#048 Sauna Use as an Exercise Mimetic for Heart and Healthspan

Sauna as an exercise mimetic: the emerging research on cardiovascular and brain benefits

Rhonda Patrick's deep dive into sauna research covering cardiovascular health, longevity, and brain benefits.

"That's why I really don't mince words to this room full of cardiologists that were listening to this presentation when I said to them that I think in the next 10 years, sauna bathing may very well become part of the standard of care for the prevention and treatment of heart disease and a variety of heart conditions and for overall longevity."

Sauna mechanisms: heat shock proteins, growth hormone, BDNF, and endorphin pathways

Sauna activates heat shock proteins (prevents protein aggregation), boosts growth hormone 200-300%, and releases mood-boosting endorphins.

"So that's kind of the agenda today. All right. So over the past few decades, there's been emerging research, very compelling research, observational studies, prospective studies, interventional trials, as well as mechanistic studies that suggest that sauna bathing improves overall health. And we're going to talk about, at least sample, a few of all those types of studies today. So probably some of the largest prospective studies have come out of eastern Finland, and they're using a cohort of people that is part of a study called the Kupio Ischemic Heart Disease Risk Factor Study. And that study is is a very long ongoing perspective study that started back in the 80s it includes a few thousand individuals men and women and people are followed for you know 20 years or so and looked at a variety of different diseases are looked at so a study was published a few years years ago in the journal of American Medicine, JAMA, Internal Medicine, sorry. And what that study looked at was, in this specific case, it was men, about 2,300 men that had, you know, at least one risk factor for cardiovascular disease. And it looked at sauna bathing and its overall effect on longevity, as well as a variety of different cardiovascular-related diseases. And what it found is that sudden cardiac death, so looking at sudden cardiac death, men that use the sauna two to three times a week had 22% lower sudden cardiac death compared to men that use the sauna one time a week. Men that use the sauna four to seven times a week had a 63% lower sudden cardiac death compared to men that use the sauna one time a week. So there was a dose-dependent effect in terms of frequency. And also there was a dose-dependent effect on duration, time spent in the sauna. So spending at least 11 minutes in the sauna, there was about a 7% lower risk of sudden cardiac death. And spending at least greater than 19 minutes, so 20 minutes in the sauna, there was about a 7% lower risk of sudden cardiac death, and spending at least greater than 19 minutes, so 20 minutes in the sauna, there was about a 50% reduction in sudden cardiac death. So the duration was also very important. And of course, the data was adjusted for a variety of potential confounding factors, cholesterol, triglycerides, hypertension, socioeconomic status, physical activity, things like that. In addition to sudden cardiac death, coronary heart-related death and also cardiovascular, so fatal cardiovascular mortality was also looked at. And again, dose-dependent effect. So men that use the sauna two to three times a week had like a 23% lower coronary heart disease-related. And if they use the sauna 47 times a week, jumped up to like 43% lower mortality risk compared to men that use the sauna one time a week. And we see a very similar trend for cardiovascular related mortality. 27% lower for men that use the sauna two to three times a week and 50% lower for men that use the sauna 47 times a week. So again, nice dose-dependent effect. Sauna bathing also affects stroke risk. This also is using the Cupio. I'll refer to it as the Cupio study for short. This study was published in the Journal of Neurology, and it also found that the sauna positively affected stroke risk, and this was a variety of different types of stroke. So using the sauna two to three times a week, there was about a 14% lower stroke risk. Using the sauna 47 times a week, there was about a 60% lower stroke risk in both men and women compared to men and women that only use the sauna one time a week. Hypertension is also affected. So hypertension is probably one of those things that has really repeatedly and consistently been shown to be affected by sauna use. And again, there was a dose-dependent effect where using the sauna four to seven times a week had the most robust effect. We're talking about a 50% reduction in risk of hypertension. And in fact, just a single exposure to a 30-minute finish sauna is able to lower blood pressure in about, there was about 100 people or so in this study that had at least one cardiovascular risk factor. And after doing the 30-minute sauna session, blood pressure was lowered, and also arterial compliance was improved, so the ability of the blood vessels to expand and contract in response to changing pressure. So that's also been shown. In fact, more than one study has shown this. So most of the studies that I've mentioned up until this point have been using what's called a Finnish sauna, which is basically a dry sauna, but not dry. It uses hot water that's thrown on rocks and increases humidity. So these saunas are typically around 174 degrees Fahrenheit. You throw some hot water or water on rocks, which becomes hot, and it creates steam. And so you have up to about a 20% humidity in the sauna, which makes it feel even hotter. Most of the, as I mentioned earlier, the time spent, the duration spent in the sauna was greater than 19 minutes. So spending at least 20 minutes in that hot sauna was key for the robust effects that I just discussed. In terms of frequency, again, the more frequent, the more robust the effect. So two to three times a week had a significant effect on a variety of different cardiovascular-related diseases and conditions. And four to seven times a week was an even stronger effect. But finished sauna is not the only type of sauna that is shown to improve heart health. And it's also not the only type that's been shown to be used to manage heart disease. So another type of sauna called weigh-on therapy uses far infrared rays. And those saunas are typically not quite as hot. So they're around 140 degrees Fahrenheit. Because they're not quite as hot, in most studies what you'll see is that the duration is longer, so the duration is about 45 minutes as opposed to 20 minutes, and the frequency is higher. It's daily, every day, and most studies do between two to three weeks of this treatment daily. The major difference between a dry sauna, a wet sauna, which is a finished sauna, and far infrared ray saunas is that the dry saunas and the wet saunas, they heat the ambient air, and the heat is transferred from the ambient air to your body, whereas the far infrared rays use thermal radiation to heat the body directly, and that's the major difference. So I'm just briefly going to mention two studies that have been, that are randomized trials that have been published for the management of, one was for people with chronic heart failure, and the other one is for people that had, I think it was coronary artery related ischemia. And they're both treated with weigh-on therapy. And so using the far infrared ray sauna for about two to three weeks, patients that had chronic heart failure had improved endurance. They had improved heart size and improved disease status compared to the control group, which received standard of care treatment. And there was no improvement in disease status. For the ischemic heart disease study, weigh-on therapy was also used for three weeks, and those patients, it was also a randomized control trial, and those patients had improved vascular endothelial function, whereas the patients that received standard of care did not. And there are actually many other published studies using this weigh-on therapy, what's called weigh-on therapy, again, far infrared rays, that's used for the management of heart disease. So what you may be asking yourself, and if you're not, you should be asking yourself, is why does sauna or why does heat stress have all these beneficial effects on the cardiovascular system? And what should be kind of intuitive is that basically anyone that's under, you know, that has been physically active, you know that you elevate your core body temperature. You're getting hot. And so there's a lot of overlap between the physiological responses that occur when you sit in a sauna and when you're physically active. So typically what happens is, first of all, your skin temperature increases and your body then shifts blood flow. So blood flow goes from the organs to the skin. About 50 to 70 percent of blood gets redistributed to your skin and that's to help facilitate sweating. And so you sweat. And your heart rate increases. Your heart rate increases up to 150 beats per minute, which is equivalent to moderate physical activity. Stroke volume remains the same, but cardiac output increases to between 60 and 70 percent. So a lot of these things, in fact, all of of these things happen when you're physically active and that's exactly what's been shown a study published in the complementary therapies of medicine last june compared a 25 minute sauna session to a 25 minute session on a stationary bike doing about 100 watts and what the study showed is that in terms of the effects on heart rate and blood pressure, they were identical. So during the physical activity, during the sauna session, heart rate increased, blood pressure increased. Immediately after the sauna or the physical activity, heart rate was lower, in fact, lower than baseline, and blood pressure was lower than baseline levels. So the complete same effect happened from 25 minutes of the sauna versus 25 minutes of moderate physical activity. The sauna also has very similar effects on the autonomic nervous system as physical activity has. So the sauna has been shown to improve heart rate variability. So a 30-minute finished sauna session, just one 30-minute sauna session, it lowered heart rate after the sauna. It increased heart rate variability. It increased parasympathetic activity. So increased heart rate variability, it's basically indicative of a better capacity of the heart to respond favorably under stressful conditions. So it's a good thing to have an increased heart rate variability. And other studies using weigh-on therapy have shown something similar. And I should mention that the people that were involved in this study had at least one cardiovascular risk factor. And same with the studies using weigh-on therapy. So it's been repeated using different types of heat stress, but heat stress nonetheless. It's no surprise, it should be no surprise, that long-term sauna use has actually been shown to improve blood pressure. It's been shown to improve left ventricular function. It's been shown to improve vascular compliance and also endothelial function. All these things have been shown to be improved by physical activity as well. So cardiovascular disease is the number one killer in the United States and in fact in many other countries. But there's also other diseases that people are dying of, and there's particularly diseases that people become more susceptible to as they age, the so-called age-related diseases, like Alzheimer's disease, for example, even cancer, for the most part. So back to the CUPIO study that I first sort of talked about, which was the one that looked at sudden cardiac death and other cardiovascular-related mortalities. That study also looked at all-cause mortality, so people that were dying of cancer, they were dying of respiratory tract infections and other things. and that study also found that men that use the sauna two to three times a week had a 27% lower risk of all-cause mortality and a 40% lower risk of all-cause mortality and a 40% lower risk of all-cause mortality if they use the sauna 47 times a week compared to men that use the sauna just once a week. And we know also Alzheimer's disease has been shown to be associated with a lower risk of Alzheimer's disease associated with sauna use, which, you know, obviously vascular health is very important for your heart, and that's important for your brain as well. There's also potentially other mechanisms, which I'll talk about in a minute, but men that use the sauna two to three times a week had a 20% lower risk of Alzheimer's disease and something similar for dementia, and a 60% lower risk of Alzheimer's disease if they use the sauna 47 times a week, compared to men that use the sauna once a week. Alzheimer's disease is an age-related disease, and I do want to circle back to that in a minute because it involves protein aggregation. And one of the mechanisms, I think, that the sauna, that heat stress in general increases may be involved in preventing aggregation. And one of the mechanisms, I think, that the sauna, you know, that heat stress in general increases may be involved in preventing aggregation of proteins. But I just also want to mention, since we're talking about longevity, that in lower organisms, actually in C. elegans, which are a type of nematode worm, and in Drosophila, which are a fruit fly, just a single brief heat exposure in these organisms increases their lifespan by up to 15%. Just one sort of heat exposure, like a little sort of worm and fly sauna where they're put in a little chamber and the temperature's increased. And the mechanisms have all been worked out in terms of what's responsible for the lifespan extension. And it happens to be dependent on a family of proteins that are actually chaperone proteins called heat shock proteins. And heat shock proteins are evolutionarily conserved. They're found in worms, in flies, in mice, in monkeys, and in humans. So heat shock proteins, they respond to stressful conditions. And heat is one of the probably most robust ways to increase their expression and their activity. Heat shock proteins do a lot of things, but one of the things that they're most important for is for maintaining the proper three-dimensional structure of proteins inside of your cells. And that's really important for the function of whether that is you know to make a red blood cell or a synapse or to have you know your white blood cells functioning properly function of proteins is very important well the other thing that it does is that the the three-dimensional structure is important for the the life cycle of the protein the half-life so new proteins they perform their function, and then they get degraded, and they're replaced by a new protein. Well, sometimes just the normal aging process, so byproducts of our normal metabolism, what we had for lunch, reactive oxygen species are created, and this can damage three-dimensional structure of proteins, and it happens all the time, normal immune function. And of course, this gets worse as we age, and so those problems get even worse. But the chaperone proteins, basically, they help prevent that from happening. When the three-dimensional structure gets messed up, proteins then aren't degraded when they're supposed to. They sit around a lot longer than they are supposed to. And what ends up happening is they can then start to aggregate with other proteins and form protein aggregates. Sometimes they're soluble, sometimes they're insoluble. They can form plaques. For example, protein aggregates have been shown to play a causal role in many different neurodegenerative diseases. For example, amyloid beta protein in Alzheimer's disease, or alpha-synuclein protein in Parkinson's disease, Huntington protein in Huntington's disease. Protein aggregates have also been implicated in some cardiovascular-related diseases, atherosclerosis, cardiomyopathy, as well as heart failure. So protein aggregation is definitely not a good thing, and it does happen as the aging process occurs, it happens more and more. And heat shock proteins play a pivotal role in preventing that from happening, and also that they've been shown to actually even help negate some of the process that if it's already occurred. In addition, heat shock proteins have been shown to slow muscular atrophy. So a very recent study published earlier this year showed that people that had one of their legs immobilized for a couple of weeks that were exposed to heat and had increased levels of heat shock proteins in their muscle biopsies, they were 37% less likely to have muscle atrophy compared to the sham-controlled group. So it has been shown to prevent muscle atrophy in tons and tons of animal studies. This has been worked out in mechanisms that's been shown to be dependent on heat shock proteins. Well, heat shock proteins have also been shown to play a role in longevity, human longevity. And again, heat shock proteins, they don't just increase in response to heat. Exercise increases them, fasting, polyphenols, things that are part of the good stress, the good types of stress on your body, but also even bad stress, inflammation, chronic inflammation or acute inflammation can also increase heat shock proteins. So speaking to the human longevity part, it's known that humans that have a single nucleotide polymorphism in the heat shock protein 70 gene that has functional significance. So this makes the chaperone protein better at maintaining the proteins, other proteins in the cells, three-dimensional structure. Humans that have two copies of that, so they're homozygous, basically on average live two years longer than people that don't have that SNP. And people that have one copy, so they're heterozygous for that SNP, live about one year longer. So there's a gene dosage dependent effect with the HeatChuck Protein 70 SNP. so if you're one of those unlucky individuals that does not have those one or two alleles of the SNP I just mentioned, what do you do to increase your heat shock proteins? You get in the sauna. You can also be physically active. But it's been shown that healthy individuals that sit in a dry sauna that's around 163 degrees Fahrenheit for 30 minutes increase their heat shock proteins by 50 percent. And once those levels are increased, they stay elevated for about 48 hours. It's also been shown in separate studies that people that are already acclimated to heat, as in they're frequently using the sauna, or they are frequently physically active, which also raises your core body temperature, they can increase their heat shock proteins sooner upon heat stress exposure and more robustly. So people that are heat acclimated actually get a better heat shock protein response. So with that said, I will mention one more thing, one more possible mechanism by which the sauna can improve overall longevity, and that is by lowering inflammation. Multiple studies have implicated that inflammation plays a major role in the aging process, and also in age-related diseases like Alzheimer's disease, cancer, heart disease. So having something that can lower your inflammatory biomarkers is something that is good for increasing health span. And the sauna has been consistently shown to lower, for example, C-reactive protein in a dose-dependent manner. So the more frequent the sauna bathing, the more longer the duration, the more robust in terms of lowering C-reactive protein. It's also been shown to increase anti-inflammatory biomarkers like IL-10. So that's also a very good thing that, you know, something that's also very consistent with physical activity as well. Physical activity has also been shown to do the same thing. That's pretty much all I'm going to talk about today. There's lots of other things. The sauna improves. It's also been shown to have a major effect on brain function. It increases endorphins, much like physical activity, so there's a mood-enhancing effect. fact there was a friend of mine published a randomized controlled trial where he elevated people that had major depression elevated their core body temperature about one or two degrees and just one exposure to that had an antidepressant effect that lasted weeks compared to people that got the sham control which by the way the people that got the sham control thought they were actually getting the treatment, so it was a nice placebo control. It's also been shown to, there's positive things on just sweating in general. There's certain heavy metals that are excreted better through sweat than through urine, for example, cadmium and arsenic. Sorry, not arsenic, mercury. Cadmium and mercury are better excreted through sweat than through urine so there's lots of other things in terms of the sauna that i'm not going to talk about but overall um it's very it's very safe for healthy people um as well as people for with stable uh cardiac disease and it's i would say that one of the biggest biggest things that I've seen in terms of talking about the sauna in people, in the general population basically, is that people are much more likely to be compliant in terms of if you have a person that has a lifetime of being sedentary and they have risk factors for cardiovascular disease, or they may even have it, it's really hard to get them to go out and be physically active. It's very, very difficult. But when you tell them about the amazing studies that have shown that the sauna has positive effects on a variety of different cardiovascular-rated diseases and isn't good for prevention, people think the sauna is like like a spa treatment so they want to go sit in the sauna and and little do they know that it's really you sitting in the sauna is you know mimicking in many ways moderate aerobic activity so that's one of the reasons i really think i was very excited to come here and speak to all you guys physicians physicians, physician assistant, nurses, health practitioners in general, because I really think that this is something that's important to get in, you know, to have physicians talking about to, you know, other physicians and to their patients. Read the medical literature yourself, look it up, see for yourself the evidence. It's important that you rehydrate after the sauna. Typically, a person loses about 0.5 kilograms of sweat, so you have to rehydrate. I use the sauna about four times a week, and I drink a ton of water before I get in there and also when I get out. There are some contraindications, so probably one of the biggest ones is alcohol. Never, ever, ever use alcohol before you're getting in the sauna, during the sauna. There's been several case reports where it can cause death. So alcohol is a big, big no-no for sauna use. Also, elderly people that are prone to low blood pressure, because it does have a significant effect on lowering blood pressure. That's something that could potentially be a contraindication."