Psychiatry & Psychotherapy Podcast - Sauna & Heat Exposure's Impact on Mental & Physical Health

Episode Date: August 30, 2024

In this episode, Dr. David Puder and Liam Browning delve into the ancient practice of sauna and modern heat exposure therapies, exploring how they influence both physical and mental health. From boosting cardiovascular and cognitive health to potentially alleviating symptoms of depression and chronic diseases, this discussion reveals the science behind heat therapy's therapeutic effects. Discover how cultures worldwide have utilized heat for healing, the physiological benefits it offers, and practical insights into incorporating these practices into daily life. Join us as we uncover the evidence-based benefits and limitations of sauna use, exercise, and other heat therapies. By listening to this episode, you can earn 1.5 Psychiatry CME Credits. Link to blog. Link to YouTube video.

Welcome to the psychiatry and psychotherapy podcast. I'm your host, David Puter. This is your gateway to the intriguing world of mental health. As one listener put it, this is the podcast that your psychiatrist listens to. And we're incredibly proud of that endorsement. Whether you're a loyal, active listener who's been kind enough to reach out, maybe send an email at DM or put in a review, or you're new to this community. We have an exceptional opportunity for you, not only to learn, but to also, earn continued medical education credits with each episode. Our credits are meticulously designed to empower you in your field, demystify complex mental health topics, and transform your learning journey into a truly rewarding experience. To access this and more, just visit Psychiatrypodcast.com. We're grateful to our valued subscribers who are already reaping the benefits of these credits. Your support is instrumental in allowing us to devote time each week to curate. this podcast, sharing cutting-edge insights, featuring top professionals, and exploring the latest

research. Whether you're here to learn, earn credits, or both, we're thrilled to have you with us. Get ready to deepen your understanding of psychiatry and psychotherapy, one enlightening episode at a time. Hi, welcome to the podcast. Today, I am joined with Liam Browning. He is a fourth-year medical student who has been on a rotation with me here in beautiful winter park, Florida. We have been consuming delicious food, going to springs, enjoying the heat and an occasional cold plunge. This episode will be on sauna use, heat exposure, and mental health benefits and physical benefits. Episode two, we will go into cold plunge and kind of the cold water swimming and the benefits of that, I think that this is going to be a very interesting episode that you probably have

very little exposure to in a normal medical education. I don't remember once being told anything about sonius other than maybe in the history of psychiatry when we talked about it's being use in, or it's use in like ancient civilizations and heat and cold and back and forth. So, welcome to podcast. Thanks for having me back on. It's fun to be in person now. We are in person. We have been enjoying good food all week. Sushi, lots of sushi. Oh, yeah. Explying me.

I posted a little Instagram clip of Liam doing a cold plunge. And someone was like, I didn't know hazing was still something that happened in medical school. And I was like, if only you knew. Yeah, I really wanted to try it. How could I come up here and talk about it if I never tried it? Yeah, if only you knew how spoiled he's been the last couple weeks. Okay, so let's start with a little bit of history, and then we're going to get into some of the, we looked at pretty much every study we could possibly find.

We looked at, you know, reviews that have been done on sauna, coal plunge, we looked at the individual studies. We looked at, there's a big cohort that was in Finland on sauna use, and we looked specifically at them. and then all of the studies involved in that cohort. It's a really nice cohort. We looked at different studies on depression, psychosis, all of the above, and different heat and cold exposure. And so, and we looked at the mechanisms, and we looked at what is known and what is not fully known,

you know, sometimes in pop culture things when you hear about sonical plunge. It's like there's so much more that's extrapolated from fringe research studies. So we're going to talk about what is actually known. Hopefully stick to the science. And we have a cool handout for this. So we'll go to the podcast. Yeah.

I'm excited to be back to do this in person. Like I said, should be fun. You know, I was thinking about the, as we were kind of looking at the history of cold and heat exposure, it seems like in every culture there is group events, bathhouses, saunas, springs. We went to the springs together. 72 degrees in Florida. And it's hard to get in. Like there were so many people we dove down about 20 feet into this spring that's gushing up.

I think you were surprised at how much it was flowing up at first. There was a big current on that spring. and yeah there is packed there there's so many people and you know like going across the u.s to like Yellowstone and all these places uh with the natural springs there's a lot of people who like to congregate to it so and even in other cultures too like in Iceland i know there's the hot springs there people like go thousands of miles just to go to the springs and to relax in them yeah so there's something in you know roman culture the bathhouses were just calm commonly places of congregating, you could see how they would put big heaters under some of them to

keep some hot, keep some cold, back and forth. There's, you know, all sorts of traditions where this is happening. Any in particular that jumped out to you as we sort of look at the history? Yeah, I thought the first historical sauna was the most interesting to me. It was out of Finland, and it thought that it was around the time of 2000 to 4,000 BCE. And essentially what they did is they built these really big pits and they lined them with animal skins. And inside the pit, they would have a fire going throughout the day. And these fires would heat a bunch of rocks that they had in there. And the rocks would retain the heat from the hours that the fire was raging.

And in the evening, they'd all congregate there. They'd put out the fire, wait for the smoke to go out, and then they'd enjoy the hot rocks. And they'd put water on that. and produce steam. So these were like some congregation areas for a lot of social events. They'd cook and clean. It was sometimes a hospital

or they'd tend to the sick there. So I thought that was a pretty interesting tradition. I just this big pit with a bunch of fire and rocks and people just enjoyed it. Yeah, I think about the history of psychiatry in Egypt they used to prescribe going to different, you know, bath experiences. And I remember reading that initially

and I was like, that seems really just out there. That seems like that wouldn't work, you know, like heat and cold. But maybe there is a link, right? So we're looking at this one study, right, from Finland. Do you want to talk a little bit about just this Ku-Pio-Echemic heart disease risk factor cohort from Finland. Yeah, so this is probably the most impressive study on Sauna use so far. And, you know, we really like these Nordic countries because they have these huge cohort studies

that they have all the hospital records from. So that allows them to have these really big cohort studies, and they follow them for years. So for this particular study, they followed 2,000 middle-aged men. The average age on study entry is 53, and they group these participants. into three different groups based on how often they use the sauna. So for the most frequent sauna group, it was four to seven times per week. And then the next group was two to three times per week. And then the lowest group was once per week or less.

And I think what's interesting about sauna use in Finland is like there's so many people who use sauna that the reference group for this study was just once a week or less. They couldn't find enough people to have like zero times per week sauna because it's so common there. The majority of the people in the study used it two to three times per week. That was the biggest group. Yeah, exactly. I think it's also worth mentioning this is 80 degrees Celsius or 170 degrees Fahrenheit for an average of 14 minutes with a range of 2 to 90, but mostly 14 minutes. Yeah, and this is dry stana specifically.

In America, you often see infrared sauna at gyms and spas and stuff like that. So in Finland, they typically use the traditional dry sauna, which is just with the dry heat with the low humidity. And then sometimes they'll add steam through adding the water to the rocks. Yeah. And that's like a special tradition, you know, and someone who can put it on and then use their towel sometime or something to kind of wave the steam throughout the room is. It's kind of cool. I think it's part of the experience. You know, infrared sauna doesn't get that hot. It's more like 120, 1.30, I think.

And sometimes these saunas will get up to 220, even, you know, which is like, which is wild. Yeah. It's also worth noting that, you know, air conducts heat about 125th as much as, like, water, right? Right. So when you're in a hot tub, like that's actually conducting heat 25 times more. So that's why we don't go in hot tubs that are like 160. Exactly.

It's more like 105 to 110 somewhere in there. Right. And then when you add the humidity too, that makes it harder to sweat. So then it adds to the relative intensity of the heat that you're feeling. So 170 at 10% humidity feels harder than 170 at 0% humidity. Yeah. And it also potentially adds the benefit that we'll get into of that dry heat and sweating, the benefit of sweating. Okay.

So before we get into the data on physical health and how physical health differed between these groups, I think it's worth noting we tried to look at depression. We couldn't find it. And I've even reached out to the cohort leader. If he's listening to this, thank you for your wonderful study. please contact me, because I didn't see depression analysis in this. We saw psychosis and we'll get to that. But most of the study looks at things like risk of stroke, risk of heart attack, risk of dementia, risk of hypertension. So one thing I was thinking about before is just to emphasize how intimately connected physical and mental health is. So for example, the average 60-year-old person has depressed,

somewhere between 5 to 13% of people will have depression. So think about it like 10%. Okay, so out of 10, one person will probably be in a state of depression. Post-stroke, it jumps up to 23 to 33%. So out of 10 people, 2 to 3 people will be depressed post-stroke. Post-heart attack, about 2 out of 10, 20%. if you have out of control diabetes, two out of ten, three out of ten, 20 to 30 percent somewhere in there. And dementia, it's even higher. It goes up to 40 percent. So somewhere between 20 to

40 percent of people with dementia will have depression. So two to four out of ten. Okay, if hypertension is out of control, once again, it's like 15 to 30 percent. So around three out of 10 people without a control, hypertension will have depression. Okay, so what does that mean? That means like, remember, the average person is 5% to 13%. So it's about six to, you know, it could be six times more likely of having depression if you have one of these physical illnesses six times. Yeah, and I think that kind of speaks to how cardiovascular,

disease and chronic brain disease like dementia and stroke, that affects the function of the brain. And if there's anything that's decreasing the function of the brain, the brain's probably not, you know, the neurons aren't going to work as well. You're probably going to have some mood effects, cognitive effects. So anything that affects the heart and the brain, it's probably not great for depression or any other type of mood symptoms. Yeah. We want to preserve our physical and mental health as long as we can in our life, right? So we talk about the lifespan versus the health span, right? I would prefer when I'm 70 years old to be as sharp, you know, as I am today.

Yeah. And so, you know, when I think about loving my family well, it means like how do I best take care of my body? How do I best take care of my brain? And so we're going to talk about these things. Okay, so let's talk about the three different groups and how much the sauna users who used it three to seven times per week. What kind of reduction in illness did they have? Yeah, compared to the group that used sauna once a week, the three to seven times per week group,

they had a 40% reduced risk of all cars mortality, 50% reduced risk of fatal cardiovascular disease, 48% reduced risk of fatal coronary artery disease and a 63% reduced risk of sudden cardiac death. That's huge. Yeah, that's huge. Those are huge numbers. So think about it like 50%, if you just think about like half as much, okay, half as much will have all the different things that we don't want in general.

Okay, if you, I know we don't want to, when we talk too much about statistics, it's hard to kind of like grasp it. But the people who use, it three to seven times per week at about half the rate okay what I mean come on it must be body mass index it must be systolic blood pressure LDL smoking previous MI what about those are we adjusting for those yeah and we adjusted for all these different baseline characteristics and the different groups like you mentioned BMI blood pressure cholesterol smoking history whether they had a previous heart attack they had diabetes their physical

activity and their socioeconomic status. So like with these large cohort studies, any sort of epidemiological study where you're looking at a decreased risk based on some sort of intervention that you have. In this case, you can say that the people who use sauna more often may be more healthy than someone who doesn't use sauna. So they actually controlled for this. And then also when you're looking at these large cohort studies in any epidemiological study, You want to make sure that you look at the dose response relationship too. So in this case, the group that uses sauna two to three times per week, they didn't have a significantly reduced risk of these outcomes like all-cause mortality

and decreased cardiovascular disease. So the fact that the three to seven times per week group did suggest that there is a dose response relationship. And then even when you look at the duration of the sauna use that they did, there was only a benefit above 19 minutes. for the sauna session. So if they were in the sauna for more than 19 minutes, they had a significant effect on their cardiac death

versus 11 to 19 minutes did not confer the same benefit. This is compared to sauna's less than 11 minutes. Yeah, so there seems to be a dose response. Remember the control group in this, the group where you're comparing, you know, two is using this on a one time a week on average. So the control group is probably not the average American. Okay, so yeah, really, really interesting.

And then there were follow-up studies of this as well, where they looked at the once-weekly users compared to the four to seven times per week user. And once again, 47% lower risk of high. Hypertension, 62% lower risk of stroke, 66% decreased risk of dementia, 65% lower risk of Alzheimer's disease, 37% reduced risk of pneumonia, 78% reduced risk of psychotic disorder. And this one made us go, huh? Like what? Psychotic disorder? Like 78% reduced risk of psychotic disorder? Like what? Yeah, but that was very, very high.

And so we were like, well, what if like these people who had schizophrenia already? Because remember, the age at which they introduced people into the study was like in their 50s, right? 53? So what if these 2,000 people, what if some of them already had psychosis? And they're just not using this on it because they're isolating. Right. And they try to control for that by excluding people on antipsychotic. So this had me very curious, you know, like, okay, what?

78% reduced risk of psychosis. Like, should I be recommending sonnet all my patients with psychosis? And one of the things that they commented on in their discussion was that they didn't separate people who had psychosis due to dementia and due to like a primary psychotic disorder. Yeah. They did try to control for people with depression by excluding people in one set of analysis with, like, who had been on an SSRI. And that didn't seem to do anything.

So it's not just like depression with psychosis. But they, some of these people probably had delirium. Okay. Yeah, I definitely think so. And so we know that the high sauna users had reduced risk of MI, reduced risk of. stroke, reduce risk of dementia. So therefore, their total brain capacity was better. Did that lead to less dementia?

Did that lead to less dementia? Did that lead to less delirium? I think so. Yeah, probably. And so I think delirium is probably one of those things where it's like it reduced risk of future delirium and psychotic illness, right? No.

But we don't really know what's what, we do know that people who use this on are probably out of healthier brain. Yeah, and I think like the number here is 78% reduced risks for psychosis. I think that is probably a little bit conflated. Like you can make an argument for the reverse causality where there's people who are more psychotic, less disorganized, or more disorganized, less social. So they're not going to be as likely to actually use this on them. But that sort of argument doesn't really work for these other car.

cardiovascular outcomes. So I think those numbers are probably more realistic because like a sudden cardiac death, that's like a sudden death that's not going to keep you from using the sauna because you're already dead. So I think the fact that you're seeing a 70% reduced risk in psychosis might be a little bit conflated just because of that reverse causality. But there is probably some benefit to it. So maybe it's on the order of like 20, 30% somewhere around there. But I think that's why we need more studies on this topic because, you know, we're seeing these impressive outcomes. we want to learn more how we can actually apply it. Yeah, I think when I see a study like this, it makes me think like, okay, what's going on here? I'm curious about it. It doesn't lead me to

say this causes this or this will reduce the risk of this. But with patients who want to optimize every potential area and are, you know, willing to take some risks, right? Okay, the risk of doing some sauna may have some other benefits, reduce the risk of these other diseases. But I think what your point here is like something that I really thought about. Like, okay, most of my patients who have psychosis, who are isolating are not thinking about going to a public place where they may use a sauna.

Or they're in Finland. I think there's just one sauna for every three people. So there's a lot of like home saunas. So, but it's a very social event as well. And I think that social aspect is very meaningful and hard to tease out like how much that social aspect is actually improving things as well. Right. So I think, I think the biggest, the biggest thing that I was thinking about as I was thinking

about this was like, okay, how much is this like, you know that study about like rat heaven where you give the rats like everything? Oh, yeah. What is it called? Environmental Enrichment. Yeah. And they just like thrive, right? Yeah.

Like how much of the sonic experience, and then often they're going into a lake afterwards and they're with friends and it's back and forth. It's like it's very relaxing, right? And so how much of that is playing into this like benefit that you're seeing on multiple domains? Yeah. Yeah, I think there's probably something to it.

Not just in psychosis, but like you said, multiple domains of reducing the cardiovascular outcomes too because we know that increased sociality can lead to a longer lifespan and better cardiovascular outcomes as well. And then, of course, for depression, which we'd like to see the data on, but fortunately at this point we don't really have. For that, for this study. Yeah, for this specific study. Right.

Okay, let's think about comparing to other interventions like aerobic exercise. what did this study specifically look at aerobic exercise and how much that reduced all-cause mortality? Yeah, this specific cohort study, they had a separate study looking at the all-cause mortality of people with a high-v-O-2-max versus a low-v-O-2 max, meaning like greater than 50% V-O-2 max compared to people with less than 50% of VO2 max. And of course, for people who don't know what VOTOMX is, that's the maximum number of oxygen that you can consume. and it's a very good predictor of your cardiovascular health.

So what they found in this study is that those with the higher than average VO2 max had a 35% reduction in all-cause mortality compared to those with lower than average VO2 max. So this is within the same cohort. So that sort of comparison is actually really good to make. Yeah. And then there was another cool meta-analysis if you're thinking like, oh, I'm not in incredible shape, just walking two and a half hours a week. really is helpful compared to doing zero physical activity.

So there was one study where they looked at, you know, 11 prospective cohort studies, Garcia, at all 2023. And they found that walking two and a half to five hours per week compared to zero physical activity had about a 33% decrease in all-cause mortality, cardiovascular disease, and actually a 16% decrease in cancer mortality. So just doing some level of daily walking, getting your steps in,

like that can have a reduction. Now, this doesn't seem as profound as that sauna study, but you can't really compare one to another because of all of the variables that are hard to tease out, right, in a cohort study. Right. And then also for this study, you know, walking two and a half hours a week,

doesn't sound like that much. And I mean, and compared to how much V-O-2-Max you can improve, like, you can have these crazy endurance athletes top percentile of V-O-2 Max, and these people are probably going to have less cardiovascular disease compared to someone is just walking, right? So that's kind of where this famous VO2 Max study and mortality kind of plays in, where the study looked at a cohort of participants where they ranked them based on their VO2 max performance and they put them into five different categories. So compared to the lowest category, which is people with the VO2 max in the bottom 25th percentile, so the bottom one quarter of all people,

compared to those people being in the 25th to 50th percentile, so slightly below average, that gave them a 20 percent reduced risk of all-cause mortality. And then going up from there, being from 50th to 75th percentile, so above average, gives you a 63% reduced risk of all-cause mortality. And then even going above that, 75 to 97.5 percentile, which is considered high, that gave a 74% reduced risk. And then being elite in the top 2.5%, give you an 80% reduced risk of all-cause mortality. So even going from below average to above average of cardiovascular fitness probably does give

you a greater effect. Yeah, I think, I mean, think about that 74% reduction, just for being in the top quarter of physically fit people your age. Like, if you can just be in, like, the top 25%, you know, like, that's not running marathons. Actually, marathons, doing too many marathons may not be good, you know. Like, if the extreme, there is a level of extreme athleticism where, you know, you are competing at the highest level,

and it may not be the best for your body, you know, may cause some scarring and your heart and increased arrhythmias and stuff like that. And so there's this kind of like perfect middle zone if you're looking for just peak performance and your cognitive abilities and health abilities. And I think that 72%, 74% reduction,

it's higher than what we're seeing in just the son use, right? So if you think about like hierarchical, like beneficial things maybe this the reason why we're including this is kind of put it in perspective let's let's look at diet and how that kind of reduces risk and put that into perspective as well yeah diet i think right now the studies are kind of limited because they kind of they just look at one sort of one type of diet uh so looking at the mediterranean diet that gave a 20% reduced risk of stroke, 21% reduced risk of cardiovascular disease mortality. And then looking at omegas that gave a 15 to 18% reduced risk of all-cause mortality. And I think what I said about

limiting how diet studies are limited is that we know that caloric deficits are probably what gives the best benefit for mortality and for cardiovascular health. And I mean, it's not realistic to put someone on a prospective diet for like 20 years and have them be in a caloric deficit. So I think the main takeaway is that the less you eat, probably the longer that you live in general is what... Do we know that though?

Like, have you seen those studies? At least based on animal models. Based on animal models. It's crucial here. Yeah. Right? Okay. Because I think in general,

you can think about like a 20% reduction with Mediterranean or with high omega-3 foods. Like, yeah, we should eat those. Those are good for us. Those are good fuel for our body. But that kind of puts in perspective, like exercise, you know, being in the top 25% versus the bottom 25%. That's a 74% reduction.

Sani use, it seems to be about around of 50 for a lot of things, right? And then food is like 20. It's kind of, you can't really compare these things because they're different cohorts, different types of studies, but it gives you a general idea of how powerful that finish sauna study was. Okay. What about differences in the baseline characteristics between the two groups of sauna users? Like, is there any limitations we should talk about here?

Yeah, so again, this is kind of going back to maybe the sauna group that uses sauna more had, they're already healthier when they enter the study. And like we mentioned, they controlled for this. Like there was a high rate of smoking in the lower sauna group compared to the high sauna group. But surprisingly, the high sauna group actually used alcohol more. So, I mean, there's some nitpicky percentages here. I think they did a good job of, you know, having the comparable, like, baseline characteristics between the two groups. And they controlled for it.

So I think it doesn't really take away that much from what we see in the state. study. I think the crazy alcohol consumption, it's like 95% versus 83% of people use alcohol. So everyone's still using it. Everyone's using alcohol. And then also there's the idea of like the healthy user bias where, you know, in America at least you could imagine if someone's using the sauna four to seven times a week, that probably means they can afford to go to a spa or a really nice gym that has a sauna there. But YMCA's often have saunas too. Yeah, but I mean, it's not like Planet Fitness where they have like maybe a really crappy tanning bed, but no sauna. So like in Finland, like everyone has access to a sauna pretty much.

But yeah, and they looked at the socioeconomic status difference between these groups and there wasn't statistically significant difference between the groups. Yeah. Yeah, I think that in the U.S. it could be considered at this point. Like, yeah, higher SES may have more access to it. But I think there are a lot of like gyms. It's like, I know people who don't have a lot of money, but they figure out how to do it, like go to YMCA or go somewhere.

It's like, you know, they ask around when they plan on going to a gym, like, do they have a sauna? Do they have a cold plunge? Right, but then if you were to study this in Americans, that's like the healthy user bias. That person is willing to go out of their way to get a sauna. Maybe they're willing to go out of their way to improve their diet and they're already exercising.

So that's where it's similar to like vegetarians, where vegetarians are going to be more health conscious of their food choices, maybe their exercise choices. So studying sauna in America probably would not be as strong as studying it in Finland like this study. In a cohort design. I think this is, and we'll talk about kind of like where we could see this being studied

in a randomized control trial at some point. Okay. So any takeaways. Let's talk about big takeaways. takeaways. Yeah, one of the big things is the type of sauna that they used was the dry sauna, and they did it for 20 minutes. So 20 minutes probably confers the best benefit at 172 degrees. So this is not your average sauna. I'd say in America where the infrared, like you said, is like 120. These are pretty intense sessions, and I'm sure these are like veterans of sauna users.

They've got acclimated to the sauna. Like the average person should probably not start out of this number. they should probably work the way up if they're interested in trying this. Yeah, absolutely. First of all, always consult with your doctor before you try something. But yeah, you want to listen to your body. You know, it takes probably months to get heat acclimated. So you want to just plan on it being a process and listen to your body and not jump into it too quickly. It's like, oh, I need to do 20 minutes.

So I'm going to pass out or something. It's like, that's an awful idea. Yeah. And even if you don't have a sauna access available, there's some data out of Japan from a prospective cohort study that doing hot baths on a daily basis confer some cardiovascular benefit where there is a 23 to 40% reduced risk of adverse cardiovascular outcomes

compared to groups that did not bathe daily. So even if you don't have sauna, there's probably some benefit of taking hot baths. Yeah. I don't have a sauna at home yet. I'm thinking about building one. But, you know, the hot baths, you know, put a thermometer in there. And it's hard to stay in there for like 20 minutes.

I took one a couple weeks ago for the first time in years. When I got out, I was like, oh, man, it was crazy. And then I was reading like how much you're like you can put yourself in a fever by staying in. So it's like, be careful, guys, because you could put yourself into like a 104 fever if you stand for 20 minutes. Yeah, definitely.

Reduce your blood pressure too. You can pass out. So yeah, you got to work your way into this and obviously consult your doctor. Right. And so there may be benefits, like in the process of working your way into something, like how is your body changing?

There's epigenetic changes. You know, I'm expressing this to a patient the other day. I'm like, you know, if you were to, start exercising or start using the sauna or something like that, it's not just like one gene that's going to change, right? If we look at diet studies that I've looked at where it's like looking at the genes that change, it's like thousands of genes that are upregulated, downregulated. So it's going to take time, you know, and how long do epigenetic changes take months?

Right. So plan on it being a process if you're into it. And also this social aspect, right, is so important in my mind. Like, and I really do think a lot of the benefit is probably that social aspect, the laughing, the having fun, the doing it together. So it's like, I feel like in America we can like look at data from Finland and go like, oh, we need to do this. Like we need to grit our teeth and like, hey, we're going to hate this and we're just going to do it anyways because it's good for us. It's like, it's like these longevity studies, for example, on exercise. Turns out tennis has the longest life-increasing longevity span. Well, why is that? Maybe it's because there's a social aspect to it. Maybe it's because maybe it's more than just the exercise, right? Right. And like you think that cycling or running something very cardiovascular intensive

would give you that benefit, but it's actually tennis. And you can't play tennis by yourself last I checked. So there's probably that social aspect that leads to the benefits. Part of the benefit. Part of the benefit. Thought about that with the Adventist Health Studies and looking at how the vegetarianism increases lifespan. It's like, how are you controlling for just the community

and the group of people that are doing this together, you know, and how much of that is just the benefit of that community? Okay. Okay. So additional studies assessing cardiovascular health. Shall we go into some of this stuff? Yeah. I just wanted to mention that part of the benefit for cardiovascular health may come from the reduction in blood pressure. We know that blood pressure is a huge predictor of mortality, cardiovascular disease, stroke, and dementia. So what we found in these studies is that, like I mentioned,

the 4 to 7 per week group for that prospective study had a 47% reduced risk of being diagnosed with hypertension. And there's been several randomized controlled trials about sona use, and they find that systolic blood pressure tends to decrease by about six points in these studies. And in some studies, it's actually a little bit more. So, I mean, like comparing that to like other lifestyle interventions, that's the, Like, six points is a lot. Like, looking at the dash diet, that's, you know, emphasizing fruits, vegetables, whole grains,

low-fat dairy, and reducing sodium intake, the dash diet gives you about six to 11 points on your systolic blood pressure. And, like, that, having a sauna be comparable to one of the best evidence-based methods of reducing blood pressure. I think that's really impressive. Yeah, and it's similar to aerobic exercise. it's similar to, it's maybe a little bit better than sodium restriction, possibly because they're sweating out some sodium as well.

It's better than alcohol in moderation, which is like two to four units of blood pressure. And the weight loss is another thing that can reduce blood pressure. Just one antitensive medication usually reduces about 10 to 15. So if you combine a couple of these things, you know, like let's say you're newly diagnosed with hypertension, okay, combining a couple of these things together might be, you know, another option, right?

Yeah. However, thinking about like a 40-year-old with newly diagnosed hypertension, it's like, okay, you need to start exercising, change your diet, and start using the sauna. Or you can take this pill. And a lot of patients will be like, I will take the pill.

you know. And some of them will be like, I'll take the sauna. And some are motivated and want to do the holistic pathway, right? Okay. Yeah, and so what is the cause of the anti-hypertensive effect of sonnas, do you think? Yeah, based on a couple of studies, it seems that the anti-hypertensive effect is due to the effects on endothelium. So causing the inner lining of the blood vessels to be able to dilate better. having reduced arterial stiffness,

and then changes to the autonomic nervous system. So if you think about those three things together with the fact that sauna also increases heart rate during the sauna sessions, that can increase to 100, even to 150 in very intense sessions, you start to see... Especially in those longer sessions where you're 20 minutes in...

At a very high temperature. You're getting moderate exercise at that point. Exactly. So you're seeing all these effects and saying like, okay, it kind of looks like exercise. To some degree. Yeah, to some degree. To some degree. Because, and we'll get to this study where they looked at exercise alone versus exercise with sonius.

And it seems like the blood pressure changes was only in the exercise plus sonnet group. Yeah. Yeah. So yeah, in this study they compared eight weeks of exercise alone, which in this study, they used resistance and aerobic exercise. And then they had, they compared that to control who did nothing and then also exercise plus sauna. So the sauna was added on top of the exercise intervention that they have.

Yeah. And this is Lee at all, 2022. So this is, this is a randomized trial. Yeah. where they're randomizing them to exercise, which is actually pretty long. Like the exercise group was doing strength training and cardio, right?

Yeah. Whereas the sauna group was doing strength training cardio and then sauna. Yep. Okay. So interestingly, the exercise plus sauna group had an improved VO2 max,

more than just the exercise group, decrease in cholesterol by 19, which is pretty cool, and then a systolic blood pressure decrease of 8 millimeters of mercury. So that's pretty cool. Yeah, that's a huge effect. And I mean, my one sort of limitation to this study is that they added the sauna on top of the exercise.

So that means, like we were mentioning, if sauna is sort of similar to exercise where it increases heart rate, then maybe that additional couple of minutes did have some effect, and that led to some of the improvements. So I think that if there's other studies out there that are looking to do like a randomized control trial, you want to make sure that they're actually controlling for the number of minutes that they have the patient in the sauna

compared to exercise. And there's a couple of acute studies looking at that and looking at the acute effects on the blood pressure, and it seems like they're about the same. But maybe there is something unique to sauna that causes these unique health benefits. Yeah. And I think it makes sense to my brain

that there are unique epigenetic modifications over time that are taking place in your different cells to get you more heat adapted. And thinking about like, we were looking at the world record. and there used to be like this competition on like how long people could stay in like a sauna like thing and these are incredible temperatures right and eventually there was some deaths that led to the end of it but just the idea though that humans could over time develop the capacity for extreme ranges of

cold and heat is so interesting to me yeah I mean in that competition they started with above boiling temperature of the sauna and adding water to the rocks every 30 seconds and increasing the temperature. So it was insane that anyone could even stand in there for a minute and people were in there for I think like six minutes or longer. Until one of them died. Until they died, yeah.

Before that, there were lots of competitions for years where I don't think they had as much water on the rocks and they would just raise the temperature, like, I think they started at like 220 or something like that. Boil-y. 220 Fahrenheit. And then they would just raise it like one degree every minute and people would stand for like 20 minutes or so,

the world champion. That's crazy. That seems like so unpleasant to watch and like there's nothing in me. It's like a very sort of like, let's just get really competitive with everything that could be enjoyable, right? It's like, oh gosh.

Yeah, let's take the fun out of it. Okay. So could aerobic exercise in combination with frequent sauna have a synergistic effect on mortality? What do you think? Based on the K-IHD study or the Finnish cohort study that we're talking about, they did have one study where they looked at combined sauna and exercise and having a high cardiovascular. vascular fitness of above 50th percentile and using sauna together that had the greatest benefit for all-cause mortality where they died the least in this cohort comparing that to just exercise

alone and then also compared to like low cardiovascular fitness and high frequency sauna. Yeah, interestingly, when you look at the graphs of cerebral or, cardiovascular disease and all-cause mortality, you really see the biggest jumps when you look at fitness levels almost, where it's like, okay, so if you're not physically fit and you're using this on it frequently, there's a substantial improvement. Yeah. And when I looked at that data, I was like, oh, I have these patients who cannot exercise for various reasons.

Like, they just can't, right? And so getting in the sauna could give them that cardio that I know it's good for their mental health and good for their stress and stuff like that. There does seem to be the best

differentiation with both sauna use and exercise, and it really shows up in the last like five years of the study more. So they're about even, until like year 25 to year 30, which is interesting to me. So it's like what, you know, what is that benefit?

It's like so prolonged, you know? Yeah. I don't know. I think it definitely has some sort of preventative benefit that we don't really understand at this point. And like you mentioned, like having a high body temperature probably has some effect. And, you know, looking at exercise compared to sauna, oftentimes you're not going to see huge hyperthermic conditions like you'd see in the sauna.

Like doing, walking for two miles, you're not going to be running a fever, but that's still going to give you the cardiovascular benefit. So maybe there's something to just being hot by itself, and that could cause some sort of epigenetic benefit. Right. Because I think you're the, like, is your endothelial layer of your blood vessels, needing to adjust to basically dilate properly and cool some areas, heat other areas are, you know, the cooling from the middle of the body, right, cooling the rest of the skin, right?

Or the sweat glands working better than they would otherwise, you know, like the sprouting of new blood vessels to allow for better heat transfer. all of these things happen over time, you know, as you can see with people who are pushing the limits of this over years to be able to do crazy things. Right, but then there's, I think we come back to as well, the interaction with people, like how much of,

like, that improves mental and physical well-being. Well, we know it does, right? So, so when you design your sauna, you know, don't just get a one-person sauna, you know, get like a four-person one so you can invite some friends over to the experience. Okay, yeah, so other potential benefits. So thinking about like heart failure patients, there's a meta-analysis that suggests that it could help them.

Yeah, it could potentially help their symptoms and even reduce B&P, which is a marker for how stretched out the heart is essentially and it tracks its symptoms as well. So there's other benefits too probably for peripheral vascular disease, peripheral artery disease where like you mentioned, improving new blood vessels forming, it probably helps with that as well. For type 2 diabetes, there's not good quality evidence at this point, but I think if it is mimicking exercise, then it probably could be beneficial. but I don't think there's been any good studies on this yet. And then looking at inflammatory joint disease,

like rheumatoid arthritis, psoriotic arthritis, enclosing spondylitis, these sort of studies seem to suggest that there is a benefit for mud baths. I haven't seen any sauna studies yet. I know how you feel about mud baths. When you told me this, I thought of two things.

I thought of suits where there was this kind of weird character in suits who like was really into mud bathing mud bathing um and then i thought to myself like no we got to keep reexamining the science like this isn't something you could not admit to it can you imagine never get you in a mud bath me inviting people over for a mud bath like i have like this giant mud bath i've created you know that like heats it to the perfect temperature and stuff oh man no yeah the the mud in this these studies, they took clay and also like algae and all their plant materials. So it really was not. They were doing a good mix. Yeah, they were doing a good mix. They're doing a good mix.

Yeah. Okay. How about depression? Let's jump about, let's jump talking about depression. Yeah, depression. This is where everyone's interested. Now, there's been a limited number of randomized controlled trials. The first one was out of Japan by Masuda at all in 2005. And this is actually the only study in sauna use. There's been other studies on like hypothermia, which we'll get into. But for this study out of Japan, they had 28 patients with mild depression and somatic symptoms, and they did five sonnas per week for four weeks. And the sauna temperature was at 60 degrees Celsius, and they did it for 15 minutes. That's 140 degrees Fahrenheit. Yeah. So it's, it's, you know, it's that infrared trying to get deeper into your body, the heat.

Okay. Yeah, not the dry saunas. This is mild depression and somatic symptoms. Yep. And so the somatic complaints were significantly decreased, and mental complaints were decreased to trend level significance in the sauna group according to the Cornell Medical Index. And there were no differences in the self-rating.

depression scale, which is interesting. So one scale showed difference, mostly somatic differences, but one scale did not show a significant difference. So yeah, any other, any thoughts on this study? Yeah, I think, you know, for patients with appetite, they did show that there was an improvement in ghrelin, which is like the hunger hormone, essentially. And so that was one of the main takeaways that they had from the study. they were initially looking at growling and seeing how appetite can improve.

And there was a beneficial effect. And that might be related to the metabolic effect that sauna has. So people were less hungry or producing? They're more hungry. They're more hungry. Yeah. Okay. You know, like appetite decrease can be a symptom of depression.

So they kind of threw that in the mix. And a lot of studies have used this to support the idea that sauna is improving depression, but I don't think it's the most strongest evidence to date looking at this. I think the other piece to consider in looking at this is a short-term study four weeks. Remember in some of the Finnish studies, we're really seeing the big difference, like much as years go on. Secondly, it's 15 minutes of infrared sauna, whereas the finished study said the most benefits were happening around 20. Right. So it could be underpower. So it's kind of like hard to underpower potentially. Yeah, you're like your findings, you know.

Like if you want to find no findings, you know, make the temperature much less than would be helpful and shorter duration. And then you're also not getting that benefit of the becoming more heat adjusted over time too, right? That takes a while. Because I think at least my experience with the cold experience. exposure. It's like it's taken a while to get more cold adjusted. Yeah. So there's going to be some epigenetic changes that need to happen that are probably going to take a while too. And even probably in the brain too, if there is beneficial effects through the cardiovascular system, that's probably going to take some time for the brain to be

able to adjust to that increase oxygen and whatnot. Also I've heard from people who do like more of like the dry sauna versus the infrared. They say they have to stay in the infrared a whole lot longer to get the same sort of effect for them. Maybe they're in it for like an hour compared to 20, 30 minutes, you know. So take that in consideration. Okay. Are there, there was a review of depression studies of whole body hyperthermia? What do they find from that?

This review looked at seven different studies and they used whole body hypothermia, which in this case, they, I think it's kind of funny. they put patients either in a hot bath or in this, like, weird chamber. So this chamber is essentially... It looks comfortable. It looks like a relaxing, comforting chamber. Yeah, but if you're claustrophobic, I don't know, because they put like a cubicle on the hospital bed, and inside the cubicle, they seal it, and they put infrared heating elements, and then you're also covered in a blanket. it. So what they did in these studies is they'd heat the participant up to up to the point where they had a fever like 38.5 to 39 degrees Celsius, which is I think somewhere around 103 to 105 degrees

Fahrenheit. 39 is 102. Okay, 102. So around 102 degrees Fahrenheit. And they do this for up to 45 minutes. And then after they had this fever, then they'd turn off the heating elements and they'd keep them in the blankets. So they'd still be pretty hot inside of the seated chamber. Meanwhile, for the bath studies,

they typically had the water temperature at about 40 degrees Celsius, which is 103 Fahrenheit, or 104, somewhere around there. And they put them in that water temperature 104, yeah. For 20 minutes, usually, or 20 to 40 minutes.

So in the study, there were three, open labels, open label studies, and four randomized control trials. And all three of the open label studies did find a significant benefit on depressive symptoms. And if they did report an effect size, it was actually pretty high. It was 1.71 to 1.85 to the studies. And meanwhile, for the randomized control trials, three out of the four did find a significant effect in the hyperthermia group. But the magnitude of the benefit was inconsistent. And I want to talk about, I think, what is probably the most impressive randomized control

trial to date. This is by Janssen et al, titled Whole Body Hypertramia for the treatment of major depressive disorder, randomized control trial. And in this study, they put 34 participants. It randomized them to either the infrared chamber or sham therapy, where the controls would go to the infrared chamber and then they wouldn't turn on the heating elements. Very mild heat. Yeah, very mild.

Very mild heat. It was a single infrared session? Yeah, and this was one session. It wasn't repeated. And they were going until their rectal temperature reached 38.6 degrees Celsius, which is 101.4 degrees Fahrenheit. So they got them into a fever, and then they, have them sit there in the machine for another 60 minutes wrapped in blankets.

And that took 47 minutes to get them there. Yeah. So it's not a comfortable experience, I can imagine. Yeah. This is like depression evoking, right? I always think it's funny when people talk about like animal studies where they're heating them and then like what's happening biochemically to them because I'm like, okay, but the rat's not choosing to do that.

You know, like I would never force someone to do that. something like this. They have to like understand why it might help, give them the choice, because otherwise it kind of sounds like torture. Otherwise, yeah, it is torture. You don't know when it's going to end. You have no saying it. But if you have the mental capacity to sit through it and recognize that you're uncomfortable, but push through it, you know, so many things in life, like that ability can take you so far. And you're, you feel a lot better about yourself if you push through something uncomfortable. So there's definitely a benefit to doing it willingly. as opposed to just sitting there and having it done to you.

Right. Okay. So what happened? What are the results of this one study? They found that after one week, after the single session, that there was a large decrease in depression in the whole body hyperthermia group compared to the sham treatment. The effect size was 2.23.

And this effect size persisted another five weeks. So at week six, the effect size, with 1.66. That seems wild to me that one treatment could do that. That doesn't make sense. Yeah, to me,

it didn't make sense either, and I don't think it still makes sense because it's just one treatment. And I think part of the reason why you're seeing this huge effect is it could be related to their expectancy of the treatment working, and they measured this

before they gave them the treatment. and the whole body hypothermia group, they actually had a higher expectancy of the treatment working compared to the sham group. So that could somehow play into the outcome that they got. Okay, but 70% of the sham group did believe they received active treatment.

Yeah, which I think is also a point for, actually point towards the study that maybe there is some effect to the whole body hyperthermia. But I think the effect size of 1.6, I think it's probably a little bit conflated. Yeah, it makes you wonder. But it's like a study like this, it's like, okay, let's get some more studies, you know?

Yeah. Okay, where's the drug company to fund this? You know, there is none. So, yeah, that's the sad part, right? There are other randomized controlled trials using multiple sessions, though. Yeah, but they each have their own limitations. So there's one that looked at 36 patients. again, randomizing them to a sham control, whole body hyperthermia, or a weightless control.

And there weren't any significant differences because there were already low baseline scores of depression between the groups. And then there's another randomized control trial where the patients had fibromyalgia, and they're actually doing some inpatient physical therapy, psychotherapy for their symptoms. So they had fibromyalgia and a major depressive disorder. and they found that the hyperthermia group had improvements in pain, but they didn't have any significant differences in depression symptoms. There was a trend-level significant,

so the P-value was above 0.05 is 0.055. This was five sessions versus weightless control, but there was a lot going on in these patients. So they were already receiving physical therapy, physiotherapy, psychotherapy. So then it's hard to... It's definitely confounding it. It's confound... You know, there's a lot of treatments going on.

Okay. What about this? New Men at All, 2017, where they randomized 17 moderately depressed patients to two weeks hyperthermia baths at 40 degrees Celsius, which is 104 degrees Fahrenheit for 22 minutes,

for four weeks for sham control. What do we find there? They found that there is significantly more improvement in the hyperthermia group at week two. So again, this is a four-week study. So at week two, they saw a benefit. But at week six, so two weeks after they finished, the benefit was no longer there.

And that could be because... You need to keep doing the treatment. If the treatment works, keep going. Yeah. Which I think about like medications, like yeah, if you stop medications, it's going to stop working as well. If you stop exercise, you're not going to have benefits as much than if you're continuing to do it. So maybe they just need to continue to do it. Because it was a good effect size at week two.

Yeah, it's 0.6.2. 0.62. So general takeaways from depression studies. I think it's promising. like there's we're seeing some effects but we need way better studies more larger scale more control groups like higher more highly controlled longer duration something that's actually uh similar to the finish sona so i'd like to see some funding from from big pharma but we're joking we would like to see the head get hot as well right because in

some of these studies the head is above water it's not getting hot and since we're looking at depression like is there benefit for what's going on in the brain to get a little hot we would like to see some controls where they're doing something cardio wise maybe in a group that's like getting their heart rate into the same ranges that you would get like in a sauna so maybe it maybe like they're doing heart rate targets like at first they're just supposed to get it to 90 for like 10 minutes and then get it to like 120 for 10 minutes, something like that. It's like very light exercise in a group, and then they're doing this on in a group,

so they both have that group experience. Studies like that might be good. Yeah, I agree. I think you definitely need some element of exercise as a control group, and then another control group potentially is doing nothing. Yeah, and then you have to have the right patient, right? And so this is like, for those of you who are psychiatrists who know, psychiatrists who participate in research studies,

like pharma companies, they want that perfect patient, right? Moderate depression, no comorbidities, no personality disorder, no addiction, no medical issues. Like, those patients are actually really hard to find. Yeah, I was going to say.

Because then you can actually isolate this thing, you know, and see if this thing is like, helpful or not helpful. And then the difficulty is just like when we talked about like psychedelics, it's like if you're in the control, you usually know you're in the control.

So if you're in a sauna control group and the sauna is like, let's say, 120, you may know you're not in the sauna. Right, but if you take someone who's never had a sauna before, maybe they actually think that they're the full benefit. The other thing I was thinking about, like, though, is you really need something that's progressive where it doesn't start them at 20 minutes at 160 right away, you know?

Like, and there's got to be some level of ability to help someone progress slowly and mindfully. And then I personally would want to see some cold exposure added into the study as well because I think the back and forth is so, for me, very relaxing. I've done that for years. Okay, mechanism of action of antidepressant and health effects. What could be going on? Our friend brain-derived neurotrophic factor. Good old friend, BDNF. Which we know exercise, you know, strenuous exercise increases BDNF. Heat stress does as well. So whole body hyperthermia administered via hot baths elicits a robust increase

in BDNF. You want to mention anything more about that study? Yeah, I think just the fact that there's a lot of different hypothermia conditions where you do see it increase in BDNF, and it's on the order of probably around like 40 to 60 percent, but it does seem to be acute, so it'll last for like 15 minutes after you finish it. So I'm not sure how much increasing BDNF you need to see to have some benefit. because there haven't been any studies looking at hyperthermia causing BDF

and relating that to depressive symptoms. But I think that is pretty interesting to see that there is an increase in BDNF. Yeah. And inflammation, what happens with inflammation? Now, this is kind of similar to like exercise-induced inflammation, where exercise increases is aisle 6 and then decreases, increases anti-inflammatory isle 10. So there's probably some immune benefit of sauna,

but I don't think it's clearly been demonstrated yet. It might be the case that it causes an acute increase in these inflammation markers, and then there's not much of a change after that, but I don't think it's really clear what's going on there. Yeah, so I would say with inflammation markers, it's probably very similar to exercise. You have the pro-inflammatory IL-6, which increases, and the anti-inflammatory IL-10, which increases acutely while you're doing the thing.

Yeah. You know, and I think that it's like, is stress a bad thing, like a pro-inflammatory type of IL-6? When it's acute, it's good, you know, teaches you over time, deal with, you know, dealing with stress over time is, in a progressive way is a good thing. Right. This is the idea of like a hormetic stress, which is where you give your body a stress that it's actually bad for it. But if you control it for an acute period of time, then it's probably better because then your body learns to adapt to it over time. So exercise is an example of this.

Eating vegetables and fruits, they actually have some toxins in them, but your body actually increases antioxidants to fight them. And then also cold exposure is probably some sort of hermetic stress that we'll get into. Yeah, I think an example of not stressing out your kids enough is like permissive parenting, you know, which somehow like on Twitter people think psychiatrists and therapists are all about permissive parenting. Like we think that's a good thing. And we don't. Like, but somehow that's got conflated, you know, like attachment parenting, permissive parenting. It's like always let your kid do whatever they want in every situation. It's like, no, that's not good. Don't. let or like I had a patient just the other day who's six and eight year old we're going to bed at 11 p.m. I'm like 11 p.m. Like why? Like my kids go to bed at 7.30, you know? And like, sleep. Sleep is so important. It's like as a parent, it's your role. You know that what's beneficial for the kid. The kid doesn't understand that they need sleep. But as a parent, that's your role to be able to enforce that. They're like, well, I can't just tell my kids, you know, they don't.

listen to me and then I'm yelling and I'm like, no, no, no, that's not how you do it. You give them a nice bath and then you read to them and then you turn off the lights and, you know, for my kids, we give them a last snack. Sometimes we come in and out of their room a little bit to, you know, remind them how much we love them and then they fall asleep on their own and it's like a beautiful thing. But we have to create like a pattern, like a ritual, a sleep ritual. And that's like so important. And actually, interestingly, that bath, that hot bath might be part of the benefit. Yeah, probably. Or when I lived in Redlands, I live in Florida now, and the winters were cold. So we had a cold pool, we had a hot tub, and we'd go back and forth for like an hour,

and we'd have fun. And that was like part of our ritual. And I would do that when I was stressed out, and that was like really nice. So now it's, how do you create rituals around sleep? And how do you have some stress? Some stress is good, you know, even for kids. No, the sports probably is like a common way of getting that for kids. Yeah, definitely. Where it's like good stress.

Okay, let's talk about heat shock proteins. Now, this is something that I was really interested in. because thinking about sauna, how it's different than exercise, like I mentioned, probably not getting a fever with most forms of exercise unless you're running around a lot. So the benefit to sauna may be in these heat shock proteins. And heat shock proteins are essentially a family of proteins that make sure all the proteins in the cell are doing their job. So proteins will inevitably change shape.

as aging goes on, the protein is exposed to more wear and tear. And these heat shock proteins make sure that the other proteins stay in shape. And they do this by physically using ATP and physically changing the shape of the protein, which I think is actually crazy to think about. So with aging, again, there's these proteins that degrade, and oftentimes they can clump up. and our ability to deal with these clumped up proteins probably decreases over time as heat chock proteins become less efficient their numbers might decrease so there's different diseases like Alzheimer's different types of dementias louis body dementia Parkinson's Huntington's disease these are all associated with clumping up of proteins so if you increase the number of heat chock proteins there's the thought that maybe you can actually

decrease the proteins that are clumping up and then improve symptoms. And there's actually a couple drugs out there that they're trying in, I think, phase one, phase two clinical trials looking at the potential protective role of these Hitchhaw proteins for neuroprotection for Parkinson's disease and then also for like seizures and strokes. Yeah, it's so complicated, right? We're not talking about one protein. Okay, we're talking about a lot.

lot of proteins. And these proteins are used to, they play a critical role, right, heat shock proteins, to fold and refold damaged proteins. Right. So, you know, we produce proteins. Our DNA produces RNA. RNA goes to ribosomes. Ribosomes create a protein. This protein is 100 of amino acids that just magically folds into a functional protein. right? Sometimes those heat shock proteins are helping that folding process. Sometimes when there's damaged proteins, they're helping refold them or know that they're damaged, you know. So they're doing a lot. And so the heat shock proteins are implicated in dementia and Parkinson's disease. So yeah, there's a lot that have been studied in particular. And if we got it in the numbers,

it would be like probably overwhelming at this point in the podcast to listen to all of the different ones. Suffice to say they increase in exercise and they increase in sonni use. Yep. And one point I did want to mention too is that they probably have other functions and neurons too specifically. Looking at neurotransmitter release, the proteins are involved in that process. It's thought that heat shock proteins are also, they help recycle those proteins so that neurotransmitter release can be more efficient. So there's all these different functions of heat shock proteins that we still don't really know enough about. There's really complicated signs out there.

And I think it's just good to keep in mind that there are things that we don't understand that there could be a benefit that sauna and exercise lead to. Yeah. So, you know, we want a good amount of healthy functioning heat shock proteins. That's a good sign of health. And it seems like there are things that increase that. including sauna use and exercise. Yeah.

How much does exposure to passive heat increase heat shock proteins? It seems that it increases heat shock proteins by about 30 to 40 percent, at least in rodent models. Yeah. It's hard to study it in humans because you essentially need a biopsy. Okay. So heat shock proteins, really cool area of study. vital for preventing the effects of aging, cognitive decline, dementia, Parkinson's, all of that.

Interestingly, like, exercise is so, so potent when I think about preventing dementia. Probably the number one thing that I think about exercise. Delay of Parkinson's, one of the things I'm constantly trying to get my Parkinson's patients, who are early on Parkinson's to do is exercise, because it's really helpful. Okay, so now I'm going to try to get them to sauna as well, I guess. Yeah, what about hormone changes? What about growth hormone, testosterone?

How does sauna change that? Yeah, it seems that sauna changes hormones in the same way, or at least similarly to aerobic and strength training. So there are studies looking at the effects of sauna and growth hormone, seeing that the growth hormone increases by about two to five fold. Other studies looking at testosterone see some small increases. And then for cortisol, there's been mixed effects. It depends on the study that you look at.

Some will say the increases, some will say it decreases. But I think the bottom line is that the cortisol levels outside of the sauna session don't seem to be changed much. Yeah, I think it's similar to exercise in this capacity. So I think if you're vigorously exercising, that's going to increase growth hormone, testosterone in a similar way. So both of them increase probably two to five-fold, maybe vigorous exercise more. That's what we're talking about.

Any thoughts on that? Yeah, potentially with vigorous exercise or strength training, you can potentially see an additional increase in growth hormone, testosterone, like doing deadlifts, squats, some of those big muscle groups probably involves more. And then when you look at the potential benefit of adding sauna to exercise at the end of a session, there's been, I think, one study that I was able to look at, and there is no additional increase in growth hormone, testosterone, or cortisol with adding sauna after the exercise. So that could suggest that they're using the similar sort of pathway of increasing those hormones.

Interesting. You know, it's interesting because I don't think of like very mild, moderate cardio increasing growth hormone. Do you think it does as much as a sauna? That's a good question. I think it would probably depend on how much, how intense this session was because, you know, growth hormone is going to increase to help recovery, and you're going to need to damage tissues in order for the growth hormone to actually need to be increased. Mm-hmm.

I think it is worth noting that growth hormone has been linked to cognitive functions and mood regulation. And there was one study in clinical endocrinology that found that growth hormone therapy in deficient adults led to significant improvement in quality of life, including reduced anxiety and depression, as well as enhanced cognitive function. Yeah, let's talk about sweating. I mean, this was really interesting to me thinking about. how sweat is better at removing some heavy metals than urine is. Tell me what this genius at all 2011 study found. This study looked at the relative concentrations of different heavy metals in urine versus sweat. And looking at sauna, how much sweat does someone actually lose?

They lose probably around a pound of sweat in a pretty intensive sauna. session. So losing a pound of sweat, that's actually a decent amount that you could probably say that there is some heavy metals in. And this study saw that compared to urine, there is a 3.75 fold increased amount of aluminum in the sweat compared to the urine, 25 fold increase of cadmium compared to urine, cobalt was sevenfold, and lead was 17 folds. So you're seeing these huge increases and excretion of these heavy metals compared to urine that I don't know I think that's really impressive compared to urine you know and you think about like if you're sweating out a pound of fluid for day which seems like a lot right if you're just sitting here it's like wow no I don't

sweat at all you know like how there's there's a lot of adults that don't sweat at all right they don't exercise at all. It's like, no, we probably need to sweat to just maintain a nice homeostasis of getting rid of things that we don't want in our system, you know. There is evidence suggesting that dementia may be associated with elevated levels of certain heavy metals in the brain. For example, studies have identified higher concentrations of aluminum, mercury, and lead in individuals with Alzheimer's disease, pointing to a potential link between metal accumulation and neurodegeneration. While cohort studies from Finland have shown a correlation between frequent son-use and lower rates of dementia, it remains unclear whether this benefit is directly related to heavy metal

excretion or other factors, such as improved cardiovascular health and reduced inflammation. It is also important to note that the majority of heavy metals are excreted, through the stool with a smaller amount eliminated via urine and sweat. In cases of significantly elevated heavy metal levels, chelation therapy remains the gold standard for treatment. I think there was probably a time in our culture where we didn't think about heavy metals and how they impact us, but I think it's something that we need to be conscious of because we create so many different chemicals and plastics and all sorts of things that we'd never did before.

And it's like probably going to be decades before we fully know all of the implications of that. Yeah, it's unfortunate. And you look at cadmium. Like if you like dark chocolate, then you probably have more cadmium in your system than you probably should. So maybe if you're a big dark chocolate lover, it's probably a good idea to start sweating a lot. This is good for me then, okay? Like, I can eat my chocolate while I'm in my sauna, guilt-free. Yeah.

In a future episode, we may want to dive into the complexity of this and look at where, you know, maybe humans have too much fear, maybe where we have, maybe where we should have some concern, right? Because I think it's not an aspect that it's talked about in a way that's like, let's actually look at the science and the evidence. But suffice to say in this episode, what we will say is that sweat is better at getting rid of some metals than others.

And could that be part of the mechanism of its usefulness? Potentially. I will leave it with the potential. Okay. Let's talk about safety and precautions. First of all, you know, there have been death

death in extreme competitions. Secondly, pregnancy, there is some risk of, you know, different types of malformation with extreme heat during pregnancy. You know, they tend to recommend pregnant women to not go into a sauna or go into a hot tub. That being said, in Finland, some pregnancies used to take place in a sauna. That's interesting.

So I think it's really important to mention here because we are mental health professionals, we are doctors. You know, if you're listening to this, definitely check with your own doctor. I'm now speaking to doctors with like, okay, how do we assess if a specific patient on specific medication might lead to issues of thermoregulation? We know there are life-threatening related hyperthermia syndromes in psychiatry, which are not caused by heat exposure. these may include things like neuroleptic malignant syndrome, you know, from antipsychotics, serotonin

syndrome, malignant or lethal catatonia, which is often linked to antipsychotics and mood stabilizers, antichcholinergic toxicity syndrome when someone is on a ton of anticholinergic medications. Stimulates like cocaine, amphetamine, those can cause toxicity, things that we don't necessarily give, but could lead to hypothermia and life-threatening high temperatures. There's something called malignant hyperpyraxia, which maybe anesthesiologists have to deal with, which is from anesthetic agents like succuline or inhaled anesthetics. If a patient all of a sudden decides to get off of a dopamine agonist, let's say they have Parkinson's disease, they could have Parkinsonianism hyperpyrexia syndrome, which is a high fever from that.

And then there's thyroid toxicosis from maybe high thyroid, like thyroid storm is another word for it. And this may be exacerbated by like amyodorone. Okay, so those are things I'm not going to go into a ton. We know those exist. I'm more interested in how medication is. impact heat tolerance, have any medications had a higher association with heat exhaustion, heat stroke, dehydration? These probably take place more in elderly and people with predisposing cardiovascular conditions. You know, we looked at some case studies, some case control studies,

Bongers at all 2020, Kalish Elliott at all, 2000. 16. I'll put these notes on my website, Psychiatrypodcast.com. So there are cardiovascular drugs, specifically diuretics. You know, we know you're peeing out a lot more sodium. You're getting more dehydrated and that could cause, you know, some lightheadedness, fainting type stuff, especially if you're in a hot sauna. There's also ACE inhibitors which impair thirst. And I also thought about GLP1 inhibitors also in parathurst. Remember, drink at least a couple liters of water in the morning if you're on a GLP1.

There's propanolol, which is a beta blocker, which increases sweating, and therefore fluid replacement is essential. There's vasodililators like nitroglycerin, hydrolysis, isisorbiid dinitrite, which, lower blood pressure by relaxing blood vessels, which can dissipate body temperatures, but can lead to hypotension and syncope. So, you know, fluid replacement, you know, getting in a fluid is important, especially if you're planning on being in a hot environment. Another class of medications, the anticholinergic medications, some of you may remember from episode 102, I did a deep dive on this, Anticholinergic medications can decrease sweating. Some of these include commonly used antipsychotics like clozepine, olanzapine, quatyapine, chloroprame,

also amyptylene, oxybutin, ventropine. So consider that this will decrease sweating. Now, note, like in a hot tub, sweating doesn't necessarily help you, except on your face, cool down. But in a sauna, maybe shorter durations are going to be important for this type of medication. Anti-psychotics, you know, I listed a couple there that were highly anticholinergic, but they also can impact us in other ways. We know that D2 receptors get blocked and can cause hypothermia through neuroleptic malignant syndrome.

But it could also potentially, through a non-MS mechanism affecting the hypothalamus, kind of mess with the body's principal heat regulator. So we have to consider also with other antipsychotics that they block, Alpha-1, especially those that have strong sedative properties like clopermazine and olanzapine. This reduces peripheral vasodilation. Okay. So alpha-1 usually dilates the external blood vessels. So if you block it, it constricts it. There's also clozapine, which has,

there's also clozapine which fever is actually a notable side effect in the first couple weeks of initiating the drug it prevalence is suggested between like six and sixty percent and it's hypothesized to be a result from immunomodulatory effects on the hypothalamus if a patient on Clozapine presents with fever, other things need to be ruled out like a granulocytosis, myocarditis. We also know Clozapine is highly anticholinergic and can reduce sweating in some patients. So, you know, if they have reduced sweating, constipation, urinary retention, those are anticholundric side effects. They may have also reduced sweating. However, we know Clozapine also has a paradoxical agonism at some musculinic receptors in the body leading to excessive drooling and in up to 6% of cases

excessive sweating. So that may lead to dehydration. So you have to kind of know the patient. The other thing to consider is SSRIs. So SSRIs, SNRIs can impair thermal regulation of hypothalamus and increase the risk of hyponitremia in SIDH, especially in the elderly taking fluoxetite. and satalopram. I would note that probably most people with an SSRI are probably fine, but you have to consider each individual patient. And maybe if you're considering this and you're a professional, you want them to take some data and bring it back to you like, okay,

what was it like after five minutes? What was it like, you know, what was your temperature? You know, stuff like that could potentially allow you to, to safely get someone heat adapted. Contraindications, alcohol use, hypotension, if you're really lightheaded, get out, recent myocardial infarction, unstable, angina pectoris, severe aortic stenosis, right?

Like, if you have a severe medical issue, you should probably consult with a doctor and get them to sign off on it. In no way does this episode replace your doctor-patient relationship. This is medical information for your benefit. Okay. Yeah, anything else you wanted to jump in and add,

final conclusions about SANA? No. I think we definitely just need more studies to look at how it's helping the body because we're seeing these impressive findings with the finished cohort study. We're seeing some initial results with the endopressant effect. I just think we need more funding for these larger scale studies. Yeah. And I think the other thing that we didn't really talk about,

but I have found personally beneficial, is like this as part of the bedtime routine. Like there's something about getting hot and then having maybe like a half an hour, hour, and then going to bed. There's something about that that just works really well for me, just improving sleep quality. Yeah, definitely.

It's relaxing. And I think, like you mentioned about having a routine, having a routine that your body knows and it is accustomed to you like that being in a hot sauna or a hot shower gives it a very profound signal that like okay this is going to be associated with bedtime and if you start to incorporate practices like that then it's probably going to lead to improvements in sleep. Cool. All right. So this will be the end of part one. You know, one of the things that I really wanted to know more about was when I read about kind of the lifestyle around sauna. I read a lot about

jumping into the lake or like rolling around in the snow, jumping into the ice cold water, kind of in between sauna events, right? And so one of my questions, as I'm reading this Finnish sauna study, is like, okay, how much did cold play a factor in actually the benefit, right? And so in our next episode on this, me and Liam, we'll be going through cold exposure and the benefits of that for depression, for mood. so we will end here for today thank you for listening in if you have thoughts on this episode if you think i missed a study i would love to hear from you we'll be putting all of our notes on our podcast website psychiatrypodcast.com you can get to see me for this episode uh and i hope you have a great day