FoundMyFitness - #014 Sauna Use and Building Resilience to Stress with Dr. Rhonda Patrick

Episode Date: September 11, 2015

In this episode Rhonda talks about: (00:00) Introduction (03:00) Heat stress makes the body more resilient to the stresses of aging (14:45) Possible mechanisms why sauna use reduces heart disease risk (16:45) Sauna enhances athletic endurance and muscle growth (28:16) Sauna use stimulates neurogenesis and improves cognitive function and mood (37:34) Sauna use detoxifies BPA, PCBs, phthalates, and other metals (51:10) Practical applications sauna use and other heat stressors like hot yoga If you're interested in learning more, you can read the full show notes here. Join over 300,000 people and get the latest distilled information straight to your inbox weekly: https://www.foundmyfitness.com/newsletter Become a FoundMyFitness premium member to get access to exclusive episodes, emails, live Q+A's with Rhonda and more: https://www.foundmyfitness.com/crowdsponsor

Hello, brothers and sisters of the sauna. Today's episode is for you. Many of you have heard me talk in great detail about using heat stress in the form of the sauna, not only to help your body better deal with the stresses of aging, but also to enhance athletic and cognitive performance. Today, we're going to rehash a little bit of that, but we're also going to add some new information I haven't shared before. We're going to talk about how heat stress from the sauna makes the body more resilient to the

stresses of aging. Possible reasons why one study associated sauna use with up to 40% lower all-cause mortality, as well as 50% lower cardiovascular disease-related mortality. How it enhances athletic endurance, staves off muscle atrophy, improves regrowth of muscle after disuse, and some of the profound effects on the brain, including the growth of new brain cells, improvement in focus, learning, and memory, and eventually potentially ameliorating depression and anxiety. I also touch on how BPA, PCBs, phthalates, and other metals are excreted through sweat, something I haven't talked about before. Later in the podcast, I addressed some practical application questions I've received from a number

of you, like, what is the temperature and how long should I spend in the sauna? What is the difference between a dry, wet, and infrared sauna? is there an optimal timing to using the sauna? Can similar benefits from the sauna be had from steam showers, hot baths, and hot yoga? But before we dig in, disclaimer. Please keep in mind that the information in this podcast is not intended as medical advice. It is for informational purposes only and run it by your physician if applicable. Or, to put it another way, please use common sense and don't hurt yourself.

If you would like to read more about the benefits, of the sauna that I discuss in this episode, please go to foundmyfitness.com forward slash sauna hyphen report. That's found my fitness.com forward slash S-A-U-N-A-Hifin-A-R-E-P-O-R-E-P-O-R-T. If you're listening to this, it's because this episode and all of my podcast episodes are sponsored by generous people, possibly much like yourself. If you want to find out more about how you can support this podcast and in doing so, possibly garner mad respect from your bros, go to found myfitness.com forward slash crowdsponsor. That's foundmyfitness.com forward slash C-R-O-W-D-S-P-O-N-S-O-R, crowd-sponsor. And now, on to all things sauna.

I want to start off by discussing how heat stress from the sauna makes the body more resilient to the stresses of aging. Almost all of the primary causes of aging have stress at their root. Inflammation is a prime example and, in fact, has been identified as one of the key drivers of the aging process. I'll dive more into inflammation in another episode. However, somewhat paradoxically, stress isn't always bad. Short-term stress can result in a reduction in long-term chronic stress.

In other words, we can build resilience. This is because exposure to short-term stress can strengthen the cellular response mechanisms in the body to stress. This is called hormetic stress. Hormetic stress promotes longevity in part through enhanced activity of many different stress response pathways and defense mechanisms that kick in after the exposure to the hormetic stress. Some examples of phermetic stress include exercise, heat stress from the sauna, cold stress, and fasting. A recent study on around 2,000 middle-aged men found that using the sauna two to three times per week was associated with a 24% lower all-cause mortality and using it four to seven times per week

was associated with a 40% reduction in all-cause mortality compared to men that only use the sauna one time a week. So there was a dose-dependent effect, meaning the more frequent the sauna use, the lower all-cause mortality that occurred. Because this is an association study, no causality can be established. However, the dose-dependent nature of the effect dramatically strengthens the study. So we must turn to animal studies in order to establish causality. Just one exposure to heat stress in flies and worms has been shown. to increase their lifespan by 15%. The mechanism for this has been shown to be dependent on something called heat shock proteins.

In fact, another study recently identified that aging is caused by a molecular switch about eight hours into adulthood of a worm that deactivates heat shock proteins. So when heat shock proteins are deactivated, this causes rapid cellular aging in C.L. which are tiny roundworms. They have an average lifespan of around 15 days. Heat stress from using the sauna also from exercise activates a genetic pathway in the body that activates heat shock proteins, also called HSPs. And it's been shown that being heat acclimated, so the more you expose your body to heat through exercise, routine exercise, by using some of the something like a sauna, regular sauna use.

This results in the production of more heat shock proteins under just normal temperature conditions. And when a stressful condition occurs, the body makes even more heat shock proteins. So a stressful condition like cell or tissue injury, for example. And this is really good because as very similar to worms, as humans age, humans also make less heatchalk proteins. So anything that can boost them, boost the amount that they're activated, the amount that you're making them is beneficial. So what are heat shock proteins? Well, heat shock proteins have many important functions inside the cell. One very important function is to make sure that proteins, which are inside of your cell, proteins do all of the work. So

your DNA is like the genetic code. It's a blueprint, which makes RNA, and the RNA gets translated into proteins. And the proteins are doing everything in your body. So they're very important. And each protein has a certain three-dimensional structure inside the cell, and that three-dimensional structure is very important for the function of the protein. And when the cell is under stress, whether that's a stress from injury or just the stress from normal aging, chronic inflammation, the proteins become damaged. And when they become damaged, it screws up their function and also can disrupt the ability of these proteins to be degraded or get the mechanism by which the body gets rid of a protein

after it's served its function and then you make a new protein to replace it. That's very important. But if you can't get rid of the protein, then the protein sticks around. and it sticks around for a longer time than it should be and can start to cause more problems. So it can actually start to aggregate with other proteins in the body and form plaques. So, you know, this is, the protein aggregation is associated with many different diseases, cardiac diseases, including heart failure, cardiomyopathy, atherosclerosis, as well as, and probably most prominently with neurodegenerative diseases,

such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Increased expression of heat shock proteins has been shown to prevent protein aggregation. And the reason for that is because heatchalk proteins help repair damaged proteins. And of course, it's not surprising that heatchalk proteins have also been shown to protect against nerve degenerative diseases like Alzheimer's disease. So these heatchalk proteins are very important because they're maintaining. maintaining a certain, maintaining the, making sure the proteins inside of your cells keep their structure are, you know, get, are, you know, degraded in the right way when they're supposed

to be or when they're damaged, they're, make sure that the protein structure is properly maintained so that their protein doesn't have to be degraded. Hitchcock proteins are also linked to human longevity. So humans with a gene polymorphism, which is just a variation in a sequence of DNA that can alter the function of the gene in a certain way, are associated with, so polymorphisms and heat shock proteins that are associated with producing more of the heatchog protein is also linked to having a increased chance of being a centenarian, which just means living to be at least 100. So that's pretty cool. And I'm going to talk more about heat shock proteins in a little bit when I talk more about athletic endurance.

But back to the longevity aspect and building these stress tolerance pathways, another one that's robustly activated by heat is a pathway called FOX-O-3. And FOX-O-3 is the so-called longevity gene. It's been, so humans with the polymorphism that make more of FOX-O-3 have up to a 2.7-fold increased chance of living to be a centenarian. Worms that make more of the worm version of FOXO3 can extend their lifespan by 50%, 50% up to 100% even in some cases. In mice, mice that have more FOX-O-3 can also extend their lifespan by up to 30%. So why is this? Well, Box O3 is a gene that activates a plethora of other genes in the body that are responsible for stress resistance. And what that means is these genetic pathways are responsible for repairing damage, any type of damage, lots of different types of damage that occur. Damage that happens to the DNA. which is associated with causing mutations in mitochondrial DNA and also in nuclear DNA,

it's not good to have DNA damaged. DNA damage causes all sorts of problems. It's linked to cancer and also to aging. So Box O3 gene activates a whole host of genes that are able to repair damage that happens to DNA before it can cause mutations. So that's a very important function of FOXO3. The other thing FOXO3 does is it activates a plethora of genes that are involved in scavenging oxidative damage, so antioxidant-related genes.

So the damage never actually reaches the cell because these antioxidant genes scavenge the reactive oxygen species or detoxify some of the, some of the, some of the, damage that's done. So that's really important. Another thing that happens that, or another pathway that Foxo3 activates is a pathway that is able to clear away damage cells. So the process of clearing away a damaged cell is called autophagy. And autophagy is very important because when you have a damaged cell, this can lead to a senescent cell, which basically means a cell that doesn't die, it's still alive, but it's not really doing its function. And it's just sitting around inside of your tissue, whatever tissue we're talking about, liver tissue, heart tissue, blood cell,

so on. And it's just producing pro-inflammatory cytokines and other factors. that damage other nearby cells. So it's kind of just like sitting around secreting these other inflammatory molecules that are then damaging other cells that are nearby. So it's sort of magnifying the damage. So clearing away those damaged cells is really important and that happens through a process called autophagy.

Box O3 activates genes that enhance atophagy. So that's also very important. Another thing that Foxo3 does, is it activates genes that are involved in immune function. So immune function declines with age. You know, your... So activating genes that are involved in immune function is very important for fighting off bacterial, viral infections,

also for clearing away cancer cells. So FOXO3 regulates genes that are involved in immune function. In addition to that, FOXO3 also regulates genes that are involved in stem cell function. So making stem cells grow and divide more, which is also important because stem cells are very important for replenishing various cellular populations in different tissues. And as we age, we lose stem cell function. As we lose stem cell function, we're not going to be able to replenish damage cells, and

that leads to organ dysfunction ultimately. So Boxo3 is pretty awesome. I could go on and on. It's, you know, it's been shown in many different animals to regulate longevity. The more you have of it, the better. So heat stress from the sauna activates FOX-O-3. Exercise also activates FOX-O-3. I'm going to circle back to the same study on 2000 middle-aged men, which also found that fatal cardiovascular disease was 27% lower for me. men who use the sauna two to three times a week and 50% lower for men who use the sauna four to seven times a week compared to men who only use the sauna one time or week.

I think it's important to point out here that sitting in the sauna, the heat stress from the sauna, to some degree mimics cardiovascular exercise. So some of the positive benefits of the sauna, on heart health may have to do with similar benefits seen with regular physical exercise. So when you sit in the sauna and start to become really hot, heart rate starts to increase. And I've experienced this, you know, every time I'm in the sauna, every time I'm exposed to heat stress, heart rate can increase even up to 100 beats per minute during moderate sauna bathing and actually can go up to 150 beats per minute during a more intense sauna session, meaning the hotter the sauna, the longer you're in there, which is really fast.

And actually 150 beats per minute corresponds to moderate intensity physical exercise. So I think that to some respect, some of the cardiovascular benefits from the sauna have to do with the fact that the heat stress does sort of mimic cardiovascular exercise to some degree. and the sauna has been shown to improve blood pressure, endothelial function, left ventricular function, things like that. So it's not too surprising to me. And this sort of leads me into the next topic, which has to do with the effects of heat stress on athletic endurance. Okay, so now I'm going to dive into how heat stress from using the sauna can enhance athletic endurance. I call this hyperthermic conditioning. So there are a few physiological adaptations that occur once the body has repeated exposure to heat.

This is also called heat acclamation. And heat acclamation is able to enhance endurance by three mechanisms. One mechanism is by increasing the plasma volume and blood flow to the blood flow to the the heart. This is often referred to as stroke volume. So when you have increased plasma volume and blood flow to the heart, this results in reduced cardiovascular strain, which means that for every beat your heart pumps out the blood, it has to do less work because of the increased plasma and blood flow. So it's been shown that these cardiovascular improvements have been able to enhance endurance in both highly trained and untrained athletes. The second mechanism is by increasing

blood flow to your skeletal muscles. So increased blood flow does not just happen to the heart, but it happens to a variety of other tissues in the body, including the skeletal muscles. So your red blood cells are carrying all sorts of goodies, you know, glucose, hysterified, fatty acids, oxygen, and these goodies are getting delivered to skeletal muscle quicker if you're having increased blood flow. And so it has been shown that when your people that are heat adapted, once they exercise, which also increases heat, core body temperature, the mechanisms kick in and increase blood flow to the heart occurs, increased blood flow to the skeletal muscle muscles occur, and also increase blood flow to the skin.

And this leads me to the third mechanism, which is heat stress actually improves thermoregulatory mechanisms, which basically means that your body is able to cool itself quicker, and part of the way it does that is by increasing the blood flow to the skin, which causes perspiration. So people that are heat-adapted start to sweat at a lower core body temperature, which then cools them, dissipates the heat, and then they can maintain their endurance performance or their endurance physical activity for a longer period of time, mostly because they're not so physically uncomfortable that they want to stop. So that's also another mechanism by which being heat adapted, so using the sauna to basically increase these physiological adaptive mechanisms to kick in for the next time that you are elevating your core body temperature, which is by some sort of endurance, you know, athletic performance or activity.

There have been a few studies. There are small studies that have shown and demonstrated that being heat adapted. can enhance endurance. For example, there's a study that showed a 30-minute sauna session two times a week for three weeks after a workout could increase the time it took for the participants to run until exhaustion by 32% compared to baseline. And there are other examples out there as well. But in addition to the athletic endurance, heat stress from the sauna also has profound effects on muscles, and particularly in staving off muscle atrophy, as well as improving regrowth of muscle after disuse, so disuse meaning after an injury, if you're not putting any sort of workload on

the muscle for a period of time. And there are a variety of mechanisms that regulate this. One of them happens to be heatchalk proteins. So I'm going to dive a little bit more into the heatchalk proteins. But first I want to just mention a couple of the studies that have been done in rats showing this. So, for example, rats that were exposed to a 30-minute kind of like a little rat sauna where they put the whole rat in this little chamber and the heat heated up to around 100, 105 degrees Fahrenheit or 41 degrees Celsius. And this, you know, so the 30-minute exposure to this heat was able to stave off muscle atrophy during disuse.

And that's been shown to be dependent on the activation of heat shock proteins, specifically heat shock protein 32, heat shock protein. heat shock protein 25 and heat shock protein 72, which are all robustly expressed in the soleus muscle and muscle tissue in general. And the expression of these heat shock proteins maintain for several days after the initial exposure to heat. Another rat study showed that exposure to this little rat kind of sauna, again, same temperature after muscle disuse for about seven days.

So the hind limb of the rat was, there was a little cast put on the hind limb so that the rats couldn't use that muscle for a week. And then after a week, the little cast was removed, and then the rats were able to move around. And those rats that were exposed to either a 30-minute or a 60-minute little sauna treatment, or heat stress treatment, were able to regrow their muscles 20% faster or 32% faster. So 20% faster if they were exposed to a 30-minute heat treatment and 30% faster if they were exposed to a 60-minute heat treatment.

And this is faster than the rats that were not exposed to any treatment before having their muscles, before disuse of their muscles. So there is definitely relevance for muscle injury, and I've definitely experienced this firsthand several times when I've injured a variety of different muscles and not been able to do my usual workout, sitting in the sauna. In some cases, I was obsessively using the sauna, probably a little overboard seven days a week in some cases. I noticed that I lost less muscle mass than previous times.

of not using or being injured and not using being able to work out. Of course, that's entirely subjective. But let's talk about some of the mechanisms by which the staving off muscle atrophy and the improved regrowth after regrowth of muscles after disuse occurs. So there's really three mechanisms by which this occurs. And the first mechanism is the robust activation of heat shock proteins. And in fact, those rat studies that I just explained in those same studies, the prevention of the muscle atrophy was shown to be somewhat dependent on activation of these heat shock proteins. So as I mentioned previously, heat shock proteins are very important for repairing damaged proteins. And a damaged protein, if it's not repaired, can either get degraded

rapidly or it can not get degraded and it kind of just sits around and can start aggregating with other proteins and it's still not functional. So because heatchalk proteins repair these damaged proteins and make sure that their three-dimensional structure is correct, it prevents these proteins from being degraded. And in the case of muscle tissue, that's a good thing. In addition, Heat-Chalk proteins also can prevent damage from happening by scavenging free radicals and by increasing different antioxidant pathways that are able to, for example, maintain glutathione inside cells. So heat-ogic proteins are pretty important for maintaining muscle mass.

And another mechanism by which heat stress can prevent muscle atrophy is by robustly activating growth hormone. And growth hormone activates this downstream pathway of IGF1 in muscle tissue specifically you can activate IGF1. And IGF1 is able to prevent muscle atrophy because it activates this whole other pathway called mTOR which is responsible for protein synthesis. So you're making new proteins. And it also inhibits a path to. pathway that degrades proteins. So, and that's through a pathway called AKT. I don't want to get all nerdy and too technical, but the bottom line is that by growth hormone activating IGF1 in the muscle cells, both protein synthesis increases and protein degradation's inhibited.

So that's also very important for preventing muscle atrophy and maintaining muscle mass. And I think has huge applications, particularly for muscle disuse, for aging, et cetera. The third way by which heat stress from the sauna affects muscle growth and atrophy is by increasing insulin sensitivity in muscle tissue. So increasing the insulin sensitivity in muscle tissue. tissue then also increases protein synthesis by stimulating the uptake of branched amino acids in the skeletal muscle, and also it decreases the degradation of proteins, much like the IGF1. And it increases the glucose transporters on muscle tissue. So the glucose transporters on muscle

tissue, specifically the glute four, which take the glucose from the bloodstream and bring it into the skeletal muscle. All right, so that's the muscle. So now I want to shift gears and talk a little bit about some of the really profound effects that heat stress have on the brain, including the growth of new brain cells, improving focus, learning, memory, and ameliorating depression and anxiety. So heat stress has been shown to increase the expression of brain-derived neurotrophic factor, also known as BDNF, more than just exercise alone, which also increases BDNF.

So when heat stress and exercise are combined, more BDNF is released in the brain than just exercise alone. This is really important because BDNF increases the growth of new brain cells. it also increases the survival of already existing neurons. In addition to being very relevant for aging, because as we age, we lose the ability to make new neurons. You know, those mechanisms are not occurring as well. Brain atrophy occurs, things like that. In addition to that, increasing neurogenesis is also or has also been linked to enhanced learning processes.

The other thing that heat stress from the sauna does is it increases the release of noraepinephrine in the brain. Not only does it increase the release of noreepinephrine, but it increases the capacity to store norepinephrine for later release. Now, noreepinephrine helps with focus and attention. it also is related to mood and improves, has been shown to improve mood. On the topic of mood, something else that heat stress from the sauna does. In fact, the sauna has been shown to cause a massive release of beta endorphins in the brain,

which is the body's endogenous opioid neuropeptides that are often associated with feeling good. But I want to talk about something that I find even more interesting. And this is really what got me and got me interested in this sauna in general was I began using the sauna quite frequently because I basically lived across the street from a YMCA when I was in graduate school. And so I started doing the sauna early in the morning before going into the lab, before going to work before doing my experiments. And I noticed that using the sauna before I started my day had a profound effect on my mood and on the ability for my brain to handle stress. For example,

you know, being a scientist, probably around 80% of the experiments that you perform fail and it's very frustrating and you have to troubleshoot and figure out what's wrong and you know there's lots of little details involved but the main thing is that it's very frustrating and I started to notice that getting in the sauna before going to work and having those failed experiments happen I began to like it the stress of of that didn't affect me as much And not only the stress from being frustrated from failed experiments, but the stress from social pressure, from, you know, the social interactions that, you know, failed experiments don't work. Well, people are relying on you and they put more stress on you and it's just,

and you know, there's lots of stressful, stressing types of factors involved. And I noticed when I stopped during the sauna, or actually before I started using the sauna, I should say, clarify, I was a mess. It was completely stressed out. And doing the sauna really, really helped me deal with that stress. And I became very interested what physiologically was happening because it was a very, very notable change in my brain function, in my mood, in my ability to handle the stress.

So I started diving into the sauna literature. And that took me on this whole path where I began doing this research for a couple of years. And one of the things that I found very interesting is that heat stress from the sauna, because you are elevating your core body temperature, your body has a physiological response to that by trying to cool itself. So in addition to the sweating mechanisms, there is also something going on in the brain. And what that is, is mediated through a pathway that's called dinorphin. Dynorphin is also your body's endogenous opioid that is the counter to endorphin.

And what I mean by that is that it is not responsible for feeling good. It's actually responsible for that dysphoric feeling. So dinorphin is like the counter to endorphin. And the reason why you make a lot of dinorphin when you sit in a sauna and when you're elevating your core body temperature, which can be extended to exercise, of course, is because dynorphin cools the body. In fact, when you inject dynorphin into rads, it rapidly cools their body temperature. So the reason why the body starts to make, produce dynorphin is because of the role

that it has in cooling the body. But that's not what's interesting. What's interesting is that, so that feeling of discomfort when you're really hot and you're just, you know, you're uncomfortable and you're just like, oh, I got to stop doing this, that disworked feeling. That's an orphan. And like I said, that's also extended to, you know, intense exercise when you start to really, like, you're working out hard and you reach that point where you're just like, oh, God,

it sucks, you know? That's dinorphine. And dinorphin binds to a receptor called the Kappa opioid receptor. That's how Dynorphin exerts its function by binding to the receptor. And what's really interesting is that the binding of Dynorphin to the Kappa opioid receptor in the brain causes a sort of a feedback response in these other types of opioid receptors in your brain. called mu-opioid receptors. Mew-opioid receptors bind the feel-good beta-endorphin.

In fact, mu-opioid receptors are the biological target to many opioid drugs, morphine, for example, or morphine derivatives. So what happens when you activate that dinorphin pathway and you activate that cap-opoeuvreous receptor is your body starts to go, oh my God, this is awful. I need to counter this with some of that feel-good stuff. So your brain starts to increase the amount of mu-opioid receptors in the brain, and it sensitizes them to endorphin. What that means is that when your body then dumps endorphins,

which happens when you exercise, which happens with the sauna, Once you get past that dysphoric feeling, you're going to feel really good. And the reason you're going to feel really good is not only because you're producing a, you know, crap ton of beta endorphins, but it's because you have more receptors to bind to those beta endorphins to feel its effects, and they're sensitized. So you actually need less of it. And so this, I've come to the conclusion, back to my personal story here, The lasting of, this is a lasting effect.

So, you know, yeah, you dump out a bunch of beta endorphins when you exercise, you dump out a bunch when you're in the sauna, but that's a short-term effect. Once you dump them out, they're gone. You know, they only last for a certain amount of time. But when you increase the amount of receptors that bind to beta endorphins and you sensitize them, that means throughout the day, anything else that causes a release in your beta endorphin, you're going to be more sensitive to it. And you're, so you're basically going to have lasting effect.

from the beta endorphins. And I really think that's probably the bottom line with the effects of heat stress and the sauna on mood and on the ability to, for your brain to be able to deal with stress. I think it's largely mediated through this activation of the dinorphine pathway, which, like I said, the reason it's activated is because it cools the body. And that's all very interesting. But with that said, I'm going to end on my brain effects of the sauna and I'm going to talk about something that I have not talked about previously and that I'm just going to touch on it.

And that is how using the sauna to sweat can cause your body to excrete different xenobiotics, which are compounds or drugs that are foreign to the body and also different heavy metals. So sweat contains both hydrophilic compounds, which are water soluble, and are excreted through sweat glands, but it also contains lipophilic compounds, which are fat soluble, and are excreted through the sebaceous glands. So there's a few compounds that I'm going to cover, BPA, PCBs, and phthalates, as well of some other heavy metals. Bisfenal A, or BPA, is widely found in a variety of plastics, plastic bottles, plastic packaging, the linings of food and beverage cans, dental composites and resins that are used

to fill cavities, as well as are. for, used for other cosmetic uses. If you have any feelings in your teeth that are not silver color, then you likely have composite with some BPA in your mouth. A BPA is also used in thermal paper used in cash register receipts, store and fast food receipts, airline tickets, ATM receipts, you get the point. It has been shown that using a skincare product like cream or a sanitizer and then touching a store receipt with BPA, and it causes a rapid increase in BPA immediately in blood. So if you happen to handle paper receipts on a regular basis for your job,

I highly recommend wearing some sort of glove, nitrile, or latex, or what have you. While BPA can leach into fluid at normal room temperature, heat dramatically, increases that event. So, for example, and the most extreme case, boiling, increases the leaching of BPA from a plastic container into the liquid by 55-fold. Also, it's been shown that BPA exposure levels not only increased with temperature, but also with repeated use of a container. For example, buying boxes. bottled water and just continuing to reuse that same plastic bottle. Once BPA enters the bloodstream, it's thought to be modified in the liver in this reaction

called the conjugation process. And that conjugation process decreases the half-life of BPA to approximately five hours. So people generally are not worried about BPA because it's thought, well, your liver will detoxify it, conjugate it, and it becomes, you know, non-active. However, the placenta of humans contains an enzyme called beta glucuronidase that is present and modifies BPA back to its unconjugated active form immediately. And this is very important because it's plausible that during pregnancy, the conjugated form of BPA will circulate through the placenta, undergo deconjugation, so it's now

active again, and cause subsequent fetal exposure in utero. And I think this may be the reason why many of the adverse health effects due to BPA exposure have been found to occur during fetal development. Some of the negative health consequences that have been shown to result from BPA exposure in some form or another. For example, a single exposure to BPA has been shown to raise BPA levels by 16-fold in urine, increase blood pressure in people, and BPA is known to block certain estrogen receptors that are thought to be responsible for repairing blood vessels and controlling blood pressure, so that may be part of the mechanism by which that occurs.

BPA exhibits hormone-like properties and has been linked to many different reproductive defects in fetuses, infants, children, and adults. It's also been linked to hormone-related cancers like breast cancer and prostate cancer. It's a suspected risk cancer for breast cancer through its action as an estrogen memetic. And mouse studies have shown BPA can cause endocrine, metabolic, and immune problems in cancer. pregnant mice that were exposed to levels of BPA equivalent to those considered safe in humans, meaning below the FDA levels for being safe, caused reproductive and hormonal defects that actually lasted for three generations in mice.

So I want to also talk about these BPA replacements. I want to keep in mind that exchanging one chemical for another is not always a good thing. BPA substitutes are always advertised in these BPA-free products. Well, those BPA-free products have also been shown to leach chemicals that have estrogenic activity, and sometimes these chemicals have been shown to actually be even more potent than BPA. So, again, exchanging one chemical for another, not necessarily a good thing. But now that we're all terrified of BPA, I want to talk about something positive, and that is BPA is excreted through sweat and perspiration. And the sauna is a great method of inducing the excretion of BPA through sweat.

Exercise is another great way to excrete BPA. Basically, sweat. You need to sweat. PCBs, so polychlorinated biphenols. They are organo-cloering compounds that were previously used. I say previously because they were banned something like the 1970s. And so they were previously used in like a bunch of industrial and chemical applications, like cool-ins, insulators, in transformers, capacitors, motors.

But despite they're being banned, they still persist in the environment. In fact, many freshwater fish and farm fish are contaminated with PCBs. Some of the inverse human health effects of PCBs are endocrine disruption, particularly in the developing fetus. Again, it's also been linked to hypertension, much like BPA, as well as some types of cancers. PCBs are lipophilic, so they're fat-tiable, and they tend to. accumulate in human adipose tissue. They also accumulate in muscle tissue fat. So in both humans and animals, such as fox, rodeo, I mentioned fish. Many food products such as butter, dairy products, meat, even eggs, have been shown to be contaminated with PCBs. So they are ubiquitous. They are in our

food, they're in our water, they're in our fat, they're everywhere. They also have been shown to reach the brain, the liver and the lungs. And unfortunately, PCBs have a very long half-life, very long, ranging anywhere between four to nine years. So that's unfortunate and probably is part of the reason why they're so persistent in our environment despite being banned in the 1970s. But it's not all bad. Some PCBs, not all PCBs, there are a variety of different kinds of PCBs, have been shown to be cleared through perspiration. Again, so the sauna induces sweating, exercise induces sweating. So sweating, you know, has shown to clear certain PCBs. And that's good news. Phallates are

Another type of man-made compound that are ubiquitous in plastics. They're used to create, to make plastics more soft and malleable. They're also used in a variety of other consumer products, fragrances, paint, nail polish, plastic wrapping on food and beverages. They're pretty ubiquitous in terms of soft plastic toys. They're in vinyl, floor tiles, shower curtains, synthetic leather, shopping bags, pharmaceuticals. You get the point. They're everywhere. Multiple urine samples analyzed from populations worldwide have found that these phallates

can be found in like 98% of participants, so including pregnant women. These thallates have a relatively short half-life, less than five hours, which means really that the fact that they can be detected in 98% of the participants isn't as a consequence to bioaccumulation, but it's a consequence to really just chronic exposure to them. Like I said, I mentioned, I rattled off like almost every consumer product out there they're in. And so, you know, we're just, we're chronically being exposed to these things. I don't want you people to freak out. I mean, this is like, I'm just, you know, these are not, like, the main concerns for health. I don't focus on these main concerns because I don't think they're the primary health concern. But they are something to think about.

So I just am mentioning this mostly because there's light at the end of the tunnel and that is they can be excreted through sweat. And just another reason why exercise is so good for you and also why the sauna is good. Back to these phthalates, they have been shown to lower testosterone levels and also block the effects of testosterone in organs and in tissues. And they can be passed from mother to fetus through the placenta, resulting in abnormal sexual development. Again, so some of these thalates, but not all of them, can be excreted through. sweat. So get out there in sweat. Use the sauna, exercise. I'm going to shift and talk a little bit about some heavy metals, arsenic, cadmium, lead, mercury. I'm not going to talk all about negative health effects of being exposed to high levels of these, but I am just going to say that

all of these metals have been shown to be excreted in sweat. So the key here is sweating. sauna induces massive sweat fest, but exercise also does, so get out there in sweat. So in addition to dumping out all those nasty compounds like BPA through your sweat, excessive sweating also causes a loss of good things, water, for one, obviously, but also electrolytes such as sodium, potassium, magnesium, chlorine, these also are excreted in sweat. The sauna makes you sweat a lot. So you can imagine you're, in addition to losing a lot of water, you're losing a lot of electrolytes. It's a really important after sauna, after using the sauna, to drink plenty of water and to replenish electrolytes.

Coconut water has been shown in peer-reviewed studies to effectively replenish electrolytes after excessive sweating. or the other thing you can do is just blend up some spinach and chard or some kale with some water because those plants also contain a ton of sodium, potassium, magnesium, chlorine, all the electrodes you need, as well as other vitamins and minerals. So that's what I do. I like to blend up. I make a smoothie after I have an intense on a session. So bottom line, make sure that you replenish your water and your electrolytes by whatever means.

So now I'm going to sort of dress some practical applications, some questions, very common questions that I've gotten regarding the sauna. Starting with the difference between a dry sauna, wet sauna, which is also known as a finish sauna. and infrared sauna and far infrared sauna. I'm not going to go too much into detail on this. A dry sauna typically refers to a wood panel broom with wooden benches and a heater that heats the air up, anywhere between 158 to 194 degrees Fahrenheit

or 70 to 90 degrees Celsius. And a wet sauna, it's basically a dry sauna, but water is poured onto hot rocks, which then produces steam and raises the humidity in the air to like 20% or something like that. So it creates a moisture in the air. And in both the dry and the wet sonnas, the heat is transferred from the air to the body. So the major difference between a dry or wet sauna and an infrared sauna is that the drier wet sauna heats the air up, and this heat is transferred from the air to the body, whereas an infrared sauna uses thermal radiation, which is electromagnetic radiation that is generated by moving particles in matter.

And in this case, the matter happens to be our bodies. So infrared sonnas heat the body directly without necessarily needing to warm the surrounding air. The air does get heated but not nearly as hot as a traditional dry sauna. So there are two main types of infrared sonnas. There's the infrared and the far infrared sauna. Really not going to go into too much detail on this. But the infrared sonnas typically use heat lamps, which are incandescent bulbs. And those produce thermal radiation primarily in the near infrared wavelength with a lesser amount of middle infrared wavelength. Bar infrared sonnas use typically a ceramic or a metallic heat element that emits energy

in the far infrared range, which is actually similar to the sun. I have seen much more marketing claiming that infrared saunas induce more sweating than actual science. And personally, I've experienced the opposite effect. But all the benefits that I have discussed today on longevity, the cardiovascular benefits, the endurance benefits, on preventing muscle atrophy, on the brain, all the benefits, with the exception of the excretion of xenobiotics from sweat have nothing to do with sweat and have everything to do with heat stress and the physiological adaptations that occur as

consequence of heat stress. So while I think infrared sonnas are great, particularly far infrared saunas because there's more science showing some positive benefits and effects of far infrared saunas on cardiovascular disease. I think they're great for the home, mostly because these infrared saunas pose much less of a fire hazard than a dry sauna. But I don't buy much into the sales marketing that I've read about them. So personally, I think the inferenceanas are great,

but I don't think they're superior to traditional dry saunas. And in fact, that's just because it's the heat stress that's important for many of these effects. And, you know, until more science comes, out proving otherwise, you know, I'm not convinced. So next question. What about the duration frequency timing of the sauna? If it's a typical sauna, like a dry sauna or a wet sauna that's really hot, somewhere between 170 or 180 degrees Fahrenheit or 77 to 82 degrees Celsius, then a duration of around 20 to 25 minutes is really

what most studies have shown to be beneficial. And I typically stay in for about 25 minutes in a really hot sauna. As for the frequency, as I mentioned previously, there's a dose-dependent effect on both all-cause mortality and on decreasing cardiovascular-related mortality. So four to seven times per week was better than using it two to three times per week. most of the studies on endurance and muscle atrophy were in the two to three time per week range, which is, I think, for me, at least, doing it three times a week is more reasonable.

In terms of timing before, after a workout, all the studies that I spoke of today were done either after a workout or on days with no workout. I tend to do both of these. practically speaking, doing the sauna immediately before a workout seems just awful. Really, who wants to be drenched and sweat and exhausted before the start of a workout? So I think it's pretty common sense. What about using the sauna during muscle injury? Well, as I mentioned, rats that were exposed to a 30-minute heat treatment or, yeah,

It was a 30-minute heat treatment at around 105 degrees Fahrenheit or 41 degrees Celsius, increased their muscle regrowth and their soleus muscle by 30% after disuse, muscle disuse for seven days compared to rats that were not heat-treated. So personally, like I said, I've experienced something similar, and I do think that using the sauna may be a good way to stave off muscle atrophy, you know, whether we're talking about injury or also with a pain. aging, with aging using the sauna in combination with strength training, I think is a great combo. What about other methods of heat stress, like the steam room, hot bath, or hot yoga, can sauna

benefits be had from other methods? The scientist me will tell you this. There's no direct comparison between any of these methods. All of the research studies that I referred to use a dry or a wet sauna, which is why I mentioned them. But the basic idea here is to use heat stress, to activate stress response pathways, such as increased heat jug proteins, growth hormone, box O3, the improved blood flow, which all help the body deal with stress and also repair damage better. I think that steam rooms, steam showers, which have moist heat and a very high humidity, are also a form of heat stress.

I've used steam showers before, and I found that I experienced similar effects like elevated heart rate, feeling uncomfortable, et cetera. The same goes for hot baths if I sit in them long enough and they remain hot. I think that hot baths also can induce some of the same physiological responses. It is a form of heat stress. I don't feel like the effects are as robust with a hot bath as I do with a steam shower. Definitely not as robust as a sauna. But that's completely subjective.

No studies to prove or disprove that yet. It is a form of heat stress. And like I said, if you're sitting in a hot bath for long enough and it remains hot, you will start to feel your heart rate elevating, which is one of the physiological responses to heat stress. hot yoga or bickram yoga is usually done around 100 degrees Fahrenheit, usually, or 38 degrees Celsius with about a 40% humidity, which makes it feel hotter than it otherwise is, or would be. And I do think that many of the benefits from the sauna can be applied to hot yoga, not to mention that yoga itself causes you to physically exert yourself, which is also.

inducing a lot of these heat stress response mechanisms. So basically I think steam showers, hot yoga, hot baths, if done right, are other ways of heat stressing the body and will likely activate many of the same stress response pathways as the sauna. I'm not sure if the effects will be as robust as the sauna, but the heat is the important factor here. While regular sauna use is known to result in a number of therapeutic benefits, many of which I discussed, it is still a stress on the body and caution

should be taken. Do not drink and sauna. Drinking alcohol while in the sauna or even immediately before is the number one most dangerous health risk associated with sauna use. Alcohol consumption while in the sauna can cause severe dehydration, hypotension, arrhythmia, and possibly embollic stroke. I repeat, do not drink alcohol and then get in the sauna. If you have any medical conditions, consult your physician, and if you're pregnant, it's probably best to stay out of the sauna. Okay, all that said, this concludes this episode of the Found My Fitness podcast. But before you go, I also want to take a minute to try and explain why I started Found My Fitness. It started as a simple collection of articles that I wrote as a way to break down and explain

the right choices that people could make for a healthy life. and this was really not only just a way to document my own journey, but in doing so, I hoped it would also help make those conversations with friends and family that I desperately wanted to have just a little bit easier. We all have somebody in our lives whose health and even well-being is a train wreck, at least partly, if not mostly, from their own doing. By creating an article or a video, is able to talk with them, share a little bit of information at a critical moment, and instead of indemnating them with information and being them over the head, which usually doesn't work, and, you know, they only may be somewhat receptive to.

I could tease them with a little bit of a conversation and offer to email them a link describing in great detail what exactly I wanted them to know. This has really evolved over time and now I make videos as well because, as it turns out, video has a way of convincing people to pay attention when an article won't. This effort is not without its own set of difficulties, though. If I want to reach those people who need the information the most, most, but most of the time they don't know they need this information the most. I have to try to put up as few barriers as possible to those people.

My goal will always be to try to produce as much of my information as free as possible. In other words, found my fitness is a labor of love. Whether we're talking about the weekend, the evening, or even 1 a.m. on a weekday, trying to finish a video off for a successful release the next day, I'm on the job. And I love every minute of it. It's very exciting to me to have something new to bring to the discussion, and it's incredibly rewarding when I get feedback on social media or emails from all of you. Thankfully, I'm not in it alone.

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