This Simple Sauna Mistake Increases Dementia Risk — Dr. Rhonda Patrick
00:00So let me ask you about two other things related to brain health since this is on on the mind. Uh for the first is related to saunas and the second one is vitamin D. So with saunas I was looking back and I think this is probably summarized by some LLM. So, I want to be very careful with citing numbers, but I'm looking at a summary, I believe, of the findings of a large Finnish study published in JAM Internal Medicine 2015 that followed 2,000 middle-aged men for 20 years. That's wild. And it looks like, please correct me if if from memory you can correct any of this, but all callers of mortality 24% lower risk with two to three times per week. This is sauna use. and four to seven times per week was associated with 40% lower risk. And I'll just cut to the one that's of greatest interest to me right now. Says in a follow-up paper, using this on a four to seven times per
01:00week was associated with a 66% lower risk of dementia and 65% lower risk of Alzheimer's. Now, at face value, if those numbers are roughly accurate, those numbers seem incredible, right? And I guess what I'm wondering is how should we think about those results? Because if out of a 100 people two people were getting dementia and now it's one person, it's less interesting than other ways of interpreting the data. How should we think about this? And how do you personally use if you do sauna or hot tub or heat stress at this point? >> Those numbers are accurate by the way. They're spot on. >> And there is a dose dependence there which kind of strengthens the data, right? So people that are using this on it more frequently are having a more robust effect. You mentioned 24% lower all cause mortality and then 40% if they're doing two to three times a week versus four to seven times a week they're they're having a 40% lower all
02:00cause mortality. And the dementia risk is also extremely interesting to me. And this goes back Tim to like some of the earliest experiments that I did as a sort of budding young biologist at the Sulkq Institute where I was working with these little nematode seligans worms and injecting human amaloid beta 42 into these worms and essentially injecting it into their muscle so that they become basically the amaloid beta 42 aggregates and forms these aggregates as these worms age and it happens very rapidly cuz their life expectancy is only 15 days within like day or so they start to become paralyzed where they can't move their lower half or their muscles their mus muscular cells are and they can only move their nose to feed in this little petri dish with ecoli bacteria which is what they eat. I would do these experiments and then I would overact basically where you do a genetic manipulation and you can make them overexpress heat shock proteins which
03:00are something that are robustly activated upon heat stress as the name implies and sauna has been shown to activate heat shock proteins. If you're in the 163° Fahrenheit sauna for around 30 minutes, you can activate your heat shock proteins by 50% more than baseline. So when I would add, you know, heat shock proteins that would be activated in these worms, it would prevent this from happening. These protein aggregates don't happen. And that's because one of the things that heat shock proteins do is they help repair damaged proteins that are misfolded and prevent them from aggregating. And so you want to have more active heat shock proteins if you're wanting to prevent Alzheimer's disease. Now, there's a lot of animal studies that have shown this as well. For example, you can take a mouse and sort of give it Alzheimer's disease. in this in a similar way and if they have a lot of active heat shock protein genes then they're not getting the Alzheimer's disease it delays it right I remember reading this study and it was like one of the things I was thinking about was of course you know the heat shock proteins are activated upon the sauna use that you would probably see a lower
04:00incidence of Alzheimer's disease and even dementia there's other things as well cardiovascular health is really improved with the sauna so sauna sort of mimics moderate intensity exercise and so if you're having improved cardiovascular health that means more blood flow to the brain. Lots of things are happening, right? The one thing I do want to mention, Tim, and this is this study was I think it came out in 2020ish. I don't remember the exact year, but it was not out of Finland. I believe it was a Polish study. >> Mhm. >> And that study looked at sauna use and dementia risk. And there was very interesting results there. So they sort of looked at people that were using saunas but they also sort of categorized them based on the amount of heat. So how hot their saunas got. >> So in the Finnish studies in Adam Finland, >> majority of the people are using the sauna at around equivalent of 174° F. >> That's about what the average temperature of pretty much any of those
05:00studies that you cited. That's about the average temperature that they're using them and they're in there for about 20 minutes. >> Mhm. Now, this other study looked at a wide range of different temperatures, that temperature versus like the really, really high extreme end. So, people that were doing like 200 degrees Fahrenheit or more. And this is something that you can see nowadays, like there's this sort of, >> you know, go all in, go hard or go home, right? And so, people think that they need to go in a 200° sauna, and if they go in a 200°ree sauna, it's going to be better than going in a 175° Fahrenheit sauna, right? >> Apparently not the case. In that study, again, you saw a protective effect of people that used the sauna, and I think it was also dose dependent, but I can't recall. There was a protective effect, but only if they used saunas that were less than 190° F. >> Huh. >> People that started going into the 190° to 200° F range actually had an increased risk. >> Oh, no. >> So, that was something that I don't know that anyone talks about. >> But, you know, I've done really, really hot saunas before. I personally don't
06:00like it. I get headaches actually. Yes. >> So, you know, your head is in there and you have to think about that your head is getting heated up. >> And so, I don't know that it's necessarily good to go in a 212 degree Fahrenheit sauna. >> You know, for your head. Now, I don't want to say, you know, that with certainty because there could be all kinds of confounding factors, but it's something to keep in mind. And why do you have to go above 190? 190 is hot as hell. That's good enough. Like, you don't have to go above that. >> My default setting of my son is 194. So, it's just kind of like, well, I guess I set it some time ago. So, it's just been set at 194. So, that's sort of my default. So, maybe I want to maybe I want to dial it back. >> I think 190 is great. >> Yeah, >> 190 is great. You asked about me and how I use the sauna. Now, I should also mention that hot tubs are are good as well. And in fact, a study just came out a few weeks ago showing that hot tubs have, you know, comparable effects on blood pressure regulation. All these parameters that are looked at with sauna use as well. And a lot of people ask that question, you know, oh, what about a hot tub or a hot bath? And I think,
07:00you know, not everyone has access to a sauna, not everyone has access to a hot tub, but a lot of people have access to a hot bath. >> And I think if you can get a sort of pool thermometer and keep the temperature of your bath 104 degrees Fahrenheit, which is what all the studies use, >> you have to keep adding hot water. That's fine. >> It's pretty hot. >> Yeah, it's pretty hot. You stay in there for about 20 minutes and you're going to have comparable effects. You'll be sweating like you're in a sauna. Don't worry about it. >> Exactly. >> 104. >> 104 is hot. And I actually do both. I do a hot tub and I do sauna. I like to do hot tub at night. It does seem to help with my sleep and sometimes, but sometimes I'll do the sauna in the day and I'll do it after a workout. It sort of extends my workout. I particularly like doing them after a workout like in the winter when it's cold and if I work out outside. >> So that's kind of how I use the sauna. I was doing hot tubs for a while like every night. I don't do that in the summer because it's just hot. I actually shift more to cold doing cold exposure more in the summer, which is kind of funny. Pretty much the only time I do it
08:00is in the summer. I'm such a wuss. I like doing the heat a lot in the in the winter. >> I would be very curious to see if, you know, they measured like sperm motility and morphology for all the males who are doing this and they're like, "Good news, you have this incredibly lowered risk of Alzheimer's. Bad news. You're effectively sterile from all the heat on your on your swimmers. >> Good point. There's been studies that have shown you do lower motility for sure. The motility rates lowered and that those changes are reversed after 6 weeks of abstaining. So, it is reversible. But also, don't use it as a contraception method either because I know some people that have tried that. It it doesn't work. You can still get pregnant.