um with a much less hazardous uh stimulus could you just put hazardous uh stimulus could you just put hazardous uh stimulus could you just put a hand and a foot could you do a cold a hand and a foot could you do a cold a hand and a foot could you do a cold pressure test um because there is no pressure test um because there is no pressure test um because there is no doubt that although there are beneficial doubt that although there are beneficial doubt that although there are beneficial effects um there are also potentially effects um there are also potentially effects um there are also potentially hazardous effects and we're seeing an hazardous effects and we're seeing an hazardous effects and we're seeing an increase in the number of deaths on increase in the number of deaths on increase in the number of deaths on immersion uh we're seeing an increase in immersion uh we're seeing an increase in immersion uh we're seeing an increase in the number of rescues required for the number of rescues required for the number of rescues required for people who go Open Water swimming people who go Open Water swimming people who go Open Water swimming and I my inbox is regularly um uh added and I my inbox is regularly um uh added and I my inbox is regularly um uh added to by people who had to by people who had to by people who had problems problems problems um you know and uh um you know and uh um you know and uh so yeah we want people to do what they so yeah we want people to do what they so yeah we want people to do what they want to do and if what they want to do want to do and if what they want to do want to do and if what they want to do is open Water Swimming great but it's is open Water Swimming great but it's is open Water Swimming great but it's our job to understand what's going on uh our job to understand what's going on uh our job to understand what's going on uh and also to make it as safe an activity and also to make it as safe an activity and also to make it as safe an activity as as as possible I worry that a lot of the possible I worry that a lot of the possible I worry that a lot of the narrative that's shared by scientist narrative that's shared by scientist narrative that's shared by scientist influences and physician influences has

32:00influences and physician influences has influences and physician influences has been a bit imbalanced and that's been been a bit imbalanced and that's been been a bit imbalanced and that's been exacerbated by some TV exacerbated by some TV exacerbated by some TV personalities and you spoke about personalities and you spoke about personalities and you spoke about rigorous experimentation I think a lot rigorous experimentation I think a lot rigorous experimentation I think a lot of the issues that we Face stem from the of the issues that we Face stem from the of the issues that we Face stem from the fact that we don't have well-controlled fact that we don't have well-controlled fact that we don't have well-controlled experiments and in these types of experiments and in these types of experiments and in these types of observational studies we can't really observational studies we can't really observational studies we can't really determine that it is the cold exposure determine that it is the cold exposure determine that it is the cold exposure that's leading to these benefits and that's leading to these benefits and that's leading to these benefits and when you think about Open Water Swimming when you think about Open Water Swimming when you think about Open Water Swimming there are many different beneficial there are many different beneficial there are many different beneficial stimulate at play there's the social stimulate at play there's the social stimulate at play there's the social component there's the physical activity component there's the physical activity component there's the physical activity there's the fact that they're taking there's the fact that they're taking there's the fact that they're taking place in natural environments there's place in natural environments there's place in natural environments there's the sun exposure all of these different the sun exposure all of these different the sun exposure all of these different things can independently have positive things can independently have positive things can independently have positive effects on somebody's Health but what effects on somebody's Health but what effects on somebody's Health but what you're saying is that there are you're saying is that there are you're saying is that there are potentially some upsides that are potentially some upsides that are potentially some upsides that are relevant both to cardiometabolic and relevant both to cardiometabolic and relevant both to cardiometabolic and brain health and those include things brain health and those include things brain health and those include things like the fact that this is going to like the fact that this is going to like the fact that this is going to increase glucose uptake into muscles if increase glucose uptake into muscles if increase glucose uptake into muscles if they are more active as a result of they are more active as a result of they are more active as a result of shivering thermogenesis for example shivering thermogenesis for example shivering thermogenesis for example there's a lot of talk nowadays about ocy

33:00there's a lot of talk nowadays about ocy there's a lot of talk nowadays about ocy Browning and brown adapost tissue Browning and brown adapost tissue Browning and brown adapost tissue thermogenesis and interestingly there thermogenesis and interestingly there thermogenesis and interestingly there seems to be some evidence suggesting seems to be some evidence suggesting seems to be some evidence suggesting that even sleeping in a cool room might that even sleeping in a cool room might that even sleeping in a cool room might increase Brown adapost tissue increase Brown adapost tissue increase Brown adapost tissue thermogenesis and yield and positive thermogenesis and yield and positive thermogenesis and yield and positive effects on insulin sensitivity for effects on insulin sensitivity for effects on insulin sensitivity for example and people with poor blood sugar example and people with poor blood sugar example and people with poor blood sugar control but then turning to the brain so control but then turning to the brain so control but then turning to the brain so many people are now advocating cold many people are now advocating cold many people are now advocating cold immersion at the start of a working day immersion at the start of a working day immersion at the start of a working day and they focus on some of the mechanisms and they focus on some of the mechanisms and they focus on some of the mechanisms that are at play you get this strong that are at play you get this strong that are at play you get this strong increase in noradrenaline in the brain increase in noradrenaline in the brain increase in noradrenaline in the brain and that's having some acute effects on and that's having some acute effects on and that's having some acute effects on alertness and possibly some other alertness and possibly some other alertness and possibly some other positive effects on simple cognitive positive effects on simple cognitive positive effects on simple cognitive functions like reaction time but I'm functions like reaction time but I'm functions like reaction time but I'm curious about what your thoughts are curious about what your thoughts are curious about what your thoughts are on the likely effects on more complex on the likely effects on more complex on the likely effects on more complex cognitive functions bear in mind that cognitive functions bear in mind that cognitive functions bear in mind that lots of people who are doing this are lots of people who are doing this are lots of people who are doing this are using it for knowledge work and they using it for knowledge work and they using it for knowledge work and they need faculties like working memory need faculties like working memory need faculties like working memory executive functions and my impression executive functions and my impression executive functions and my impression having looked at some of the research on

34:00having looked at some of the research on having looked at some of the research on cold exposure not through water but just cold exposure not through water but just cold exposure not through water but just through cold ambient conditions is that through cold ambient conditions is that through cold ambient conditions is that these tend to be hampered rather than these tend to be hampered rather than these tend to be hampered rather than improved by Cold exposure yeah I mean I improved by Cold exposure yeah I mean I improved by Cold exposure yeah I mean I think probably the easiest General think probably the easiest General think probably the easiest General comment to make on that is we're back to comment to make on that is we're back to comment to make on that is we're back to the issue of dose of cold um if you have the issue of dose of cold um if you have the issue of dose of cold um if you have a short period of cold exposure that you a short period of cold exposure that you a short period of cold exposure that you know I'm talking second know I'm talking second know I'm talking second uh not even minutes that's sufficient to uh not even minutes that's sufficient to uh not even minutes that's sufficient to release the stress hormones you're release the stress hormones you're release the stress hormones you're likely to improve you know things like likely to improve you know things like likely to improve you know things like attention vigilance you know the some of attention vigilance you know the some of attention vigilance you know the some of the simple more simpler um responses um the simple more simpler um responses um the simple more simpler um responses um if you've got if you've if you've spent if you've got if you've if you've spent if you've got if you've if you've spent a longer period in cold then I think a longer period in cold then I think a longer period in cold then I think they'll you'll start to move down the they'll you'll start to move down the they'll you'll start to move down the down the path of that being degraded and down the path of that being degraded and down the path of that being degraded and often it's um one of the problems with often it's um one of the problems with often it's um one of the problems with these um types of studies of course is these um types of studies of course is these um types of studies of course is the way you're measuring things like

35:00the way you're measuring things like the way you're measuring things like reaction time or complex reaction time reaction time or complex reaction time reaction time or complex reaction time um that's that in itself is impacted by um that's that in itself is impacted by um that's that in itself is impacted by the fact you've got peripheral cooling the fact you've got peripheral cooling the fact you've got peripheral cooling so you know the whole thing gets very so you know the whole thing gets very so you know the whole thing gets very complicated I when people get in touch complicated I when people get in touch complicated I when people get in touch with me if they say I want to take up with me if they say I want to take up with me if they say I want to take up cold water immersion for weight um loss cold water immersion for weight um loss cold water immersion for weight um loss let's say or metabolic Health I'll often let's say or metabolic Health I'll often let's say or metabolic Health I'll often say well you're much better off going say well you're much better off going say well you're much better off going for a walk um because you're now you for a walk um because you're now you for a walk um because you're now you know you're you're you're now know you're you're you're now know you're you're you're now weightbearing and you're going to get a weightbearing and you're going to get a weightbearing and you're going to get a lot more bang for your buck with a half lot more bang for your buck with a half lot more bang for your buck with a half an hour half an hour walk than you are an hour half an hour walk than you are an hour half an hour walk than you are with a half an hour float um if you want with a half an hour float um if you want with a half an hour float um if you want you know if you want you know if you want you know if you want to uh so it depends what you're trying to uh so it depends what you're trying to uh so it depends what you're trying to do I mean if it's and I agree to do I mean if it's and I agree to do I mean if it's and I agree entirely entirely entirely the what we don't know is when somebody the what we don't know is when somebody the what we don't know is when somebody goes and does we haven't really goes and does we haven't really goes and does we haven't really identified the active ingredient in Open identified the active ingredient in Open identified the active ingredient in Open Water Swimming um whether it's meeting Water Swimming um whether it's meeting Water Swimming um whether it's meeting friends you know the green the blue friends you know the green the blue friends you know the green the blue therapy the the being weightless the therapy the the being weightless the therapy the the being weightless the doing some exercise or the getting cold doing some exercise or the getting cold doing some exercise or the getting cold um or the having the cake and a hot

36:00um or the having the cake and a hot um or the having the cake and a hot chocolate afterwards and so all of these chocolate afterwards and so all of these chocolate afterwards and so all of these things uh until the studies are done things uh until the studies are done things uh until the studies are done which I'm not sure they're going to get which I'm not sure they're going to get which I'm not sure they're going to get done because it's really hard to get done because it's really hard to get done because it's really hard to get funding for that type of study much funding for that type of study much funding for that type of study much easier to get funding for sudden cardiac easier to get funding for sudden cardiac easier to get funding for sudden cardiac death on immersion and drowning and hyp death on immersion and drowning and hyp death on immersion and drowning and hyp hypothermia um but until those trials hypothermia um but until those trials hypothermia um but until those trials are done where you've isolated cold and are done where you've isolated cold and are done where you've isolated cold and we're never really going to know um we're never really going to know um we're never really going to know um and in the meantime as I say I mean and in the meantime as I say I mean and in the meantime as I say I mean anecdotal evidence is still evidence anecdotal evidence is still evidence anecdotal evidence is still evidence that's fine and a placebo effect is that's fine and a placebo effect is that's fine and a placebo effect is still an effect but it doesn't really still an effect but it doesn't really still an effect but it doesn't really Advance us anywhere in terms of what's Advance us anywhere in terms of what's Advance us anywhere in terms of what's going on we know about vagal stimulation going on we know about vagal stimulation going on we know about vagal stimulation we know about anti-inflammatory cyto we know about anti-inflammatory cyto we know about anti-inflammatory cyto kind initiation we know about serotonin kind initiation we know about serotonin kind initiation we know about serotonin release we've got lots of release we've got lots of release we've got lots of hypotheses um but uh which would affect hypotheses um but uh which would affect hypotheses um but uh which would affect you know physical and mental well-being you know physical and mental well-being you know physical and mental well-being but as yet that's not been teased out at

37:00but as yet that's not been teased out at but as yet that's not been teased out at all nearly all of the studies are all nearly all of the studies are all nearly all of the studies are descriptive they go you know people who descriptive they go you know people who descriptive they go you know people who are doing Open Water Swimming are asked are doing Open Water Swimming are asked are doing Open Water Swimming are asked whether they think it's good for them um whether they think it's good for them um whether they think it's good for them um I would suggest that they would be I would suggest that they would be I would suggest that they would be really strange individuals if they said really strange individuals if they said really strange individuals if they said no and your comment about manual no and your comment about manual no and your comment about manual dexterity was interesting because some dexterity was interesting because some dexterity was interesting because some of these cognitive tests rely on people of these cognitive tests rely on people of these cognitive tests rely on people pressing something in response to some pressing something in response to some pressing something in response to some sort of stimulus and if they've got sort of stimulus and if they've got sort of stimulus and if they've got peripheral calling of their muscles in peripheral calling of their muscles in peripheral calling of their muscles in their nerves then they're not going to their nerves then they're not going to their nerves then they're not going to be able to move their hands as well so be able to move their hands as well so be able to move their hands as well so it's one of those experimental variables it's one of those experimental variables it's one of those experimental variables that you need to actually consider as a that you need to actually consider as a that you need to actually consider as a scientist and it's probably only people scientist and it's probably only people scientist and it's probably only people like you that would be aware of those like you that would be aware of those like you that would be aware of those Mike but that brings up the subject of Mike but that brings up the subject of Mike but that brings up the subject of non-freezing cold injury in a very non-freezing cold injury in a very non-freezing cold injury in a very roundabout way and I mentioned this just roundabout way and I mentioned this just roundabout way and I mentioned this just because it's probably not something because it's probably not something because it's probably not something that's on The Radars of many people can that's on The Radars of many people can that's on The Radars of many people can you just explain what non-freezing cold you just explain what non-freezing cold you just explain what non-freezing cold injury is because hypothermia gets so injury is because hypothermia gets so injury is because hypothermia gets so much air time but my impression is this much air time but my impression is this much air time but my impression is this might be more burdensome might be more burdensome might be more burdensome yeah you're right Greg that this when yeah you're right Greg that this when yeah you're right Greg that this when people talk about the positive negative

38:00people talk about the positive negative people talk about the positive negative effects of doing Cold Water Swimming effects of doing Cold Water Swimming effects of doing Cold Water Swimming dipping ice you know the ice mile dipping ice you know the ice mile dipping ice you know the ice mile they'll they'll talk about you know they'll they'll talk about you know they'll they'll talk about you know they'll worry about the heart they'll they'll worry about the heart they'll they'll worry about the heart they'll worry about aneurisms and hypertension worry about aneurisms and hypertension worry about aneurisms and hypertension and they'll worry about potentially you and they'll worry about potentially you and they'll worry about potentially you know drowning what nobody what you know drowning what nobody what you know drowning what nobody what you really rarely see in the literature is really rarely see in the literature is really rarely see in the literature is well what about damage to my peripheral well what about damage to my peripheral well what about damage to my peripheral vasculature and what most most of your vasculature and what most most of your vasculature and what most most of your listeners will have heard of is listeners will have heard of is listeners will have heard of is frostbite because that's you know well frostbite because that's you know well frostbite because that's you know well well known and understood and the Gory well known and understood and the Gory well known and understood and the Gory pictures of Mountaineers losing you know pictures of Mountaineers losing you know pictures of Mountaineers losing you know bits of their extremities because of bits of their extremities because of bits of their extremities because of frostbite but there is another condition frostbite but there is another condition frostbite but there is another condition um that is equally um debilitating um that is equally um debilitating um that is equally um debilitating although much less wellknown which is although much less wellknown which is although much less wellknown which is non-freezing cold injury and as the name non-freezing cold injury and as the name non-freezing cold injury and as the name suggests it's it's an injury to um suggests it's it's an injury to um suggests it's it's an injury to um particularly the extremities again it's particularly the extremities again it's particularly the extremities again it's the same areas as you would suffer from the same areas as you would suffer from the same areas as you would suffer from frostbite but there's no freezing of the

39:00frostbite but there's no freezing of the frostbite but there's no freezing of the tissue goes on it's just a damage to the tissue goes on it's just a damage to the tissue goes on it's just a damage to the microvascular and and microvascular and and microvascular and and neurovascular um tissues as a result of neurovascular um tissues as a result of neurovascular um tissues as a result of pro prolonged exposure to cool pro prolonged exposure to cool pro prolonged exposure to cool conditions so historically you may have conditions so historically you may have conditions so historically you may have heard of terms such as Patty foot trench heard of terms such as Patty foot trench heard of terms such as Patty foot trench foot these kind of conditions and you foot these kind of conditions and you foot these kind of conditions and you know I suspect this this is on a know I suspect this this is on a know I suspect this this is on a Continuum I suspect anybody who's you Continuum I suspect anybody who's you Continuum I suspect anybody who's you know grown up Outdoors WR written a know grown up Outdoors WR written a know grown up Outdoors WR written a motorbike played Field Sports done any motorbike played Field Sports done any motorbike played Field Sports done any mountaineering will have a degree of uh mountaineering will have a degree of uh mountaineering will have a degree of uh peripheral neurovascular damage micr peripheral neurovascular damage micr peripheral neurovascular damage micr neurovascular damage um but it doesn't neurovascular damage um but it doesn't neurovascular damage um but it doesn't really impact them they might just find really impact them they might just find really impact them they might just find that their feet are cold um get cold that their feet are cold um get cold that their feet are cold um get cold really easily stay cold long a long really easily stay cold long a long really easily stay cold long a long while and hard to while and hard to while and hard to rearm um but that can progress to um rearm um but that can progress to um rearm um but that can progress to um permanent pain sweating in the damaged permanent pain sweating in the damaged permanent pain sweating in the damaged area and cold

40:00area and cold area and cold sensitivity and you know at worst it's sensitivity and you know at worst it's sensitivity and you know at worst it's lifechanging uh may involve amputation lifechanging uh may involve amputation lifechanging uh may involve amputation in in the fullness of time and again in in the fullness of time and again in in the fullness of time and again it's it's a condition that you rarely it's it's a condition that you rarely it's it's a condition that you rarely hear spoken about full stop and you hear spoken about full stop and you hear spoken about full stop and you certainly rarely hear it spoken about in certainly rarely hear it spoken about in certainly rarely hear it spoken about in individuals who are trying to spend individuals who are trying to spend individuals who are trying to spend longer and longer in colder and colder longer and longer in colder and colder longer and longer in colder and colder water uh it's I mean the problem with it water uh it's I mean the problem with it water uh it's I mean the problem with it is we don't really know very much about is we don't really know very much about is we don't really know very much about non-freezing cold injury it's never non-freezing cold injury it's never non-freezing cold injury it's never really got to the top of the pile to um really got to the top of the pile to um really got to the top of the pile to um you know get the funding to look into you know get the funding to look into you know get the funding to look into the the the pathogenesis and the the the the pathogenesis and the the the the pathogenesis and the pathology um there and also I mean we're pathology um there and also I mean we're pathology um there and also I mean we're not even sure whether it's primarily a not even sure whether it's primarily a not even sure whether it's primarily a vascular injury or a a neural injury or vascular injury or a a neural injury or vascular injury or a a neural injury or whether it's vascular causing neural or whether it's vascular causing neural or whether it's vascular causing neural or neural causing vasculature but we do neural causing vasculature but we do neural causing vasculature but we do know it's a problem and we do know it's know it's a problem and we do know it's know it's a problem and we do know it's a lifelong problem when you know when I a lifelong problem when you know when I a lifelong problem when you know when I was at the Institute Naval medicine was at the Institute Naval medicine was at the Institute Naval medicine there were people still being tested for there were people still being tested for there were people still being tested for non-freezing cold injury in the 80s and

41:00non-freezing cold injury in the 80s and non-freezing cold injury in the 80s and '90s who had picked up their injury in '90s who had picked up their injury in '90s who had picked up their injury in the the the 50s so uh it's certainly something that 50s so uh it's certainly something that 50s so uh it's certainly something that needs needs needs to people need to be made more aware to people need to be made more aware to people need to be made more aware about and the good news is that we're about and the good news is that we're about and the good news is that we're actually about to launch a website um my actually about to launch a website um my actually about to launch a website um my colleague Dr CLA Frank um Dr CLA Eglin colleague Dr CLA Frank um Dr CLA Eglin colleague Dr CLA Frank um Dr CLA Eglin sorry she was she was Franks um is about sorry she was she was Franks um is about sorry she was she was Franks um is about to to um launch a website on um the to to um launch a website on um the to to um launch a website on um the Portsmouth University website which will Portsmouth University website which will Portsmouth University website which will give you lots of you know information give you lots of you know information give you lots of you know information about non-freezing cold injury and about non-freezing cold injury and about non-freezing cold injury and answer the frequently asked questions we answer the frequently asked questions we answer the frequently asked questions we can spend a lot more time speaking about can spend a lot more time speaking about can spend a lot more time speaking about exercise specifically but I'll just exercise specifically but I'll just exercise specifically but I'll just point out a couple of things that I've point out a couple of things that I've point out a couple of things that I've learned or had drilled home while learned or had drilled home while learned or had drilled home while familiarizing myself with your work Mike familiarizing myself with your work Mike familiarizing myself with your work Mike one of them is that some people will use one of them is that some people will use one of them is that some people will use precooling before exercising the heat to precooling before exercising the heat to precooling before exercising the heat to improve improved performance and that's improve improved performance and that's improve improved performance and that's often done by way of something like an often done by way of something like an often done by way of something like an ice Fest but that's not necessarily

42:00ice Fest but that's not necessarily ice Fest but that's not necessarily optimal in part because cold exposure optimal in part because cold exposure optimal in part because cold exposure can acutely lead to diuresis and so can acutely lead to diuresis and so can acutely lead to diuresis and so given that fluid balance is so important given that fluid balance is so important given that fluid balance is so important to exercis in the heat the net effect to exercis in the heat the net effect to exercis in the heat the net effect might not necessarily be positive and if might not necessarily be positive and if might not necessarily be positive and if precooling is used then arguably people precooling is used then arguably people precooling is used then arguably people should pay attention to their hydration should pay attention to their hydration should pay attention to their hydration and then secondarily lots of people use and then secondarily lots of people use and then secondarily lots of people use cold exposure post exercise his this has cold exposure post exercise his this has cold exposure post exercise his this has often been done to reduce inflammation often been done to reduce inflammation often been done to reduce inflammation and Associated delayed onset muscle and Associated delayed onset muscle and Associated delayed onset muscle soreness Doms but there's some evidence soreness Doms but there's some evidence soreness Doms but there's some evidence suggesting that that could actually suggesting that that could actually suggesting that that could actually hinder some training adaptations in the hinder some training adaptations in the hinder some training adaptations in the same way that other forms of reducing same way that other forms of reducing same way that other forms of reducing inflammation such as taking inflammation such as taking inflammation such as taking anti-inflammatory neutri cools including anti-inflammatory neutri cools including anti-inflammatory neutri cools including high dose antioxidant vitamins can high dose antioxidant vitamins can high dose antioxidant vitamins can hamper some of those adaptations but i' hamper some of those adaptations but i' hamper some of those adaptations but i' love to move on to some ways by which we love to move on to some ways by which we love to move on to some ways by which we can progress cold exposure and think can progress cold exposure and think can progress cold exposure and think about a spectrum of different types of

43:00about a spectrum of different types of about a spectrum of different types of interventions according to how intensive interventions according to how intensive interventions according to how intensive they are and I was thinking about this they are and I was thinking about this they are and I was thinking about this before recording today and it struck me before recording today and it struck me before recording today and it struck me that maybe the lowest end of the that maybe the lowest end of the that maybe the lowest end of the spectrum that one could consider would spectrum that one could consider would spectrum that one could consider would be to actually use something like be to actually use something like be to actually use something like Menthol application or ingestion because Menthol application or ingestion because Menthol application or ingestion because that seems to stimulate some of the same that seems to stimulate some of the same that seems to stimulate some of the same receptors that are involved in receptors that are involved in receptors that are involved in initiating responses to codes initiating responses to codes initiating responses to codes specifically the trip M8 receptors so I specifically the trip M8 receptors so I specifically the trip M8 receptors so I was curious about whether you thought at was curious about whether you thought at was curious about whether you thought at all about whether that might be a all about whether that might be a all about whether that might be a gateway to cold adaptation or whether gateway to cold adaptation or whether gateway to cold adaptation or whether that would just be an insufficient that would just be an insufficient that would just be an insufficient stimulus to initiate the response yeah stimulus to initiate the response yeah stimulus to initiate the response yeah it's a good question it's one we asked a it's a good question it's one we asked a it's a good question it's one we asked a few years ago with uh a PhD done in our few years ago with uh a PhD done in our few years ago with uh a PhD done in our lab by Jason Gillis and we did some work lab by Jason Gillis and we did some work lab by Jason Gillis and we did some work also with um uh Phil Newton and Martin also with um uh Phil Newton and Martin also with um uh Phil Newton and Martin bwood and uh we were looking at in those bwood and uh we were looking at in those bwood and uh we were looking at in those Days the original question came from uh Days the original question came from uh Days the original question came from uh an a product that was a vest that was

44:00an a product that was a vest that was an a product that was a vest that was soaked in Menthol and ethanol and it was soaked in Menthol and ethanol and it was soaked in Menthol and ethanol and it was a cooling vest that was supposed to the a cooling vest that was supposed to the a cooling vest that was supposed to the ethanol was supposed to increase ethanol was supposed to increase ethanol was supposed to increase evaporative cooling because ethanol evaporative cooling because ethanol evaporative cooling because ethanol evaporates more easily and the uh evaporates more easily and the uh evaporates more easily and the uh Menthol was supposed to stimulate cold Menthol was supposed to stimulate cold Menthol was supposed to stimulate cold receptors which is as you've mentioned receptors which is as you've mentioned receptors which is as you've mentioned and which is why it's including lots of and which is why it's including lots of and which is why it's including lots of products that claim to make you feel products that claim to make you feel products that claim to make you feel fresh because it's actually cold fresh because it's actually cold fresh because it's actually cold receptors that are being stimulated and receptors that are being stimulated and receptors that are being stimulated and we did look at it we did I mean people we did look at it we did I mean people we did look at it we did I mean people can look up the papers themselves um but can look up the papers themselves um but can look up the papers themselves um but we looked at um the impact of the we looked at um the impact of the we looked at um the impact of the application of Menthol and interestingly application of Menthol and interestingly application of Menthol and interestingly although it made you feel cooler the although it made you feel cooler the although it made you feel cooler the other thing it did it activated the heat other thing it did it activated the heat other thing it did it activated the heat conservation Pathways so it might make conservation Pathways so it might make conservation Pathways so it might make you feel cooler but actually you start you feel cooler but actually you start you feel cooler but actually you start to defend that temperature so overall to defend that temperature so overall to defend that temperature so overall it's not making any difference to your it's not making any difference to your it's not making any difference to your deep body temperature because you've deep body temperature because you've deep body temperature because you've just Vasa constricted a bit the other just Vasa constricted a bit the other just Vasa constricted a bit the other interesting thing is repeated interesting thing is repeated interesting thing is repeated application and um induces an application and um induces an application and um induces an habituation so actually you habituate to habituation so actually you habituate to habituation so actually you habituate to repeated Menthol application in the same

45:00repeated Menthol application in the same repeated Menthol application in the same way as you would habituate to repeated way as you would habituate to repeated way as you would habituate to repeated cold but the most important point is the cold but the most important point is the cold but the most important point is the last one you made which is um that it last one you made which is um that it last one you made which is um that it really is a pretty minimal stimulation really is a pretty minimal stimulation really is a pretty minimal stimulation in comparison with cold water so nobody in comparison with cold water so nobody in comparison with cold water so nobody to my knowledge has done the study of to my knowledge has done the study of to my knowledge has done the study of repeat Menthol application and then repeat Menthol application and then repeat Menthol application and then looked at um whether that changes your looked at um whether that changes your looked at um whether that changes your response to immersion but my guess is it response to immersion but my guess is it response to immersion but my guess is it wouldn't next up the Spectrum might be wouldn't next up the Spectrum might be wouldn't next up the Spectrum might be something like a cold pressure test something like a cold pressure test something like a cold pressure test something like exposing the hands or the something like exposing the hands or the something like exposing the hands or the feet to cold water they have certain feet to cold water they have certain feet to cold water they have certain characteristics that mean that we're characteristics that mean that we're characteristics that mean that we're able to gain or lose heat through them able to gain or lose heat through them able to gain or lose heat through them very efficiently they've got a large very efficiently they've got a large very efficiently they've got a large surface area to mass ratio they're dense surface area to mass ratio they're dense surface area to mass ratio they're dense with arterio Venus and asmosis so what with arterio Venus and asmosis so what with arterio Venus and asmosis so what about just plunging your hands or your about just plunging your hands or your about just plunging your hands or your feet into cold water for a few minutes feet into cold water for a few minutes feet into cold water for a few minutes as a better Gateway than using men as a better Gateway than using men as a better Gateway than using men yeah well it's certainly a more yeah well it's certainly a more yeah well it's certainly a more significant stress anyone who's done a

46:00significant stress anyone who's done a significant stress anyone who's done a cold pressor test will know it's you cold pressor test will know it's you cold pressor test will know it's you know it's it's it's fairly tough um in know it's it's it's fairly tough um in know it's it's it's fairly tough um in that you're putting uh hand or a hand that you're putting uh hand or a hand that you're putting uh hand or a hand and a foot into water that's you and a foot into water that's you and a foot into water that's you freezing cold and you will see uh an freezing cold and you will see uh an freezing cold and you will see uh an increase in heart rate you don't see the increase in heart rate you don't see the increase in heart rate you don't see the Gasping uncontrollable Gasping uncontrollable Gasping uncontrollable hyperventilation and you know hyperventilation and you know hyperventilation and you know increase and increase blood pressure to increase and increase blood pressure to increase and increase blood pressure to the levels you'd see with whole body the levels you'd see with whole body the levels you'd see with whole body immersion but it's certainly a step in immersion but it's certainly a step in immersion but it's certainly a step in the right direction in terms of you're the right direction in terms of you're the right direction in terms of you're wanting to up the cold stimulus what we wanting to up the cold stimulus what we wanting to up the cold stimulus what we don't know and it's part of the reason don't know and it's part of the reason don't know and it's part of the reason why we want to go beyond the anecdotal why we want to go beyond the anecdotal why we want to go beyond the anecdotal evidence of the Open Water Swimming is evidence of the Open Water Swimming is evidence of the Open Water Swimming is whether it's sufficient to induce any of whether it's sufficient to induce any of whether it's sufficient to induce any of the well-being effects whether it's the well-being effects whether it's the well-being effects whether it's physical and mental that we see with physical and mental that we see with physical and mental that we see with whole body immersion so you know The whole body immersion so you know The whole body immersion so you know The $64,000 Question is what's the minimum $64,000 Question is what's the minimum $64,000 Question is what's the minimum surface area you need to um stimulate surface area you need to um stimulate surface area you need to um stimulate with cold in order to get the beneficial with cold in order to get the beneficial with cold in order to get the beneficial effects now um there's some indication

47:00effects now um there's some indication effects now um there's some indication by going from Whole Body immersion to by going from Whole Body immersion to by going from Whole Body immersion to showering for example that showering um showering for example that showering um showering for example that showering um can produce some of these beneficial can produce some of these beneficial can produce some of these beneficial effects but we know that showering is effects but we know that showering is effects but we know that showering is not the same level of stimulation that not the same level of stimulation that not the same level of stimulation that may be the next level of stimulation may be the next level of stimulation may be the next level of stimulation that you're coming on to but it's but that you're coming on to but it's but that you're coming on to but it's but it's you know we don't know the answer it's you know we don't know the answer it's you know we don't know the answer we don't know the answer to that we don't know the answer to that we don't know the answer to that question but there's no you're question but there's no you're question but there's no you're definitely activating the pathways definitely activating the pathways definitely activating the pathways although not to the degree um that you although not to the degree um that you although not to the degree um that you would see with a whole body immersion would see with a whole body immersion would see with a whole body immersion you you rarely see a big respiratory you you rarely see a big respiratory you you rarely see a big respiratory response to a cold pressure test mostly response to a cold pressure test mostly response to a cold pressure test mostly the the response is the the response is the the response is cardiovascular it was indeed showering cardiovascular it was indeed showering cardiovascular it was indeed showering very press interview Mike and I was very press interview Mike and I was very press interview Mike and I was going to also ask about how somebody going to also ask about how somebody going to also ask about how somebody might progress the showers in terms of might progress the showers in terms of might progress the showers in terms of the surface area that's exposed to the the surface area that's exposed to the the surface area that's exposed to the cold water Andor the temperature Andor cold water Andor the temperature Andor cold water Andor the temperature Andor the duration I know that you've done the duration I know that you've done the duration I know that you've done some work looking at showers as part of

48:00some work looking at showers as part of some work looking at showers as part of a cold adaptation protocol y so um a cold adaptation protocol y so um a cold adaptation protocol y so um showering is about 40% of the body showering is about 40% of the body showering is about 40% of the body surface area compared to whole body surface area compared to whole body surface area compared to whole body headout immersion which is you know n on headout immersion which is you know n on headout immersion which is you know n on about 90% so um the showering is not so about 90% so um the showering is not so about 90% so um the showering is not so effective but it does evoke a response effective but it does evoke a response effective but it does evoke a response and you can habituate to that response and you can habituate to that response and you can habituate to that response by repeated showers you can um by repeated showers you can um by repeated showers you can um increase the surface area there's ways increase the surface area there's ways increase the surface area there's ways of going about it to make it more of going about it to make it more of going about it to make it more comfortable you can start with a warm comfortable you can start with a warm comfortable you can start with a warm shower and go cold that doesn't give you shower and go cold that doesn't give you shower and go cold that doesn't give you the same stimulus as if you go straight the same stimulus as if you go straight the same stimulus as if you go straight into cold because the rate of change of into cold because the rate of change of into cold because the rate of change of skin temperature which is the driver for skin temperature which is the driver for skin temperature which is the driver for the cold chock response is less um you the cold chock response is less um you the cold chock response is less um you can start with your back to the shower can start with your back to the shower can start with your back to the shower and once that you've done 30 seconds of and once that you've done 30 seconds of and once that you've done 30 seconds of that you can turn to face the shower um that you can turn to face the shower um that you can turn to face the shower um just with the warning that as soon as just with the warning that as soon as just with the warning that as soon as you start putting your face under the you start putting your face under the you start putting your face under the cold water and associated with holding cold water and associated with holding cold water and associated with holding your breath you're increasing your your breath you're increasing your your breath you're increasing your likelihood of cardiac arhythmia so if likelihood of cardiac arhythmia so if likelihood of cardiac arhythmia so if you're going to do back and front do

49:00you're going to do back and front do you're going to do back and front do back and chest not back and back and chest not back and back and chest not back and face um and um you know we've face um and um you know we've face um and um you know we've demonstrated that you can see an demonstrated that you can see an demonstrated that you can see an habituation it's not as great in habituation it's not as great in habituation it's not as great in habituation as you see with repeated habituation as you see with repeated habituation as you see with repeated cold water immersions but you do see cold water immersions but you do see cold water immersions but you do see some habituation on immersion having had some habituation on immersion having had some habituation on immersion having had cold showers but it's you know then as cold showers but it's you know then as cold showers but it's you know then as we as we're discussing it's it's a level we as we're discussing it's it's a level we as we're discussing it's it's a level down from Whole Body down from Whole Body down from Whole Body immersion I'm glad that you mentioned immersion I'm glad that you mentioned immersion I'm glad that you mentioned preheating because I see a lot of people preheating because I see a lot of people preheating because I see a lot of people advocating the contrast method where advocating the contrast method where advocating the contrast method where they might for example use the SAA they might for example use the SAA they might for example use the SAA before cold showers and Alternate back before cold showers and Alternate back before cold showers and Alternate back and forth between them but if we think and forth between them but if we think and forth between them but if we think about the next level that might be about the next level that might be about the next level that might be bathing in a body of cold water which I bathing in a body of cold water which I bathing in a body of cold water which I suppose could start with staying suppose could start with staying suppose could start with staying relatively still and then moving the relatively still and then moving the relatively still and then moving the limbs so that there isn't that boundary limbs so that there isn't that boundary limbs so that there isn't that boundary layer that's being heated and there's a layer that's being heated and there's a layer that's being heated and there's a stronger thermal stret dress might that stronger thermal stret dress might that stronger thermal stret dress might that make sense and could you go from there make sense and could you go from there make sense and could you go from there to immersing the face in the water as

50:00to immersing the face in the water as to immersing the face in the water as well to add on the intensity well to add on the intensity well to add on the intensity stimulus yeah I think so the static stimulus yeah I think so the static stimulus yeah I think so the static immersions are fine I mean I happen to immersions are fine I mean I happen to immersions are fine I mean I happen to believe that the benefits of that people believe that the benefits of that people believe that the benefits of that people are claiming for cold water immersion are claiming for cold water immersion are claiming for cold water immersion probably come from just sudden cooling probably come from just sudden cooling probably come from just sudden cooling of the skin on initial immersion I think of the skin on initial immersion I think of the skin on initial immersion I think the exercise if anything um confuses the the exercise if anything um confuses the the exercise if anything um confuses the picture because now you don't know picture because now you don't know picture because now you don't know whether it's the exercise or the cold whether it's the exercise or the cold whether it's the exercise or the cold but I suspect the exercise is not but I suspect the exercise is not but I suspect the exercise is not necessary um the problem with putting necessary um the problem with putting necessary um the problem with putting your face in which I think is important your face in which I think is important your face in which I think is important at one level in terms of we've talked at one level in terms of we've talked at one level in terms of we've talked about the vagal response and we've about the vagal response and we've about the vagal response and we've talked about um that having significant talked about um that having significant talked about um that having significant anti-inflammatory responses um I think anti-inflammatory responses um I think anti-inflammatory responses um I think that's uh okay provided again you're that's uh okay provided again you're that's uh okay provided again you're conscious of the fact that that face conscious of the fact that that face conscious of the fact that that face immersion doesn't want to be um as part immersion doesn't want to be um as part immersion doesn't want to be um as part of a protracted breath hole because of of a protracted breath hole because of of a protracted breath hole because of the increased danger of cardiac arithm the increased danger of cardiac arithm the increased danger of cardiac arithm is on breaking that breath hole so yeah is on breaking that breath hole so yeah is on breaking that breath hole so yeah I think that you've got to the point I think that you've got to the point I think that you've got to the point where you probably don't need the

51:00where you probably don't need the where you probably don't need the exercise the exercise will be good for exercise the exercise will be good for exercise the exercise will be good for you but if you're trying to tease out you but if you're trying to tease out you but if you're trying to tease out whether it's the cold or the exercise uh whether it's the cold or the exercise uh whether it's the cold or the exercise uh and if you're going into freezing cold and if you're going into freezing cold and if you're going into freezing cold water to exercise as I said before water to exercise as I said before water to exercise as I said before you're much better off just exercising you're much better off just exercising you're much better off just exercising in air because you'll consume more in air because you'll consume more in air because you'll consume more calories and you'll you know challenge calories and you'll you know challenge calories and you'll you know challenge yourself much more by walking along the yourself much more by walking along the yourself much more by walking along the cliff than you will by swimming in the cliff than you will by swimming in the cliff than you will by swimming in the sea there are you know other benefits to sea there are you know other benefits to sea there are you know other benefits to be be be gained um gained um gained um yeah I mean I think I I think that I yeah I mean I think I I think that I yeah I mean I think I I think that I think that's probably a reasonable think that's probably a reasonable think that's probably a reasonable discussion of the different levels of discussion of the different levels of discussion of the different levels of cold exposure and regarding the contrast cold exposure and regarding the contrast cold exposure and regarding the contrast method do you think that alternating method do you think that alternating method do you think that alternating back and forth between the SAA and cold back and forth between the SAA and cold back and forth between the SAA and cold immersion could adapt somebody to both immersion could adapt somebody to both immersion could adapt somebody to both heat exposure and cold exposure at the heat exposure and cold exposure at the heat exposure and cold exposure at the same time or might this be a bit like same time or might this be a bit like same time or might this be a bit like concurrent exercise training where what concurrent exercise training where what concurrent exercise training where what we see is that where you to do endurance we see is that where you to do endurance we see is that where you to do endurance exercise straight after resistance exercise straight after resistance exercise straight after resistance training then you might well blunt the training then you might well blunt the training then you might well blunt the adaptations to the resistance training

52:00adaptations to the resistance training adaptations to the resistance training yeah um very little been done uh and yeah um very little been done uh and yeah um very little been done uh and that which has suggests that there are that which has suggests that there are that which has suggests that there are components of both that can be adapted components of both that can be adapted components of both that can be adapted um so you should be able to adapt the um so you should be able to adapt the um so you should be able to adapt the cold shock response um even if you've cold shock response um even if you've cold shock response um even if you've gone into a I mean this is classic gone into a I mean this is classic gone into a I mean this is classic Scandinavian out of the sauna into the Scandinavian out of the sauna into the Scandinavian out of the sauna into the cold um there's evidence that the cold cold um there's evidence that the cold cold um there's evidence that the cold shock response is diminished by shock response is diminished by shock response is diminished by preheating because there's so much heat preheating because there's so much heat preheating because there's so much heat stored in the tissue that the the heat stored in the tissue that the the heat stored in the tissue that the the heat moving out from the body slows the rate moving out from the body slows the rate moving out from the body slows the rate of change of skin of the cold receptors of change of skin of the cold receptors of change of skin of the cold receptors so there's there's an attenuation of the so there's there's an attenuation of the so there's there's an attenuation of the cold shock response even though the the cold shock response even though the the cold shock response even though the the skin temperature doesn't um shows a very skin temperature doesn't um shows a very skin temperature doesn't um shows a very similar profile so I think um yeah I similar profile so I think um yeah I similar profile so I think um yeah I mean The Limited evidence there is and mean The Limited evidence there is and mean The Limited evidence there is and that's going right back into the 50s and that's going right back into the 50s and that's going right back into the 50s and 60s suggests that you can get some 60s suggests that you can get some 60s suggests that you can get some concurrent adaptation but it's not it's concurrent adaptation but it's not it's concurrent adaptation but it's not it's not as comprehensive as you get with a not as comprehensive as you get with a not as comprehensive as you get with a full-on Heat climatization program or full-on Heat climatization program or full-on Heat climatization program or full-on cold climatization program

53:00full-on cold climatization program full-on cold climatization program um I I I guess I mean the interesting um I I I guess I mean the interesting um I I I guess I mean the interesting thing about all of this is I and and maybe it's something we're is I and and maybe it's something we're going to come on to but it's why there going to come on to but it's why there going to come on to but it's why there is why there why these things are having is why there why these things are having is why there why these things are having a beneficial effect um you know why are a beneficial effect um you know why are a beneficial effect um you know why are we getting people claiming that um cold we getting people claiming that um cold we getting people claiming that um cold immersion is good for them and that it's immersion is good for them and that it's immersion is good for them and that it's changed their Liv life and their changed their Liv life and their changed their Liv life and their mentally they have you know both mentally they have you know both mentally they have you know both psychologically and physically um psychologically and physically um psychologically and physically um better uh and I and you know I think better uh and I and you know I think better uh and I and you know I think it's probably because of where we've got it's probably because of where we've got it's probably because of where we've got to as a species I was going to say what to as a species I was going to say what to as a species I was going to say what comes to mind is a combination of comes to mind is a combination of comes to mind is a combination of mindset effects where people are mindset effects where people are mindset effects where people are expecting beneficial effects of engaging expecting beneficial effects of engaging expecting beneficial effects of engaging in things like sea swimming and then in things like sea swimming and then in things like sea swimming and then also the fact that as you say bike also the fact that as you say bike also the fact that as you say bike people nowadays are relatively ther people nowadays are relatively ther people nowadays are relatively ther static and we need to challenge static and we need to challenge static and we need to challenge different organ systems in our bodies if

54:00different organ systems in our bodies if different organ systems in our bodies if we want to retain their functions over we want to retain their functions over we want to retain their functions over time especially as we get older I'd just time especially as we get older I'd just time especially as we get older I'd just like to ask a couple more questions like to ask a couple more questions like to ask a couple more questions about timing starting with thinking about timing starting with thinking about timing starting with thinking about the seasons obviously in the UK about the seasons obviously in the UK about the seasons obviously in the UK for example there are large fluctuations for example there are large fluctuations for example there are large fluctuations in ambient conditions from winter to in ambient conditions from winter to in ambient conditions from winter to summer do you think that it would make summer do you think that it would make summer do you think that it would make sense to focus more on heat exposure for sense to focus more on heat exposure for sense to focus more on heat exposure for somebody during the cold months of somebody during the cold months of somebody during the cold months of winter because they're going to get some winter because they're going to get some winter because they're going to get some cold exposure incidentally and then cold cold exposure incidentally and then cold cold exposure incidentally and then cold exposure during the warm months of exposure during the warm months of exposure during the warm months of summer so they're challenging both ends summer so they're challenging both ends summer so they're challenging both ends of their Thermo regulatory capacity yeah of their Thermo regulatory capacity yeah of their Thermo regulatory capacity yeah I mean it's something that's not been I mean it's something that's not been I mean it's something that's not been tested all we I mean just but it follows tested all we I mean just but it follows tested all we I mean just but it follows on from excuse me it follows on from on from excuse me it follows on from on from excuse me it follows on from what you've mentioned about I use the what you've mentioned about I use the what you've mentioned about I use the term thermostatic in in the editorial I term thermostatic in in the editorial I term thermostatic in in the editorial I wrote about you know humans being being wrote about you know humans being being wrote about you know humans being being too thermostatic that um what we used to too thermostatic that um what we used to too thermostatic that um what we used to do naturally which was get cold and get do naturally which was get cold and get do naturally which was get cold and get hot um during the course of pretty much

55:00hot um during the course of pretty much hot um during the course of pretty much every day we now don't do at all uh and every day we now don't do at all uh and every day we now don't do at all uh and and it's interesting that I mean not and it's interesting that I mean not and it's interesting that I mean not just in the sort of well-being area but just in the sort of well-being area but just in the sort of well-being area but also in the clinical area we're seeing also in the clinical area we're seeing also in the clinical area we're seeing lots of work now being published and lots of work now being published and lots of work now being published and we've done some of it one one of my we've done some of it one one of my we've done some of it one one of my colleagues Dr an Shepard is working in colleagues Dr an Shepard is working in colleagues Dr an Shepard is working in this area with Tom James um looking at this area with Tom James um looking at this area with Tom James um looking at the benefit of heat exposures for the benefit of heat exposures for the benefit of heat exposures for glucose sensitivity type 2 diabetes um glucose sensitivity type 2 diabetes um glucose sensitivity type 2 diabetes um we've we've talked about cold so I I we've we've talked about cold so I I we've we've talked about cold so I I mean I don't I don't know that there is mean I don't I don't know that there is mean I don't I don't know that there is any evidence to support your um you know any evidence to support your um you know any evidence to support your um you know your postulation but it seems to make your postulation but it seems to make your postulation but it seems to make Common Sense seems to be common sense Common Sense seems to be common sense Common Sense seems to be common sense that if we're in a situation where now that if we're in a situation where now that if we're in a situation where now we don't get any variations or very we don't get any variations or very we don't get any variations or very minimal variations that we have to minimal variations that we have to minimal variations that we have to artificially introduce those and in the artificially introduce those and in the artificially introduce those and in the winter that would be heat and in the winter that would be heat and in the winter that would be heat and in the summer that might be cold um because

56:00summer that might be cold um because summer that might be cold um because we're now having to artificially we're now having to artificially we're now having to artificially introduce things that one at one time introduce things that one at one time introduce things that one at one time happen naturally including driving to happen naturally including driving to happen naturally including driving to the gym to go and do some exercise which the gym to go and do some exercise which the gym to go and do some exercise which is part of that is a part of that is part of that is a part of that is part of that is a part of that overall picture of a species that has overall picture of a species that has overall picture of a species that has evolved techn technologically rather evolved techn technologically rather evolved techn technologically rather than than than physiologically and as such in order to physiologically and as such in order to physiologically and as such in order to perturb the systems we need to Main perturb the systems we need to Main perturb the systems we need to Main maintain functionality we have to maintain functionality we have to maintain functionality we have to artificially go and run on a treadmill artificially go and run on a treadmill artificially go and run on a treadmill or maybe artificially go to a saer or or maybe artificially go to a saer or or maybe artificially go to a saer or artificially go to have a swim in the artificially go to have a swim in the artificially go to have a swim in the cold water don't be that person that cold water don't be that person that cold water don't be that person that drives to the gym to walk on the drives to the gym to walk on the drives to the gym to walk on the treadmill nobody likes that person and treadmill nobody likes that person and treadmill nobody likes that person and then regarding time of day if you look then regarding time of day if you look then regarding time of day if you look at the incidence of cardiovascular at the incidence of cardiovascular at the incidence of cardiovascular events such as heart attacks then they events such as heart attacks then they events such as heart attacks then they tend to Cluster in the morning tend to Cluster in the morning tend to Cluster in the morning especially between about 6:00 a.m. and especially between about 6:00 a.m. and especially between about 6:00 a.m. and 12:00 p.m. we know that there are large 12:00 p.m. we know that there are large 12:00 p.m. we know that there are large circadian fluctuation in various circadian fluctuation in various circadian fluctuation in various different functions within the different functions within the different functions within the cardiovascular system there was a really cardiovascular system there was a really cardiovascular system there was a really nice paper published recently by David

57:00nice paper published recently by David nice paper published recently by David Beck told and his colleagues looking at Beck told and his colleagues looking at Beck told and his colleagues looking at Cadian rhythms within the Sino atrial Cadian rhythms within the Sino atrial Cadian rhythms within the Sino atrial and atrio ventricular nodes which seem and atrio ventricular nodes which seem and atrio ventricular nodes which seem to be driven by rhythms in the heart and to be driven by rhythms in the heart and to be driven by rhythms in the heart and brain and those might underly that time brain and those might underly that time brain and those might underly that time of day variation susceptibility to these of day variation susceptibility to these of day variation susceptibility to these events so I just curious about what your events so I just curious about what your events so I just curious about what your thoughts are on the best timing within thoughts are on the best timing within thoughts are on the best timing within the biological day for cold water the biological day for cold water the biological day for cold water immersion because so many people immersion because so many people immersion because so many people Advocate doing it in the morning Advocate doing it in the morning Advocate doing it in the morning sometimes in the face of sleep loss and sometimes in the face of sleep loss and sometimes in the face of sleep loss and cadium misalignment after waking to an cadium misalignment after waking to an cadium misalignment after waking to an alarm clock in the morning before work alarm clock in the morning before work alarm clock in the morning before work so that it improves their cognitive so that it improves their cognitive so that it improves their cognitive function which to me seems completely function which to me seems completely function which to me seems completely misguided so um in that introduction you misguided so um in that introduction you misguided so um in that introduction you probably introduced enough conversation probably introduced enough conversation probably introduced enough conversation for another hour um so where do we start for another hour um so where do we start for another hour um so where do we start with that um I've always been fascinated with that um I've always been fascinated with that um I've always been fascinated by Cadian Rhythm um if you allow people by Cadian Rhythm um if you allow people by Cadian Rhythm um if you allow people free run I you put them in an AP free run I you put them in an AP free run I you put them in an AP periodic environment we we tend to run

58:00periodic environment we we tend to run periodic environment we we tend to run on about a 25h hour clock um once you on about a 25h hour clock um once you on about a 25h hour clock um once you get free running you're much more get free running you're much more get free running you're much more susceptible to cooling and heating you susceptible to cooling and heating you susceptible to cooling and heating you don't defend the Deep body temperature don't defend the Deep body temperature don't defend the Deep body temperature enough so that these are really enough so that these are really enough so that these are really interesting areas that um that perhaps I interesting areas that um that perhaps I interesting areas that um that perhaps I mean you can reintroduce that mean you can reintroduce that mean you can reintroduce that periodicity by giving people food at periodicity by giving people food at periodicity by giving people food at certain time so you don't have to have a certain time so you don't have to have a certain time so you don't have to have a light dark cycle but it does become light dark cycle but it does become light dark cycle but it does become interesting when people get in a interesting when people get in a interesting when people get in a situation where they're in a a you know situation where they're in a a you know situation where they're in a a you know constant illuminated environment or constant illuminated environment or constant illuminated environment or they're in a a polar region which is they're in a a polar region which is they're in a a polar region which is dark etc etc the other thing again it dark etc etc the other thing again it dark etc etc the other thing again it comes back to this thing about which you comes back to this thing about which you comes back to this thing about which you touched on with the ice touched on with the ice touched on with the ice vest uh we are an integrated animal and vest uh we are an integrated animal and vest uh we are an integrated animal and what we do to ourselves will have a what we do to ourselves will have a what we do to ourselves will have a whole range of um impacts and sometimes whole range of um impacts and sometimes whole range of um impacts and sometimes we ignore some of the why because we're we ignore some of the why because we're we ignore some of the why because we're so so because the way we're educated and so so because the way we're educated and so so because the way we're educated and the way we have expertise we're all the way we have expertise we're all the way we have expertise we're all siloed so the Ice Fest yes you're siloed so the Ice Fest yes you're siloed so the Ice Fest yes you're absolutely right will cool the tissue absolutely right will cool the tissue absolutely right will cool the tissue which might initially look good but at which might initially look good but at which might initially look good but at the same time it's causing a cold

59:00the same time it's causing a cold the same time it's causing a cold diuresis um the other thing people diuresis um the other thing people diuresis um the other thing people forget is that when you get up in the forget is that when you get up in the forget is that when you get up in the morning you're doing exactly that you've morning you're doing exactly that you've morning you're doing exactly that you've just done a period of bed rest and when just done a period of bed rest and when just done a period of bed rest and when you're laying horizontal your fluid you're laying horizontal your fluid you're laying horizontal your fluid dynamics change um you know you start dynamics change um you know you start dynamics change um you know you start you you you're now you're now in a you you you're now you're now in a you you you're now you're now in a essentially you've done a a six or eight essentially you've done a a six or eight essentially you've done a a six or eight or 10 hour bed rest study where you're or 10 hour bed rest study where you're or 10 hour bed rest study where you're um you will reduced the amount of um you will reduced the amount of um you will reduced the amount of circulating blood volume you've got um circulating blood volume you've got um circulating blood volume you've got um because you've gone into a into a because you've gone into a into a because you've gone into a into a horizontal position as opposed to an horizontal position as opposed to an horizontal position as opposed to an upright position and now you go straight upright position and now you go straight upright position and now you go straight to an upright position you go into a um to an upright position you go into a um to an upright position you go into a um a bathroom and you Splash cold water on a bathroom and you Splash cold water on a bathroom and you Splash cold water on your face as part of um getting up in your face as part of um getting up in your face as part of um getting up in the morning well you know as a thermal the morning well you know as a thermal the morning well you know as a thermal physiologist there's I've got several physiologist there's I've got several physiologist there's I've got several alarm bells ringing um uh and so it alarm bells ringing um uh and so it alarm bells ringing um uh and so it wouldn't it doesn't surprise me that we wouldn't it doesn't surprise me that we wouldn't it doesn't surprise me that we see that peaking cardiac problem um see that peaking cardiac problem um see that peaking cardiac problem um around about that time when somebody's around about that time when somebody's around about that time when somebody's risen from being horizontal for8 hours

1:00risen from being horizontal for8 hours risen from being horizontal for8 hours has gone into a bathroom and have has gone into a bathroom and have has gone into a bathroom and have splashed a load of cold water on their splashed a load of cold water on their splashed a load of cold water on their face whilst breath holding while they do face whilst breath holding while they do face whilst breath holding while they do it now when should you do Therefore your it now when should you do Therefore your it now when should you do Therefore your cold water cold water cold water well you can again You' got to be very well you can again You' got to be very well you can again You' got to be very careful that we're not being a bit like careful that we're not being a bit like careful that we're not being a bit like nanny statish and we're like the fun nanny statish and we're like the fun nanny statish and we're like the fun placee but it does bother me that people placee but it does bother me that people placee but it does bother me that people are don't have anything like the amount are don't have anything like the amount are don't have anything like the amount of information they need to make smart of information they need to make smart of information they need to make smart decisions I don't want them not to go decisions I don't want them not to go decisions I don't want them not to go for their morning dip or go to their do for their morning dip or go to their do for their morning dip or go to their do their whatever they want to do but I their whatever they want to do but I their whatever they want to do but I just want them to be availed of as much just want them to be availed of as much just want them to be availed of as much information to do that safely um this is information to do that safely um this is information to do that safely um this is one of the reasons why we we published one of the reasons why we we published one of the reasons why we we published the paper on cold water therapies a the paper on cold water therapies a the paper on cold water therapies a recent paper in the British Journal of recent paper in the British Journal of recent paper in the British Journal of sports medicine um about how to do them sports medicine um about how to do them sports medicine um about how to do them by minimizing risk and also try to by minimizing risk and also try to by minimizing risk and also try to publish things publicize things like publish things publicize things like publish things publicize things like non- freezing cold injury so um for me I non- freezing cold injury so um for me I non- freezing cold injury so um for me I would be doing my cold water dip at the

1:01would be doing my cold water dip at the would be doing my cold water dip at the time when it's least likely to have a time when it's least likely to have a time when it's least likely to have a detrimental or negative effect on me and detrimental or negative effect on me and detrimental or negative effect on me and I think I'd probably want to make sure I think I'd probably want to make sure I think I'd probably want to make sure that I've been up and about for a couple that I've been up and about for a couple that I've been up and about for a couple of hours before I went and threw myself of hours before I went and threw myself of hours before I went and threw myself into cold water but you know who I have into cold water but you know who I have into cold water but you know who I have no evidence particularly for that and no evidence particularly for that and no evidence particularly for that and because I think actually the problem we because I think actually the problem we because I think actually the problem we see early in the morning with cardiac see early in the morning with cardiac see early in the morning with cardiac problems is that combination of getting problems is that combination of getting problems is that combination of getting up and getting a wet face um so I it up and getting a wet face um so I it up and getting a wet face um so I it comes back to comes back to comes back to the so in the in the paper I've just the so in the in the paper I've just the so in the in the paper I've just discussed we give advice for people who discussed we give advice for people who discussed we give advice for people who are want to take up um cold therapies we are want to take up um cold therapies we are want to take up um cold therapies we give advice for groups that want to give advice for groups that want to give advice for groups that want to provide the experience and we give the provide the experience and we give the provide the experience and we give the advice to doctors to screen people even advice to doctors to screen people even advice to doctors to screen people even then um you know with a proper everyone then um you know with a proper everyone then um you know with a proper everyone should have a make sure they're fit and should have a make sure they're fit and should have a make sure they're fit and healthy enough to do this thing uh and healthy enough to do this thing uh and healthy enough to do this thing uh and should have a proper medical even then should have a proper medical even then should have a proper medical even then people need to realize that that medical

1:02people need to realize that that medical people need to realize that that medical can't pick up all of the potential can't pick up all of the potential can't pick up all of the potential conditions that could end up with a you conditions that could end up with a you conditions that could end up with a you know catastrophic outcome when you go know catastrophic outcome when you go know catastrophic outcome when you go into cold water the most recent case into cold water the most recent case into cold water the most recent case I've been involved in has been a brain I've been involved in has been a brain I've been involved in has been a brain hemorrhage a 39y old young fit healthy hemorrhage a 39y old young fit healthy hemorrhage a 39y old young fit healthy guy who went and did a cold waterer guy who went and did a cold waterer guy who went and did a cold waterer exposure and 1 minute after leaving the exposure and 1 minute after leaving the exposure and 1 minute after leaving the water water water collapsed uh with uh in a ruptured collapsed uh with uh in a ruptured collapsed uh with uh in a ruptured aneurysm so you know that's going to be aneurysm so you know that's going to be aneurysm so you know that's going to be really difficult to pick up at your at a really difficult to pick up at your at a really difficult to pick up at your at a even you know a reasonable medical so even you know a reasonable medical so even you know a reasonable medical so this is not without risk so by all means this is not without risk so by all means this is not without risk so by all means do what you want to do but try and Avail do what you want to do but try and Avail do what you want to do but try and Avail yourself of the information and even if yourself of the information and even if yourself of the information and even if it's not a catastrophic risk like a it's not a catastrophic risk like a it's not a catastrophic risk like a burst burst burst aneurysm um it might be something like a aneurysm um it might be something like a aneurysm um it might be something like a prerov vascular damage that you that prerov vascular damage that you that prerov vascular damage that you that you'll notice more in later life um but you'll notice more in later life um but you'll notice more in later life um but you know you know you know once you once you've got all the once you once you've got all the once you once you've got all the information at your disposal and you've information at your disposal and you've information at your disposal and you've become educated in that way then it's up

1:03become educated in that way then it's up become educated in that way then it's up to you to make make a decision um a part to you to make make a decision um a part to you to make make a decision um a part of that and it's something which is a of that and it's something which is a of that and it's something which is a more modern phenomenon is uh you know more modern phenomenon is uh you know more modern phenomenon is uh you know when I when I was starting if you wanted when I when I was starting if you wanted when I when I was starting if you wanted to get information on something you went to get information on something you went to get information on something you went to a library you went through index to a library you went through index to a library you went through index Medicus and you got the peer-reviewed Medicus and you got the peer-reviewed Medicus and you got the peer-reviewed paper and you read it now I can go paper and you read it now I can go paper and you read it now I can go online and I can just type in cold water online and I can just type in cold water online and I can just type in cold water Therapies can get a whole host of um Therapies can get a whole host of um Therapies can get a whole host of um people who have no qualifications have people who have no qualifications have people who have no qualifications have very little understanding they might very little understanding they might very little understanding they might have done two or three immersions um you have done two or three immersions um you have done two or three immersions um you know swims themselves and are now know swims themselves and are now know swims themselves and are now setting themselves up as an expert in setting themselves up as an expert in setting themselves up as an expert in the field um just be aware generally uh the field um just be aware generally uh the field um just be aware generally uh about where where you get your about where where you get your about where where you get your information from uh and you know ask information from uh and you know ask information from uh and you know ask questions like how how many years have questions like how how many years have questions like how how many years have you studied this how how many you studied this how how many you studied this how how many Publications do you have in this area Publications do you have in this area Publications do you have in this area because I do worry that you know we've because I do worry that you know we've because I do worry that you know we've got people screaming into cameras go got people screaming into cameras go got people screaming into cameras go anyone can do this uh and as I say at anyone can do this uh and as I say at anyone can do this uh and as I say at the same time we've got the death rate

1:04the same time we've got the death rate the same time we've got the death rate increasing and we've got the rescue raid increasing and we've got the rescue raid increasing and we've got the rescue raid increasing I was interacting with a increasing I was interacting with a increasing I was interacting with a chatbot recently that was based on a chatbot recently that was based on a chatbot recently that was based on a large language model that had pulled large language model that had pulled large language model that had pulled data from a popular podcast and just out data from a popular podcast and just out data from a popular podcast and just out of curiosity I asked it a few questions of curiosity I asked it a few questions of curiosity I asked it a few questions about the potential risks of cold water about the potential risks of cold water about the potential risks of cold water immersion and it couldn't give me a immersion and it couldn't give me a immersion and it couldn't give me a coherent answer so I think the that coherent answer so I think the that coherent answer so I think the that you're doing in science communication is you're doing in science communication is you're doing in science communication is so important and you've done some so important and you've done some so important and you've done some terrific work in everything from the terrific work in everything from the terrific work in everything from the popular media to podcasts like this so popular media to podcasts like this so popular media to podcasts like this so keep up that good work and sure enough keep up that good work and sure enough keep up that good work and sure enough the next question that I was going to the next question that I was going to the next question that I was going to ask you is about that bjsm paper and ask you is about that bjsm paper and ask you is about that bjsm paper and just whether you could just finish with just whether you could just finish with just whether you could just finish with a a few quick pieces of advice for a a few quick pieces of advice for a a few quick pieces of advice for people who want to try and stay safe people who want to try and stay safe people who want to try and stay safe during the Cold Water immersion that during the Cold Water immersion that during the Cold Water immersion that they engage in because they do really they engage in because they do really they engage in because they do really enjoy that particular activity and maybe enjoy that particular activity and maybe enjoy that particular activity and maybe also within that could you just mention also within that could you just mention also within that could you just mention a couple of absolute contraindications a couple of absolute contraindications a couple of absolute contraindications or relative contraindications to that or relative contraindications to that or relative contraindications to that type of activity contraindications uh

1:05type of activity contraindications uh type of activity contraindications uh which should be picked up by a medical which should be picked up by a medical which should be picked up by a medical screen remember a tropical animal going screen remember a tropical animal going screen remember a tropical animal going to cold water is probably the most to cold water is probably the most to cold water is probably the most severe stress you can place on the body severe stress you can place on the body severe stress you can place on the body and you wouldn't go out by a pair of and you wouldn't go out by a pair of and you wouldn't go out by a pair of running shoes and and go straight into a running shoes and and go straight into a running shoes and and go straight into a marathon you know you would make sure marathon you know you would make sure marathon you know you would make sure that you were fit enough and had done that you were fit enough and had done that you were fit enough and had done the training and did it incrementally the training and did it incrementally the training and did it incrementally and got to the point where you could do and got to the point where you could do and got to the point where you could do that um so that um so that um so anybody with um a family history of anybody with um a family history of anybody with um a family history of sudden or unexplained cardiac death sudden or unexplained cardiac death sudden or unexplained cardiac death hypertension like blood pressure cardiac hypertension like blood pressure cardiac hypertension like blood pressure cardiac R um um R um um R um um dismas um people esic heart dismas um people esic heart dismas um people esic heart disease um Long QT syndrome we've disease um Long QT syndrome we've disease um Long QT syndrome we've mention peripheral vascular disorders mention peripheral vascular disorders mention peripheral vascular disorders history of history of history of seizures um history of um you know seizures um history of um you know seizures um history of um you know family history of family history of family history of aneurisms uh any other Co morbidities aneurisms uh any other Co morbidities aneurisms uh any other Co morbidities people who are on various drugs for um

1:06people who are on various drugs for um people who are on various drugs for um conditions all of these are red flags conditions all of these are red flags conditions all of these are red flags for going and putting yourself into a for going and putting yourself into a for going and putting yourself into a situation where you're going to put a situation where you're going to put a situation where you're going to put a significant strain on the cardiovascular significant strain on the cardiovascular significant strain on the cardiovascular system and the respiratory system but system and the respiratory system but system and the respiratory system but particularly for the health side of particularly for the health side of particularly for the health side of things it's going to be the things it's going to be the things it's going to be the cardiovascular cardiovascular cardiovascular system um if you've got the all clear system um if you've got the all clear system um if you've got the all clear and you wanted to go about it go about and you wanted to go about it go about and you wanted to go about it go about it in an incremental fashion uh so it in an incremental fashion uh so it in an incremental fashion uh so you've got your medical um checkup you've got your medical um checkup you've got your medical um checkup you've avoided concurrent stresses and you've avoided concurrent stresses and you've avoided concurrent stresses and medications um make sure you swim with a medications um make sure you swim with a medications um make sure you swim with a group preferably on a lifeguarded beach group preferably on a lifeguarded beach group preferably on a lifeguarded beach but with people who know what they're but with people who know what they're but with people who know what they're doing I do a lot of work with the blue doing I do a lot of work with the blue doing I do a lot of work with the blue tits uh excellent group who are trying tits uh excellent group who are trying tits uh excellent group who are trying to get people to do Open Water Swimming to get people to do Open Water Swimming to get people to do Open Water Swimming that want to do it but in a very safe that want to do it but in a very safe that want to do it but in a very safe way there's lots of advice on their way there's lots of advice on their way there's lots of advice on their website about doing things safely make website about doing things safely make website about doing things safely make sure you know weather forecast you sure you know weather forecast you sure you know weather forecast you analyze the swimming location analyze the swimming location analyze the swimming location follow an incremental approach it's not follow an incremental approach it's not follow an incremental approach it's not um an embarrassment to wear a wet suit

1:07um an embarrassment to wear a wet suit um an embarrassment to wear a wet suit wear a wet suit if you want we know from wear a wet suit if you want we know from wear a wet suit if you want we know from studies that we've done that you'll get studies that we've done that you'll get studies that we've done that you'll get just as much benefit from wearing a wet just as much benefit from wearing a wet just as much benefit from wearing a wet suit as you will without um in terms of suit as you will without um in terms of suit as you will without um in terms of that that first couple of that that first couple of that that first couple of minutes habituate to the cold we've minutes habituate to the cold we've minutes habituate to the cold we've talked about how you might do that but talked about how you might do that but talked about how you might do that but do that you don't don't do that on your do that you don't don't do that on your do that you don't don't do that on your own again do that in a supervised way uh own again do that in a supervised way uh own again do that in a supervised way uh wear a visible hat a toe float um you wear a visible hat a toe float um you wear a visible hat a toe float um you got to uh enter the water slowly the got to uh enter the water slowly the got to uh enter the water slowly the cold chop response is both temporal and cold chop response is both temporal and cold chop response is both temporal and spatial summation so the slower you go spatial summation so the slower you go spatial summation so the slower you go in the smaller the response get used get in the smaller the response get used get in the smaller the response get used get your breathing under control before you your breathing under control before you your breathing under control before you start swimming swim parallel to the start swimming swim parallel to the start swimming swim parallel to the shore so that if you become shore so that if you become shore so that if you become incapacitated in any way you can just incapacitated in any way you can just incapacitated in any way you can just stand up you've not found yourself 200 M stand up you've not found yourself 200 M stand up you've not found yourself 200 M offshore people have made that mistake offshore people have made that mistake offshore people have made that mistake um avoid prolonged breath holds um um avoid prolonged breath holds um um avoid prolonged breath holds um Associated particularly with face Associated particularly with face Associated particularly with face immersion um limit your exposure to 10 immersion um limit your exposure to 10 immersion um limit your exposure to 10 minutes I see absolutely no reason for minutes I see absolutely no reason for minutes I see absolutely no reason for the vast majority of people to stay in the vast majority of people to stay in the vast majority of people to stay in for more than 5 or 10 minutes the for more than 5 or 10 minutes the for more than 5 or 10 minutes the benefit I believe has been accured by

1:08benefit I believe has been accured by benefit I believe has been accured by then if there you know of of the of the then if there you know of of the of the then if there you know of of the of the speculative benefits and hypothesized speculative benefits and hypothesized speculative benefits and hypothesized benefits definitely don't rely on how benefits definitely don't rely on how benefits definitely don't rely on how you feel um with cold habituation you you feel um with cold habituation you you feel um with cold habituation you you essentially disable your Behavioral you essentially disable your Behavioral you essentially disable your Behavioral or perceptual Thermo regulatory system or perceptual Thermo regulatory system or perceptual Thermo regulatory system so you've got people who when they're so you've got people who when they're so you've got people who when they're cold habituated can swim to the point of cold habituated can swim to the point of cold habituated can swim to the point of unconsciousness that happened to unconsciousness that happened to unconsciousness that happened to probably the most famous Open Water probably the most famous Open Water probably the most famous Open Water swimmer of his generation Jason zurgo swimmer of his generation Jason zurgo swimmer of his generation Jason zurgo studied by Griff Pew who when trying to studied by Griff Pew who when trying to studied by Griff Pew who when trying to swim from Ireland to Scotland um and the swim from Ireland to Scotland um and the swim from Ireland to Scotland um and the north Channel died about a mile or two north Channel died about a mile or two north Channel died about a mile or two from the Scottish Coast having cooled to from the Scottish Coast having cooled to from the Scottish Coast having cooled to the point of ventricular fibrillation the point of ventricular fibrillation the point of ventricular fibrillation without actually ever feeling cold um so without actually ever feeling cold um so without actually ever feeling cold um so don't rely on how you feel rely on time don't rely on how you feel rely on time don't rely on how you feel rely on time um 5 to 10 minutes max um if you get in um 5 to 10 minutes max um if you get in um 5 to 10 minutes max um if you get in trouble turn over float on your back um trouble turn over float on your back um trouble turn over float on your back um if you've go into the water and you're if you've go into the water and you're if you've go into the water and you're suffering cold shock float on your back suffering cold shock float on your back suffering cold shock float on your back that all comes from our research on the

1:09that all comes from our research on the that all comes from our research on the cold shock response and that's been cold shock response and that's been cold shock response and that's been taken up by the rnli we work very taken up by the rnli we work very taken up by the rnli we work very closely with the rnli on the float to closely with the rnli on the float to closely with the rnli on the float to live campaign you can just Google that live campaign you can just Google that live campaign you can just Google that and find out more about that um and and and find out more about that um and and and find out more about that um and and just remember that when you leave the just remember that when you leave the just remember that when you leave the water even if it's just 5 or 10 minutes water even if it's just 5 or 10 minutes water even if it's just 5 or 10 minutes you need to warm up properly uh and make you need to warm up properly uh and make you need to warm up properly uh and make sure that you've got some blood flow sure that you've got some blood flow sure that you've got some blood flow back to the extremities before you start back to the extremities before you start back to the extremities before you start we talked about um manual dexterity and we talked about um manual dexterity and we talked about um manual dexterity and manual function what happens in a lot of manual function what happens in a lot of manual function what happens in a lot of times is people come out of the water times is people come out of the water times is people come out of the water and they jump in their car and they and they jump in their car and they and they jump in their car and they start driving and what bothers me start driving and what bothers me start driving and what bothers me they're probably driving at the time they're probably driving at the time they're probably driving at the time where they're most physically disabled where they're most physically disabled where they're most physically disabled that they've been all day depending on that they've been all day depending on that they've been all day depending on how long they've been in the water it how long they've been in the water it how long they've been in the water it might be just a a peripheral disability might be just a a peripheral disability might be just a a peripheral disability but it might also be that they've got but it might also be that they've got but it might also be that they've got some Central cooling so some of their some Central cooling so some of their some Central cooling so some of their decision complex decision- making is decision complex decision- making is decision complex decision- making is impaired I haven't done a study to look impaired I haven't done a study to look impaired I haven't done a study to look at the number of car accidents driving at the number of car accidents driving at the number of car accidents driving back from um Open Water swimming but back from um Open Water swimming but back from um Open Water swimming but there's an interesting um question to be there's an interesting um question to be there's an interesting um question to be asked there we're doing the study

1:10asked there we're doing the study asked there we're doing the study looking at the impact on driving looking at the impact on driving looking at the impact on driving performance using a driving simulator at performance using a driving simulator at performance using a driving simulator at the moment but that's not yet been the moment but that's not yet been the moment but that's not yet been published and you can see all of that in published and you can see all of that in published and you can see all of that in the be British Journal sports medicine the be British Journal sports medicine the be British Journal sports medicine paper and I will link to that paper and paper and I will link to that paper and paper and I will link to that paper and several other papers that you've several other papers that you've several other papers that you've mentioned as well so I'll just end by mentioned as well so I'll just end by mentioned as well so I'll just end by saying thank you so much for your time saying thank you so much for your time saying thank you so much for your time today and I think the work that you do today and I think the work that you do today and I think the work that you do is going to be increasingly important is going to be increasingly important is going to be increasingly important important as time goes on too as climate important as time goes on too as climate important as time goes on too as climate becomes more extreme because I know that becomes more extreme because I know that becomes more extreme because I know that we focused on cold water immersion today we focused on cold water immersion today we focused on cold water immersion today but you're interested in extreme but you're interested in extreme but you're interested in extreme environmental physiology in general so environmental physiology in general so environmental physiology in general so keep up the great work and I realize keep up the great work and I realize keep up the great work and I realize we've gone 10 minutes over so you've we've gone 10 minutes over so you've we've gone 10 minutes over so you've been very generous and I look forward to been very generous and I look forward to been very generous and I look forward to what comes out of your lab in the near what comes out of your lab in the near what comes out of your lab in the near future lovely okay well it's been lovely future lovely okay well it's been lovely future lovely okay well it's been lovely to talk to you Greg and um thanks for to talk to you Greg and um thanks for to talk to you Greg and um thanks for the invitation

Cold Water Immersion Benefits and Risks Professor Mike Tipton MBE Reason Wellbei