How Sauna Frequency Relates to Dementia Risk
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In this clip from Dr. Rhonda Patrick's appearance on Modern Wisdom, she explains how sauna use can extend the cardiovascular stress of exercise and create a separate heat-adaptation signal. She discusses practical options ranging from a traditional sauna to a hot bath, with enough heat and time to raise core temperature while still allowing a safe, tolerable session.
Long-term Finnish cohort data connect frequent sauna use with healthy brain aging. Among 2,315 middle-aged men, four to seven sauna sessions per week were associated with 66% lower dementia incidence and 65% lower Alzheimer's disease incidence than one session per week. A later cohort of 13,994 men and women also found lower dementia incidence among more frequent sauna users. [1] [2]
Dr. Patrick connects these findings with vascular function, sleep, and preserving physical capacity when normal training is limited. The most practical routine is one that fits the available heat source, supports hydration and cooling afterward, and can be repeated consistently. People who are pregnant, prone to fainting, or managing cardiovascular disease can discuss heat exposure with a clinician before starting an intensive protocol.
Her evidence-based reference point is about 20 minutes near 174–175°F, at least four times per week; in a Finnish cohort, sessions lasting more than 19 minutes were associated with lower sudden-cardiac-death risk than sessions shorter than 11 minutes. [3] Four to seven weekly sessions produced the strongest dementia cohort pattern. This is not a universal prescription. During the first 20 years of the broader Finnish cohort, sauna temperatures of 100°C (212°F) or higher were associated with higher dementia risk than temperatures below 80°C. [2]
Timing can serve different goals. Sauna immediately after training can extend the heat and cardiovascular stimulus, while finishing heat exposure about two hours before bed may support the subsequent cooling signal and sleep. When a sauna is unavailable, Dr. Patrick describes a hot bath near 104°F for about 20 minutes with the shoulders submerged as an accessible alternative; this is her practical guidance rather than a claim that a bath reproduces the cohort outcomes.
This clip is excerpted, with permission, from Dr. Rhonda Patrick's appearance on Modern Wisdom. Thank you to Modern Wisdom for allowing us to share it.
Chris Williamson: When we're talking about cold and heat exposure, which is something that you've spent an awful lot of time thinking about, what's the best way to utilize cold and heat routine throughout a week? Like, what's just the simplest way to do an evidence-based cold and heat protocol?
Dr. Rhonda Patrick: I think one of the best ways would be if— so most people should be training, right? They should be doing some sort of resistance training or endurance training, vigorous exercise, doing the heat after that, I think, would be one of the best because you're extending your workout to some degree.
Dr. Rhonda Patrick: So, there have been intervention studies on the endurance side that have taken people who exercised on a stationary bike, or did the same exercise on the stationary bike and then did 15 minutes in a hot sauna right after that.
Chris Williamson: With basically no break.
Dr. Rhonda Patrick: With no break, they just go into the sauna after. Then VO2 max was measured. So VO2 max is like your best way to measure cardiorespiratory fitness, right? So, the maximum amount of oxygen you're taking in during maximal exercise. Their VO2 max was better in people who did that exercise, the stationary bike plus the sauna, versus just the stationary bike, right? And that is a lot because sauna, to some degree, is mimicking moderate-intensity cardiovascular exercise.
Dr. Rhonda Patrick: You know, it's doing a lot of the same things, a lot of the same physiological responses are happening. So, I would say doing the sauna right after the workout. But also, there's a new study that came out showing people who did resistance training and then got into a sauna had better muscle gains. And it just makes your workout more of whatever you did. It makes your— you know, but I think some of that has to do with the heat shock proteins too. And also, yeah, there have been studies showing that if you increase blood flow, like if you do resistance training, it used to be like this thing where it's like, oh, don't do any endurance training on the same day that you're doing resistance training, 'cause you're gonna blunt your gains or something.
Dr. Rhonda Patrick: I don't remember what it exactly was called, but that's kind of been put to rest. It's not true. So, well, I guess there's always extreme, there's always outlier, I should say, ways you could do it. But generally speaking, like, getting some blood flow to your muscles after you've done training actually improves hypertrophy, right? 'Cause you're getting some growth factors and things there, and immune cells, things that are, like, playing a role in the hypertrophy, right?
Chris Williamson: Is there a window post-training that you need to get into the heat within?
Dr. Rhonda Patrick: Not necessarily, no.
Chris Williamson: Within the same day?
Dr. Rhonda Patrick: No, I think you should do it if you— okay, you asked me about the optimal protocol. I would say optimally, it would be after training. It doesn't have to be, because also heat plays a role in sleep.
Dr. Rhonda Patrick: So, some people choose to do their heat at night, like a couple hours before they're going to go to bed.
Chris Williamson: You can go— I actually have been kind of obsessive about this.
Dr. Rhonda Patrick: Yeah. And I do both. So, I get in the sauna after I work out, and then I do the jacuzzi at night with my husband, which is another form of heat stress. You're in 104-degree Fahrenheit water. You can be in there for 20 minutes and get similar responses in terms of biomarkers as a sauna. So, I do think if you're only going to do one, you can kind of choose, like, do you have a hard time sleeping? Do you want to— or do you want to kind of extend your workout? And now, I don't know that you have to do it. Like, I think there's also been observational data.
Dr. Rhonda Patrick: By the way, the study with the cyclists and the sauna, that was in untrained people. So, you might go, oh, what about trained people?
Chris Williamson: Big gains.
Dr. Rhonda Patrick: Yeah. But then, there's observational data showing that people who exercise and sauna, so this is all sorts of people, these are people who are exercising, these aren't newbies, right? The people who exercise and sauna have a higher VO2 max compared to people who only exercise. So, there's evidence, I think, that kind of makes it a little stronger, that it's not just a newbie gain, right? Yeah. Like, that there's probably something going on. And I think it's because it's mimicking cardiovascular exercise. So, do you have to do it after a workout? No, you don't have to.
Dr. Rhonda Patrick: But, I do think it's— I personally like to do it after a workout. It's like I've already got my heart rate up. It's so it's really just like extending, extending my workout to something else.
Chris Williamson: So the 2 windows that seem to be at least interesting to use would be 2 hours-ish finishing, 2 hours before bed.
Dr. Rhonda Patrick: I say that, yeah, because some people take longer to cool down.
Chris Williamson: Yeah, I mean, I do.
Dr. Rhonda Patrick: Exactly. So yeah, 2 hours, like, to get out before, you know, because then you don't want to be trying to go to sleep and have the opposite effect, right? You're too hot, you can't fall asleep. And then post-workout. So post-workout and a couple of hours before sleep.
Chris Williamson: What temperature, how long per week, what else?
Dr. Rhonda Patrick: Yeah, so temperature, duration, frequency, like how many times.
Dr. Rhonda Patrick: So there's all sorts of studies coming out of Finland where saunas are ubiquitous and everyone's using one, looking at sauna use and all-cause mortality, cardiovascular-related mortality, dementia, Alzheimer's disease, all those things, right? And what's clear is that there is a dose-dependent effect with frequency and duration in the sauna. So, in other words, the more frequent the sauna use, the more robust the effect. So, I'll give you an example. All-cause mortality is 40% lower in people who use the sauna 4 to 7 times a week. So, 4 times would be minimum, right? Versus people who use it 2 to 3 times a week, they have a 24% lower all-cause mortality, right? So, the bare minimum would be 2 if you want something. This is compared to people who use it 1 time a week.
Dr. Rhonda Patrick: But, if you want the most robust effects, the bare minimum would be 4 up to 7, right, every day. So, that would be frequency. Now, temperature and duration, most of those studies in Finland, the average temperature in the publications is about 174, 175 degrees Fahrenheit. And, the duration in that sauna is also important. So, if people only stayed in for 11 minutes, they weren't getting a very robust effect. They had to stay in for at least 20 minutes. So, 20 minutes at 174°F, 4 times a week, is the recipe for, I would say, the best effects for cardiovascular, brain, all-cause mortality.
Chris Williamson: What about if you increase temperature and reduce duration?
Dr. Rhonda Patrick: Yeah, so this question, usually I get at the opposite because people are interested in infrared saunas, and infrared saunas go only to like 145°F. They kind of heat you up a little differently. The ambient air is not as hot. It's like, you know, electrons that are like moving your molecules in your body up. But, and so, in that case, you would want to stay in a much longer duration, and that's what's used in like Ashley Mason's study. But, the opposite, so like, if you're going to, you know, what, 180, or how hot are we talking?
Chris Williamson: Mine was 230 today.
Dr. Rhonda Patrick: Okay, so heat is a stressor. It's a stress on the body, right? And you have this stress response to the heat, right? So, your body makes heat shock proteins, for example.
Chris Williamson: You get dark thoughts.
Dr. Rhonda Patrick: You get dark thoughts, yeah, exactly.
Dr. Rhonda Patrick: And then, you get out and you feel great, but you also get chatty in there. So, it's important to keep in mind that you don't want to go too extreme on heat because it is a stress. Like, just like you don't want to, like, exercise all day, you need recovery, right? You don't want to fast forever, you need food. These things are stressors on the body, and our body has a stress response to them. So, this is kind of like hormesis. We've talked about hormesis a lot, right? Heat is the same thing. Heat can permeabilize the blood-brain barrier when you start to go to extreme temperatures.
Chris Williamson: So, you're not melting my brain?
Dr. Rhonda Patrick: I'm concerned that that 230 is too high. Yeah. No. So, there was one study that came, that was published, was it 2022?
Dr. Rhonda Patrick: It was kind of recent-ish, and it wasn't from Dr. Jari Laukkanen's group, who is the main researcher who does a lot of studies out of Finland looking at, you know, sauna use and dementia, for example. He found sauna use is associated with like a 66% reduction in Alzheimer's disease and dementia if they're using it 4 to 7 times a week. Well, another study came out, and this was in, gosh, it was quite a few. I don't remember if it was 2,000 or 5,000 adults. It was a lot, or maybe it was more actually. Well, anyways, they looked at temperature, and they looked at duration, and they looked at Alzheimer's disease risk. And, you know, it was clear that, you know, if you use the sauna, you had a lower degree, a lower risk of dementia and Alzheimer's disease.
Dr. Rhonda Patrick: But there was a subset of group where people were using it at 200 degrees Fahrenheit or more. That had the opposite effect.
Chris Williamson: Wow.
Dr. Rhonda Patrick: So U-shaped curve to temperature. I think so. I don't talk about, I don't want people to get freaked out because it's like, but not everyone's doing 200. I think there's the extreme, there's always this extreme push where I'm going to go hard. And if you're that personality type, you're going to be that person that goes all the way because that's what you do on everything you do.
Chris Williamson: Turn the dial up.
Dr. Rhonda Patrick: Yeah. Yeah. So I do think with sauna, though, it's important to keep in mind that it is a pretty strong stress on the body, particularly if you're not getting your head out, right? But if you're getting your head in there and warming it up to 230 degrees, yeah.
Chris Williamson: This plunge thing is really, really intense. I mean, there's a couple of things when you think about like, where's the thermometer actually located? Is it— Right, the highest point. It's at the top. Unless you're stood on your tiptoes on the bench, you're not actually gonna get your head to that point. And the difference between this one that I've got is 2 benches, and the lower bench is— Way cooler. Half as hard as sitting on the upper bench. And the upper bench isn't all the way at the top. And if you're at the other side to where the rock heater thing is, if you're over there, then it's easier. And if you're at the front, then it's a bit harder. So you can kind of mitigate within that, I suppose.
Chris Williamson: One consideration, like 4 times a week can be quite intrusive for somebody to get that heat exposure, especially if they don't— even if you do have a sauna at home, it's still pretty intrusive. Like, I gotta go back and forth to the thing and preheat it and all the rest of the stuff. Is there a— or if you were to do 20 minutes in at 180, 190, something like that, to make sure that it's 174, and then take a little break and then go back in. Is that a way that you could maybe get away with doing 3 times a week or 2 times a week and still try and capture some of those really good gains?
Dr. Rhonda Patrick: I don't know that that data is there to make that statement, but I do know that there have been studies looking at going repeatedly and taking a few minutes break and going back into the sauna.
Dr. Rhonda Patrick: And what is clear is that you do get big, major boost in growth hormone.
Chris Williamson: Is this the thing that 16x increased?
Dr. Rhonda Patrick: Yes.
Chris Williamson: Tell us that.
Dr. Rhonda Patrick: Yeah, so what they were doing is they were going, so they're going, I don't remember how many times, but it was quite—
Chris Williamson: 4 times 30 minutes with a break.
Dr. Rhonda Patrick: Yeah, with break, something like that. Yeah, so it's been years since I've talked about that study, but yeah, so, and that could give 16-fold increase in growth hormone, which, you know, it's transient, it doesn't like last forever, but, you know, also growth hormone's involved with and in deep sleep. And so, it's another reason why doing that, like timing your sauna around bedtime could be highly beneficial for a lot of people. Like, a lot of people really do benefit.
Dr. Rhonda Patrick: So, I personally, like I said, I kind of do both. I do the hot tub, which is 104 degrees, and I'm in there for like 30 minutes.
Chris Williamson: But the difference being that it's 104 degrees of liquid touching your skin.
Dr. Rhonda Patrick: Exactly, no. And there's been studies that have looked at, so there's heat shock proteins that are activated in the sauna, and they're also activated in the hot tub, and brain-derived neurotrophic factor, which is from exercise, also is activated when you get in a hot tub, and the sauna. So, it's like, when you start to see the biomarkers that are similar between the different heat modalities, you kind of go, well, at the end of the day, is your heart rate going up in the hot tub? Yes. It's like, I've done the sauna for years, and years, and years, and years. I know how I feel.
Dr. Rhonda Patrick: I feel the exact same way in the sauna. I like the sauna better because I'm less likely to cheat. Like, I will cheat in a hot tub. I will get my arms out. Yeah. Like, you have to have your shoulders down for 20 minutes. So you have to really like—
Chris Williamson: Didn't you, I saw you on Twitter get into a, you got in trouble with big steam, like the steam room versus sauna versus jacuzzi thing. I think there's a lot of people that are like evangelists for the sauna being the only way to get hot. And I think that you'd mentioned there's quite a lot of different ways that you can get hot.
Dr. Rhonda Patrick: There's a lot of different ways you can get hot. And I think, I mean, I've done a lot of steam showers.
Dr. Rhonda Patrick: Again, you're getting your heart rate up, you're increasing your cardiac output, you're getting blood flow increases, you're sweating. Like, all these things are happening. It's the heat shock response. You're, you know, there's a lot of ways. What is it? A lot of roads to Rome, right? I mean, it's not—
Chris Williamson: If somebody doesn't have easy access to a sauna or doesn't have one in their house, what about just running a hot bath? I mean, how much is a thermometer that you put in the bath? It'd probably be $5, maybe $10 or something. Throw that in, get it at what temperature, and stay in for 20 minutes?
Dr. Rhonda Patrick: Exactly. I do this a lot when I'm traveling, by the way. Like, I get— I do the—
Chris Williamson: The portable sauna.
Dr. Rhonda Patrick: I do, I do it.
Dr. Rhonda Patrick: But so what I, what I like to recommend is like, so go and get one of those pool thermometers, right? I mean, they're like you said, they're like anywhere between $5 to $15.
Chris Williamson: The little floaty ones?
Dr. Rhonda Patrick: The little floaty ones. You put that in your bathtub and you get it up to 104, set your timer for 20 minutes, make sure your shoulders are down, like submerged below. And if the temperature starts to go down, just add some more hot water. And, that's it. Most people have a bathtub. And so, I like that it can be accessible because that's another thing I get a lot of, oh, well, I don't have a sauna.
Chris Williamson: Privileged position.
Dr. Rhonda Patrick: Yeah. And, yeah, there's a lot of gyms, but this isn't Finland. Everyone has a sauna.
Dr. Rhonda Patrick: So, I do realize that there's a limitation on the saunas, and you might go, well, then why do I need to— do I need it? Like I said, so there's the VO2 max that you're getting even better than just exercise.
Chris Williamson: Mm-hmm.
Dr. Rhonda Patrick: Now, there are people out there who are endurance athletes. Like, they're, I don't know, do they need it for VO2 max? Probably not. But it also helps with disuse atrophy, muscle atrophy, and those studies have been done. So, they've done studies where they immobilize a limb in people for a period of weeks, and they did local heating in one study, but there have been a lot of animal studies doing sort of whole-body heating, and it'll prevent disuse atrophy by, like, 40%.
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