00:00Are saunas good for you? Do they actually improve longevity? Maybe; depends on who you ask. I'll cover a key article in this space from 2015 in this video and then (excuse me) and then cover a follow-up article from the same authors in 2018 but let's start off the debate by reading an editorial letter - letter to the editor from the first article published in 2015. Laukkanen and colleagues note an association between increased frequency of sauna bathing and decreased risk of adverse cardiovascular events. Their observational study - and this is a key item, this is one of the critical points that you'll see through the raft of criticisms of this study; it's not so much a criticism of the study but a
01:00position on the debate that "Look, this is an observational study. It's not a randomized clinical trial." What's the difference? Well, a random - in a randomized clinical trial, the key word is randomized so if we did a randomized clinical trial for saunas, for example, we would take a large population and we would randomize who got sauna and who did not. An observational study on the other hand is looking at a large group of people who've made their own decisions. Some have said "I'm gonna have a sauna"; Some have said "I'm not" Now, why is that important? Again, we'll talk about that later as we get into this - to this debate; their observations - back to the - to the letter to the editor, their observational study does not establish that sauna bathing causes better cardiac health rather their results may be due to self selection. Persons at higher risk
02:00for adverse cardio - cardiac events may experience unpleasant symptoms due to the tachycardia thats induced by sitting in a hot sauna such as mild dyspnea, orthostasis, chest discomfort, power frequency or severity of persons - than persons in good health. Now, really - yes these are saunas that what? go to what is it? 75 degrees or a hundred degrees centigrade. Anyhow, something closer to 150 degrees and more to maybe up to 200 degrees Fahrenheit - so these are very hot and, again, that's what the - the one of the positions of those that would argue that saunas really are - the sauna studies are a self-selection observational study rather than something looking at - do saunas actually
03:00impact health in and out of themselves? Now, this is - I have to admit - this is an interesting time to - to be looking at this. This is the article itself but let me just go back and make a point about the timing. Right now, it's January 30 - late January 2019 and we have one of our coldest snaps in - in memory. Coming through the East Coast, so I also recently happened to move back to Lexington Kentucky and we happen to be less than one block from the local YMCA. So it's an interesting item for me and for my own decisions about whether I do a sauna, in the beginning I read this article and I said "You know what? I'm gonna make sure and do a sauna three times a week. At least 20 minutes per - per session." Now, as I get a little bit deeper
04:00into it - not quite so sure but again that's something we'll talk about later. The title of the original article is in, again, JAMA internal medicine April 2015 Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events; Tanjaniina Laukkanen, Hassan - Hassan Khan and Francesco Zaccardi; and the - the chief studier was also our - the principal investigator; so what we call it (pardon the hesitation at senior moment - moment over - over the term) the principal investigator was a doctor - I think Holly Laukkanen, and I don't know if there was a relationship between him and Tanjaniina. Anyway, as I said, the timing is
05:00interesting. Now, I got hooked into this debate by watching Dr. Rhonda Patrick. I know that many of my viewers have seen Dr. Patrick on a recent related video on heat shock proteins. I mentioned where probably a dozen of my viewers and comment boxes have mentioned Dr. Patrick. Now, that's actually where I learned about heat shock proteins - proteins that manage the - they called chaperones or - of other proteins. They help other proteins form geometrically - correctly when they're forming; if they get denatured through something like heat denatured means loss of the geographic components of the protein. Heat shock proteins can
06:00help - help reform them and they can also - because they manage these proteins and how they are set up in space, they also present them for autophagy to lysosomes and they present them for antigen recognition within immune system functions. So a lot of different very interesting components. It - yes, your body does; there's been research which I'll mention it - I think at the end of this video, which shows that - Yes, your body does make these heat shock proteins as a result of heat stress and yes, these proteins have been associated with significant health impacts. Now, as I mentioned - they help the protein fold and form the correct areas in space; the correct geometry. Dr.
07:00Patrick also went on to talk about FoxO3 and, again, I'll do a separate video on FoxO3 which she would call the longevity gene, in terms of its impact on DNA repair, and some other things; But, again, back to the - to the debate around that JAMA article of 2015; Here's another - actually, that article and JAMA internal medicine got pilloried - I think - with these types of letters. Here's another one, from Yoram Epstein and Yahuda Shoenfeld - The Link Between Sauna Bathing and Mortality may be non-causal; In other words, A causes B. They - may be they're saying wait a minute, this may be A causes both B and C; and - or C causes both A and B. What does that mean? Well, let's - let's read the article.
08:00Read the first parts of the letter. In their recent report, Laukkanen & Associates summarized a 25-year longitudinal study indicating the regular sauna bathing; Laukkanen, by the way, is a cardiologist in Finland; so he knows his culture around saunas. Regular sauna bathing 4 - 7 times per week is associated with a reduced risk of cardiovascular diseases and even all cause mortality. That's a big deal, as - as I did a video on all cause mortality and and waiting for something to show a change in all-cause mortality before you agree that it's a worthwhile treatment; The problem with waiting for all-cause mortality changes is this - there are just too many different causes of death and even cardiovascular death is as prominent as it - as it is;
09:00It's like what? a third; it automatically gets watered down by a factor of three when you're trying to look at a treatment to see if it actually improves all cause mortality. So things get watered down too much. This one didn't. It showed an impact in all cause mortality. If people sat in a sauna for at least what? and, again, there was a dose-response curve which we'll talk about a little bit later, once we talk about study. I'm getting a little bit ahead of myself and thanks for your patience if you're hanging in there with me. Now, Epstein and Shoenfield are saying "We would like to suggest that regular sauna bathing is an indicator for a healthy lifestyle" In other words, C (healthy lifestyle) causes both A (sauna use) and B (cardiovascular longevity); adopting habits of frequent
10:00physical activity, avoiding rich food high in saturated fat. Well, you know that's their perspective. a lot in folks don't agree with that but frequent physical activity keeping your weight down, etc. and - let me, it may be easier for me to just put this in personal terms; I recently moved - Janice and I recently moved back to Lexington from from Nashville. We happen to move less than half a block from the local YMCA. Now, if I go to the YMCA and sit in one of these sauna - they've got a great sauna that - well, it's - it's small and crowded but it's a hot sauna; and if I go to that sauna and sit there for 20 minutes, three times a week; is that going to make me healthy? or is the fact that I've kept my B - I keep my BMI down to the low 20s, that I
11:00watch my carbs, I - I'm very aggressive about managing insulin resistance and that I exercise with resistance training, high intensity intervals and - and now even some - back to some long slow distance; are those things impacting my cardiovascular risk or is the sauna? and again, these guys would say it's those things, not the sauna. What would I say? Actually, I think it's probably a little of both, but again, I'm getting ahead of myself. Let's go to the article itself; so this was the article - 2015 like I said Tanjaniina Laukkanen and Jari Laukkanen, MD, PhD, cardiologist in Finland; who is the principal investigator of this in this study. Now,
12:00the objective was to look at the relationship between sudden cardiac death, coronary heart disease, and alcohol, and sauna use - frequency and duration. What they did - there's a registry of - of heart disease patients in Kuppio, Finland. There were 2,315 middle-aged men, 42 to 60 years, from eastern Finland; baseline examines - examinations were done between March '84 and December '89. They surveyed these guys - regarding their sauna use. There's a median follow-up of 20.7 years. Now, here's where we get into the dose response curve, and I mentioned that earlier; A dose response curve is incredibly powerful from an epidemiological perspective. Why is that?
13:00and - and what is it? So here - first, let's talk about what it is with this group - The numbers of sudden cardiac deaths were 61, 119, and 10 in the 3 groups of the frequency of sauna bathing; the respective numbers were 89, 175, and 17 for fatal coronary heart deaths; 134 - Oh well, let's go back and look at percentages - 10.1%, 7.8%, and 5%; the percentages in terms of fatal coronary heart disease were 15%, 11%, and 8.5%; for fatal cardiovascular deaths 22%, 16% and 12%; Now, what are
14:00those percentages and how did they create a dose response curve? Well, they're one time per week, two times per week, and four to seven times per week. In other words, in all of these categories, including all cause mortality, the more the guys that went the least had the highest death rates, and the guys that went the most and the guys that stayed in there the longest per session, all had the lowest cardiovascular death rates and all cause mortality rates. Again, maybe I gave away the store when I talked about the argument regarding this issue because, again, a lot of folks got very, very excited about this article and saunas became a big deal and still are with a lot of people. Now, the question is -
15:00which is it? Okay, so his conclusions and relevance - Increased frequency of sauna bathing is associated with a reduced risk of cardiac symptoms, cardiac death and even all cause mortality. As I mentioned before, we have looked - there's been more investigation into this issue; things like looking at heat shock proteins, and certainly those heat shock proteins are created in response to something like a sauna. Now, a couple of other points about this - how hot is it? This is not just a jacuzzi; This is 175 - 200 degrees Fahrenheit. As I mentioned regarding the dose-response curves, the more frequently you use the
16:00sauna, the lower your death rate. These are death rates for sudden cardiac death and, again, much lower for people that were using it a lot. Also, the same thing regarding the amount of time you were in it. These were the people that were in a less than 11 minutes, and again, the steeper the curve, the more - the higher the death rate; 11 - 19 minutes in the middle, and greater than 19 minutes per session, the lowest death rate here down at the bottom; So, again, some very interesting components, some very interesting perspectives in debate. There's no question that, in this study in Finland, that the people that used sauna
17:00is more - were far - had far greater longevity; Now, here's the question though: Was it due to the saunas or was it due to something else? So I just wanted to add this as an addendum to - to this video. I was able to go back and find a follow-up article, I had mentioned it before and said I would do that in the next video, as I get deeper into reviewing that article. It doesn't look worth another video to me and here's why. I - I found it, read the abstract, and I went here: PMID; you can use that number and go find the - the home of the article, and I did and it was Elsevier. You may remember I've mentioned Elsevier articles in several other areas.
18:00Basically, they have a very strong paywall and so they put this article behind the paywall - 55 bucks for me to get that full article. If there's a whole lot of real, deep interest and comments regarding it, I may invest and go ahead and do it but let's go back and just look at the abstract. This one is basically saying "Look, combined effect of sauna breathing - sauna bathing and cardiovascular respiratory fitness on the risk of sudden cardiac deaths in Caucasian men; a long-term prospective cohort study." Again, pardon me for jumping around, but I have to make the comment if this had been a couple of comments - if this had been earth-shaking and seen as very, very important - they probably could
19:00have gotten this back in as a follow-up within the JAMA internal medicine; and I actually have no doubt; I expect that they probably did submit this as a another article with JAMA internal medicine. My guess is that the JAMA editors felt a couple of things. Number 1 - that maybe this was not such incredible science that they did they did in this one; and number 2 - they probably felt like they got beat up and pilloried in terms of responses and letters from the original article and they may have felt a little bit embarrassed that they didn't see this whole observational, environmental concern. Either way, they didn't publish it and, right now, I'm not going to pay to go past the pay wall to get into the details of this study but here's
20:00what they said - they looked at - remember the - the question was our observational study: Was it the fact that these people were the people that used saunas, who more often and longer per session were people that were already in cardiovascular shape, and they could therefore stand it and they were, therefore, motivated to do it because there were people that were already making efforts to stay in shape? So here's what this article says "Look, we looked at both of those - the effect of sauna bathing on cardi arrest and cardiorespiratory fitness." Now, what they're saying here is they're independently associated with sudden cardiac death, meaning both in and of themselves are independently associated. Now, how did they do that? They went back and did what's called a multiple hazards - multiple - multi-variable analysis; They're
21:00several ways, statistically, to go in and look and see "Okay, where are men that have good cardiovascular conditioning but don't spend a lot of time in the sauna?" and "Where are men that have poor - poor cardiovascular conditioning but are - but are staying longer in the sauna?" So basically, you end up with - with what we call a two by two table: people that are well conditioned and spent a lot of time in the sauna versus people that are poorly conditioned and spent a lot of time in the sauna; and people that are well conditioned but don't spend much time in the sauna and people that are well conditioned and do spend a lot of time so - and don't. The - the point is - once
22:00you get that kind of two-by-two analysis, you can go back and make a little bit deeper focus on which of these two - is there something that's causing both of these? In other words, is there a complete one-to-one ratio between fitness, sauna use, and cardiac death and/or is there separation between the two? And that's what they did; they just did a - the multivariate analysis using, basically the same population. Now, that's yet another clue regarding why they didn't get this follow-up study in - in the - the higher prestige, higher impact journal JAMA. It's because they should have done that in the original study and guess what? The editors of JAMA should have noticed that in the original study and they should have forced that analysis before they printed the article.
23:00Again, they were embarrassed. Now, what does that mean for us though? That's a lot of epidemiology, may be political, academic political arguments. What is it? What it means though, assuming this analysis is correct, is that yes, it does help. Saunas do help. Now, it doesn't go into why and if we want to go back into why, we may need to go back and watch some of Rhonda Patrick's videos, Thank you very much for your interest.