[Transcript] – Fire & Ice: Tips, Tricks & Biohacks To Maximize The Benefits Of Sauna, Hyperthermia, Cryotherapy & Cold Thermogenesis.

Affiliate Disclosure


From podcast: https://bengreenfieldfitness.com/podcast/lifestyle-podcasts/hot-and-cold-therapy/

[00:00:00] Introduction

[00:01:49] Podcast Sponsors

[00:05:13] How Ben Got Started Using Hot and Cold Therapy

[00:10:38] Ben's Sadistic Foray into Hyperthermia

[00:15:16] The Endurance Benefits of Heat

[00:18:58] Muscular Benefits of Heat

[00:26:45] Longevity Benefits of Heat

[00:27:34] How Heat (Or Leaving Heat) Promotes Brain Health

[00:32:02] Podcast Sponsors

[00:35:25] Tips and Tricks to Enhance Your Sauna Experience

[00:42:53] How Cold Affects the Brain

[00:49:46] Inflammation and Immune System Benefits of Cold

[00:53:12] The Effects of Cold on Aging

[00:54:16] Cold's Effects on Fat Loss

[00:58:24] Performance and Recovery

[01:03:42] Tips and Tricks to Enhance Cold Thermogenesis

[01:10:14] Closing the Podcast

[01:11:30] End of Podcast

Ben:  On this episode of the Ben Greenfield Fitness Podcast.

As a college student, and I pretty much did all my bodybuilding via sweat, blood, tears, creatine, and some really nasty tasting protein shakes. That's something that's been known for a while, and that's of course a gimmie when it comes to anti-aging tactics. Any exercise that's intense because your body heat's going to go up anyways is going to feel way easier. That dynorphin is kind of a fantastic bonus of the regular sauna. A five-minute hot/cold contrast shower, that's an example of how little you need to get some of these benefits.

Health, performance, nutrition, longevity, ancestral living, biohacking, and much more. My name is Ben Greenfield. Welcome to the show.

So, today's podcast, it's–gosh, I think you're going to really dig this one. I don't think there's ever been a comprehensive podcast done on all of the benefits and the logistical ins and outs of incorporating a robust heat and cold practice in your life. I dug deep into the research for today's show. I think you're absolutely going to love it. It's a solosode with me. Everything you hear about the research studies, the best practices, the products, the books, the additional podcasts, everything, you're going to find at BenGreenfieldFitness.com/hotandcold. That's BenGreenfieldFitness.com/hotandcold. And put on your thinking caps and get out your notebook for this one because I'm going to give you everything you need to know for the fat loss, for the cognitive benefits, for the immune-boosting benefits, and beyond when it comes to heat and cold. I will tell you how long, how much, how hot, how cold, everything. So, if you're in the mood for upgrading your sauna or your cold thermogenesis practice, this podcast is for you.

What's cool is that one of the things that I use on a regular basis is actually colostrum. And not only can colostrum reduce the amount of gut permeability, especially in athletes or active folks when they're exercising in the heat because that's a common issue and people exercise a lot. They get leaky gut. And you pile on top of that the fact that active people got to eat more calorie throughput. It becomes an issue. I struggled with a lot when I was racing Ironman triathlons in extreme heat. And I did a bunch of research into what could reduce gut permeability in the heat, and what could reduce gut permeability in athletes overall. And it turns out that something called colostrum is pretty much the number one way to do that.

For example, there was one recent randomized control trial on healthy adults, and they showed that one gram a day of colostrum for 20 days could reduce levels of stool zonulin. Now, stool zonulin is the gold standard marker of gut lining permeability. So, this showed that you were actually restoring the health, and particularly the gut lining with regular consumption of colostrum. They only use one gram a day. One serving of our Kion Colostrum is 3.2 grams, one tiny scoop. It's a totally bioactive powder. No capsules. You completely absorb all the nutrients. We minimally process it to preserve all the fragile nutrients, and proteins, and peptides, and especially the very bioactive component called lactoferrin, and a lot of companies do not have appreciable amounts of lactoferrin in their colostrum. And so, if you struggle with gut issues, with leaky gut, with feeling like you get bloating or gas, or just kind of a blah feeling during your workouts from a gut standpoint, this stuff is for you. It's also wonderful for muscle building, it's wonderful for the immune system. And we are offering this at 20% off right now at getkion.com/bengreenfield. So, you just go to getK-I-O-N.com/bengreenfield. That'll automatically get you 20% off of the Kion Colostrum.

This podcast is also brought to you by my friends at Joovv. And I'm speaking about heat today, but if you want invisible heat, meaning, near-infrared and red light therapy in addition to things like infrared and dry heat, then you're going to get the best of all worlds from a collagen standpoint, from a wound, or a wrinkle, or a scar healing standpoint, from a thyroid boosting standpoint. This stuff has been shown to increase the level of testosterone and free testosterone in men. It's called Joovv. They designed these lights and they upgraded them recently to be 25% lighter, super intensified coverage areas. You can stand as much as three times farther away from them and still get the recommended dosage. It's way healthier than the bright blue light you get from all your screens. You can simulate sunrise with their ambient mode, which is like this calm, low-intensity mode I've been using at night in my office. You can simulate sunset so it's fantastic for sleep. They're going to give all of my listeners an exclusive discount on their Joovv lights. So, just go to J-O-O-V-V.com/ben and apply my code BEN to your qualifying order, and they'll give you the VIP treatment and exclusive discount. So, J-O-O-V-V.com/ben and use code BEN.

Alright. So, this podcast, remember, all the shownotes, and there's a bunch of them, are going to be at BenGreenfieldFitness.com/hotandcold. Sit back, get ready to take notes. Here we go.

Welcome to fire and ice, the benefits and science of hyper and hypothermia. But honestly, fire and ice sounds way cooler. So, let's try and use that vernacular whenever we can, just so we're not too geeky. I love heat. I love cold. I've found a lot of benefits from them. I've studied up on both of them. And so, I'm going to fill you in on all of the ways that both heat and cold can make your life better. I'm going to fill you in on some cool biohacks and techniques that you can use to enhance the effects of heat and enhance the effects of cold. I feel as though there's not really one single place where a lot of this information lives when it comes to comprehensive science-based treaties of what happens when you're hot, what happens when you're cold, but then also kind of the practical manifestations of what to do once you're armed with this knowledge. So, that is what we're going to delve into today. It's going to be fun. So, strap on your thinking caps and prepare for a wild ride.

Alright. A little bit about me. I am often asked about my sexy wounded healer story and how I got into all of this in the first place. Fact is I've always loved physical culture, fitness, the outdoors. I grew up in North Idaho playing tennis, and hiking, and chasing rattlesnakes, and making fortresses out of rocks outside, and playing with my bow and arrow and dogs. I just absolutely have always loved just physical culture in general. And I was homeschooled and I also did geeky things like played violin and chess, and I was super into fantasy fiction. But I also spent a lot of time outdoors, just based on the nature of the fact of being homeschooled. I was usually done with school by like 11 or 12 and had the rest of the day to just play. My family wasn't super into video games and TVs. And so, I was pretty much outdoors or reading books most of my young life.

And that eventually led to playing a lot of tennis, playing high school tennis, and eventually playing college tennis. And I played a local community college for a couple of years, and then I wound up attending University of Idaho. And it was at University of Idaho where I studied exercise physiology and biomechanics, and wound up branching off to a lot of sports beyond tennis. I got into water polo and played whole set for the water polo team. I played middle for the men's volleyball team. I got into bodybuilding. I managed the local wellness facility and picked up a bunch of personal training certifications and nutrition certifications in addition to my course load at University of Idaho, which also included a full pre-med curriculum, even though I opted later not to attend medical school.

But ultimately, just to give you an idea of how geeked out I was, this is me in my bodybuilding days, and I actually was using a little bit of heat back then to strip off some water weight, and that was one of the techniques I got into was those long sauna sits somewhere a wrestler might do. Not that I consider some forms of that to be healthy, we'll get into some of this in the presentation, but I body build, and that's kind of like the original geeked out, almost like an underground biohacking sector from the '80s, people injecting all sorts of different substances and taking all sorts of crazy synthetics. I was dirt poor as a college student and I pretty much did all my bodybuilding via sweat, blood, tears, creatine, and some really nasty tasting protein shakes and a ton of caffeine before I'd work out. That was my stack because that's all I could really do in college.

And then, from there, I proceeded into the next most unhealthy sport of the planet, arguably, Ironman triathlon where I competed for about–anywhere from–I think it was about 10 to 12 years in races all over the world. And kind of like bodybuilding, I actually learned a lot, especially in triathlon with heat acclimation, with cold acclimation. I did tons of cold water swimming, tons of sauna training, three to four-hour bike rides in the sauna where I just punish anywhere from 40 to 60 ounces of water an hour. I was losing fluids so much. And we would have sweat sodium analysis done for team Timex when I raced for them. And so, I learned a lot about sodium balance, and electrolyte balance, and heat.

And then, of course, as far as the cold goes, I didn't realize at the time that I was getting all the benefits of cold thermogenesis, but I mean, I was literally cold almost every single day, whether it was a 5:00 a.m. pool session where I was freezing in my speedo going back and forth in the fall, in the winter when all the drafts are coming in through the gym pool, or whether I was out on a crisp spring morning or a fall morning in April or September in an icy cold river, or lake, or ocean. Sometimes in a wetsuit, but still pretty darn cold. I remember my longest cold water swim was upriver in the Spokane River in–it was about mid-April, and I was so cold, shivering so badly, face entirely blue. I literally crapped my wetsuit trying to get up to my car and nearly passed out. I do not recommend that approach to cold thermogenesis, but that was my initial introduction to that.

So, what we're going to do in today's presentation is we're going to start with fire, with a good, old sauna and heat, and what we can learn about heat. Now, what's interesting is that even though we're not going to focus on many of the medical aspects today, probably, even though I've done all those bike rides and the saunas from my Ironman triathlon days in preparation for races like Ironman Hawaii, for example, and even though I did a lot of long sauna sits during my bodybuilding days, the most uncomfortable I've ever been was when I got curious about the cancer treatment hyperthermia. This is often used in European biological medicine. It's increasing in popularity in the U.S., and there's lots of compelling research behind the cytotoxicity of hyperthermia, kind of based on the same concept of your body presenting a certain amount of toxicity to foreign invaders when it induces a fever, for example, which is why sometimes taking like an antipyretic medication or something to shut down a fever is not the best idea when you're sick. You want your body to get hot to get rid of some of the pathogens to a certain extent, if your fever is up above 104. So, you probably want to begin to manage that so you don't kill off brain cells.

But speaking of killing off brain cells, this hyperthermia chamber that's often used for cancer treatments is just this large claustrophobic chamber in which your head's sticking out. My experience was one which I was lying flat on my back inside a pod, again on my back inside a pod laying down. This was at the Swiss Medical Clinic in Switzerland, of all places. And what they did was they put me in this really hot room, had me ride a bike extremely hard for 30 minutes. I got my heart rate just through the roof. I was already dripping in sweat. Then they took me into this other room, stuck a rectal probe up my butt, put me in this hypothermia chamber. And I believe the goal that they were getting to for internal temperature was somewhere right around in the range of 103, 104. They're basically inducing a fever.

And I wasn't doing this because I had cancer. I was doing it as a form of immersive journalism. I wanted to see what this felt like, what true hypothermia involved, and it was the most uncomfortable thing, not the most, but one of the most uncomfortable things I have ever done. My wife would say that her childbirth was far more uncomfortable, and so I won't deny that there are less comfortable things than a hyperthermia treatment. But I was in there for about three hours. Common treatment is anywhere from three to four hours. And I had a little screen in front of me that was supposed to play DVDs, but that was broken. So, I was just staring at the white ceiling. And a nurse was there. She would dip my forehead with an icy cold towel about every five minutes to keep my brain from getting damaged by the heat. She had a little sippy straw, and she would hold water up to my mouth again about every five minutes for me to sip. And I just sat there and watched the reading from the digital rectal probe, show my temperature climbing and climbing and climbing, well above 100 degrees. And at the same time, I watched my heart rate going up and up and up, just laying there on my back. My heart rate got up to about 140, just based on the fact that my heart was trying to cool my body.

And finally, they let me out. I tapped out. I got to a certain point where I was like, “This is the hottest, most claustrophobic, most uncomfortable that I think I've ever been.” And I could imagine that if I had cancer, I would be motivated to do something like that on a regular basis. But in this case, my motivation waned and I tapped out, but I definitely got the full meal deal sensation. I was about to go take a cold shower afterwards, but they told me that the way this works is with that fever-induced, you then go lay in your bed for about five hours and just basically pass out, dripping with sweat, completely hot. So, that's what I did, went upstairs to my bedroom in the–it was actually a heat wave in Europe. And so, it was about 102 degrees in my room there at the Swiss Mountain Clinic, and I just basically passed out for about four or five hours. Woke up, felt kind of woozy, dragged a bunch of water, finally took a cold shower. I definitely felt cleaned out/exhausted from the experience.

So, do you need to do all that to enjoy the benefits of heat? Not necessarily, but there are some cool things you can do. So, let's get into that. And if you hear a little buzzing in the background, it's because I'm walking on my treadmill while I'm giving you this presentation, getting my step count in.

Speaking of step count, let's begin with the endurance benefits of heat. So, this has been pretty well-studied. It's probably, like I mentioned, the initial way that I got interested in heat in general aside from some of those bodybuilding sessions that I had done. So, we know that it can lower your resting heart rate directly by increasing your blood volume, which is why a lot of endurance athletes like to do sauna sessions because you get a similar effect as you would with using the illegal performance-enhancing drug erythropoietin in terms of the increase in red blood cell count and the increase in plasma volume. They've actually shown, compared to a control group, a 30 plus percent increase in running endurance when running is accompanied by a 30-minute sauna session that takes place two times a week for three solid weeks post-workout in runners.

So, runners who regularly hit the sauna for 30 minutes after a hard run, which is actually kind of hard to do because your body's already hot, you see a drastic improvement in red blood cell count, in plasma volume, and most importantly, in actual performance gains based on that. So, the body just tries to compensate for the rise in plasma volume by making more erythropoietin. So, when you're not in the heat, you're delivering a lot more oxygen to cells. Now, this type of hyperthermic conditioning can also optimize blood flow to the heart, to the skeletal muscles, to the skin because it increases the plasma volume. And that's also important because it allows you to lower your core body temperature if you are exercising in the heat. It also means that when you're not in the heat, you get reduced cardiovascular strain, you lower the heart rate for any given workload. And again, this doesn't mean that you're actually exercising in the sauna. You can literally just go get in the sauna after an exercise session to get this type of effect.

Now interestingly, you also see increased blood flow to the skeletal muscles to keep them fueled with glucose, and fatty acids, and oxygen. And this is important because what that means is you're able to reduce your dependence on glycogen stores. It causes you–it has this what's called a glycogen sparing effect. It allows your body to more efficiently hold on to carbohydrates during exercise, burn more fats as a fuel during exercise. And what they've shown in studies with hyperthermic conditioning in human athletes is that muscle glycogen usage is reduced by about 40% to 50% compared to before heat acclimation. And that's presumably due to the increased blood flow and glucose delivery to the muscles.

A couple other things that are really cool about what heat does specifically for endurance and cardiovascular performance is it improves what's called thermoregulatory control. Now, that's an activation of the sympathetic nervous system to increase blood flow to the skin, and thus, increase the sweat rate, which dissipates some of the core body heat. And so, after you've acclimated like that, what happens is that at any given temperature, you start to sweat at a lower body temperature, and your sweat rate is maintained for a longer period of time, so your body becomes more efficient at cooling itself, whether you're in or out of the sauna. And then, the other interesting thing is that they see that you tend to produce, or at least accumulate less lactic acid in the muscles when you're involved in a regular sauna practice, which again is going to make you a better exerciser in just about any sport that involves any amount of glycolysis, or burning of carbohydrate, or generation of lactic acid. So, extremely impressive in terms of what happens to your endurance capacity when you're doing something like sauna training.

I also want to focus on some other benefits. So, let's talk about the muscular benefits. One of the cool things when it comes to muscular benefits is you get increased muscle hypertrophy. Heat is known to induce muscle hypertrophy. So, muscle hypertrophy is an increase in the size of your muscle cells, and it usually is accompanied by an increase in strength of course. Now, skeletal muscle cells, those contain stem cells that can increase the number of your muscle cells. But hypertrophy generally involves an increase in size rather than number. And so, what you see in the heat is a shift in the protein synthesis to degradation ratio, which means you degrade muscles, specifically muscle proteins, less readily and synthesize them more readily.

So, your muscles always perform this balancing act between new protein synthesis and degradation of existing proteins. And what happens is the heat acclimation reduces the amount of protein degradation and increases net protein synthesis and muscle hypertrophy, and that can even occur if you're not doing, let's say like a strength training session or exercising in the sauna, which means that it's actually really useful for people who want to maintain muscle if they can't lift weights. So, you're injured and you can't lift weights. I have a lot of my clients go hit the sauna when they're rehabbing an injury just because it allows them to maintain some of their muscle.

Now, the muscle hypertrophy in addition to increasing net protein synthesis causing that, you also get induction of heat shock proteins, you get an induction of growth hormone, you get increased insulin sensitivity, so the muscles are pulling in nutrients more readily, and you delay muscle atrophy. And so, all of these mechanisms are really cool because not only are they going to increase muscle hypertrophy and muscle protein synthesis, but the other thing that happens is the mitochondria kick into gear to help meet the increased energetic demands of the muscle cells when you're in the heat, to produce new energy in the form of ATP. It's called oxidative phosphorylation. And what that does is it kicks off some free radicals like superoxide and hydrogen peroxide. It creates oxidative stress, and you'd think that'd be a bad thing. But what happens is when that happens, your body induces what's called HSP.

And so, HSP induction in response to all these free radicals to mop up the damage, it prevents the damage by scavenging the free radicals and by increasing cellular antioxidant capacity, primarily by maintaining glutathione status, it repairs misfolded and damaged proteins. And so, it essentially increases your overall cellular resilience as a, what would be known as a hormetic stressor. You get the heat as the hormetic stressor, it produces the free radicals, the HSPs, prevent the damage, but then because you have an increased production of the HSPs, your muscles can build faster, your mitochondria can proliferate more readily, and you're essentially inducing cellular resilience via the regular exposure to the heat. So, it's really kind of a cool effect.

Now, of course the other thing that I mentioned was the growth hormone benefits. And what you see in response to regular heat practice is a pretty massive release of growth hormone, and that that can have a really great anabolic effect mediated by IGF-1. So, IGF-1, insulin-like growth factor 1, is synthesized and responds to that growth hormone. And there's two cool things that happen when you produce your IGF-1. You activate the mTOR pathway, which is responsible for protein synthesis. And then, the other thing that you do is you inhibit what's called FOXO activation, which can inhibit protein degradation. So, for example, mice that the engineer to express really high levels of IGF-1 in their muscle, develop some really significant skeletal muscle hypertrophy, they combat age-related muscle atrophy, and they retain the same regenerative capacity as young muscles. So, regular heat practice essentially allows you to build and maintain young muscle even if you're aging, which I think is really cool.

And they've actually administered growth hormone, for example, in human endurance athletes for about four weeks, and they've shown that muscle protein oxidation, which is a biomarker for protein degradation, it decreases by about 50%. So, literally, people who want growth hormone for that anti-aging effect, that growth hormone is so popularly known for, you can actually get it with as little as a couple of 20 to 30-minute sauna sessions in a single week. I'm a bigger fan based on some of the finished longevity studies of trying to hit the sauna closer to four to five times a week, but it's impressive, nonetheless, the increase in growth hormone activation.

The other very cool thing is the increase in insulin sensitivity. Now, the increased insulin sensitivity, the reason for that is insulin is this endocrine hormone. It regulates glucose homeostasis, it promotes the uptake of glucose into muscle tissue and into adipose tissue, and it also plays a role in protein metabolism. It regulates protein metabolism by increasing protein synthesis, because you're up taking more amino acids into skeletal muscle when they're insulin sensitive, and then it decreases protein degradation through inhibition, what's called a proteasome, and that's a protein complex inside your cells that's responsible for the degradation of cellular proteins. And so, when you, for example, do an insulin infusion in healthy humans, and you increase insulin levels, what that does is it suppresses muscle protein breakdown without significantly affecting muscle protein synthesis.

And so, hyperthermic conditioning or irregular sauna lends itself to muscle growth, not only through those growth hormone and heat shock protein pathways, but through a promotion of insulin sensitivity, which decreases muscle protein catabolism. And they've even shown in insulin-resistant diabetic mice that they see a significant re-sensitivation in insulin and reduction in blood glucose levels indicating that it's actually really metabolically healthy to engage in sauna use pretty readily. You also see an expression or an increased expression of something called GLUT4. That's responsible for transporting glucose into skeletal muscle from the bloodstream. And decreased glucose uptake, that's one of the mechanisms that leads to insulin resistance. But what happens with the upregulation of that GLUT4, which you also get in things like strength training or even cold thermogenesis, which we'll talk about, it's one of the best ways to make yourself metabolically healthy, which is again probably one of the reasons we see in these finished longevity studies people living, men particularly, a significantly longer period of time when they have a regular sauna practice.

Now, like I briefly alluded to, for people who are injured, this is really great, it's really great, because muscle atrophy is going to occur when we tip the balance toward protein degradation and away from protein synthesis, and that happens during immobilization, it happens during disuse of a muscle. And so, you want to somehow maintain a hypertrophic state of the muscle that's injured. Unfortunately, loading the muscle to allow that kind of muscle regrowth or muscle maintenance can be difficult if you're injured. But when you look at the effects of whole body hyperthermia on preventing the muscle atrophy and increasing the muscle regrowth, even after immobilization, which they've shown in studies, that elevated HSP basically is the mechanism via which you hold on to muscle as you are injured. So, again, it's wonderful if you're injured and if you can't get out and exercise to scratch that itch instead by getting in the sauna. And it's cool because psychologically, you know that your body is still getting better. And then, physically, you're actually maintaining that muscle that's not being used.

So, I've alluded a couple times to the longevity benefits of the sauna, and this is one that's been well. So, a lot of people know this. So, in flies and worms, just a brief exposure to heat treatment has been shown to increase their lifespan by up to 15%. And that's mediated by these heat shock proteins. That hormetic response that increases the heat shock proteins is associated with longevity. And it's just basically decreasing the rate which telomeres shorten and is protecting DNA, cellular membranes, and mitochondria, when you have this regular sauna practice. That's something that's been known for a while. Rhonda Patrick has talked a lot about those finished longevity studies. And that's of course just kind of a gimmie when it comes to anti-aging tactics.

Now, the brain has also really, really helped dramatically by regular sauna or heat exposure. So, this again partially comes down to the heat shock protein production. So, what we know is that when you get in a sauna, sauna-induced hypothermia can induce this robust activation of the sympathetic nervous system and the HPA axis. So, your hypothalamic pituitary adrenal access is actually going to overdrive a little bit because the sauna is mildly stressful. That's why a lot of times if you're in the sauna, you see an increase in norepinephrine, you see an increase in blood flow or blood glucose, you see a big increase in prolactin, you see an increase in cortisol. But then when you get out of the sauna, all that stuff drops. It's like when you exercise–well, if you exercise for a really long time, you're just going to constantly have a really high heart rate, and really high cortisol, and a lot of muscle damage. But then, brief bouts of exercise are actually really good for you.

And it turns out that the same thing can be said for the sauna. And the reason for this is that big surge in prolactin, that promotes myelin growth. It makes your brain function faster, and that's a key in repairing nerve cell damage. Then you get the increase in norepinephrine, which allows you to better handle stress. That's why a lot of people feel stressed out. If they get in, they do a sauna session [00:28:47] _____ Zen afterwards, especially if you do it regularly, because your body is getting used to having to deal with this norepinephrine response, and begins to blunt a hefty norepinephrine response when you're stressed out by, say, emails, traffic, arguments, et cetera. And so, it stresses you out short-term the sauna does. But then when you get out, you're actually de-stressed.

Now, we know that heat stress can also increase the expression of brain-derived neurotrophic factor, and that's BDNF. It increases the growth of new brain cells. It's the reason people take things like lion's mane, and smart drugs, and nootropics, but heat is one of the best ways. Heat and aerobic exercise can both pretty significantly increase BDNF, the fact that I think my assistant turned the heat on in our house. I usually keep our house pretty cold for some of the cold benefit, but I'm walking on the treadmill and I'm actually sweating while I'm talking to you guys right now. So, I'm increasing BDNF via both heat that I'm generating by walking, and I'm also increasing BDNF based on the fact that I'm aerobically moving as I'm talking to you.

So, BDNF can also ameliorate depression. It can increase resilience to stress in a similar manner as those norepinephrine pathways that I talked about earlier. And a beta-endorphin, which is induced by hyperthermia, is actually one of the things that has this feel-good effect when you get out of the sauna. So, that's another cool effect of it. But in addition to this beta-endorphin, the other one that you should know about is dynorphin. So, dynorphin is what's responsible for your runner's high. Okay. So, beta-endorphins are these endogenous opioids. They're natural opioids that are part of your body's natural painkiller system. It's called the mu-opioid system. And you can block pain messages from spreading from the body to the brain via this process called antinociception when you have high levels of these natural painkillers circulating in your body.

Well, there's this peptide that's a little bit lesser known. It's called dynorphin. It's called a kappa opioid, and that's responsible for the sensation of painkilling. You get it when you eat spicy food, you get it when you're doing intense exercise afterwards. That's why you feel good after a high-intensity training interval session. And then, you also get it from the sauna. And so, that's why you almost feel like you have kind of like a feel-good, mood-enhancing runner's high effect when you're in the sauna. It's also why sometimes if you get into a sauna, it feels uncomfortable for the first 10 minutes. And then, as your body produces more and more dynorphin, you can last a longer period of time in the sauna.

The other cool thing is that the dynorphin, these new receptor agonists, they can induce increases in body temperature. And so, what happens is that they appear to have some type of temperature-regulating effect, which is all just really cool because once again, coming back to the cardiovascular and the endurance benefits, it means that if you're out exercising the heat and you're a regular sauna visitor, exercising on the heat is going to feel way easier. I mean, any exercise that's intense, because your body heat's going to go up anyways, is going to feel way easier. So, that dynorphin is kind of a fantastic bonus of the regular sauna.

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I want to give you a few quick tips and tricks to enhance your sauna experience because there's certain things that have actually been shown to cause your sauna to be a little bit more effective. So, the first is this idea of topical muscle warming creams. These are called embrocation creams. I remember I first discovered these when I was racing triathlon, and I had some triathlons in really cold weather, and somebody told me about this cream that cyclists put on their muscles to help their muscles feel warm. Usually, it has stuff like capsaicin and other topical ingredients that bring blood flow to the surface of the skin. And I remember I used this capsaicin one, but I used it as I was getting ready for the race. And then, as you do right before the race starts, I [00:36:11] _____ to go to the bathroom before the race. I still have this stuff on my hands, and I wipe my butt, and all I remember is just me having one of the best swims of my life in that race. I swam like hell, and it's because it felt like red ants were eating my balls off. And so, there's another bonus. If you want to run faster, just smear this topical muscle warming cream everywhere, fellas.

One that I like was made by a company called ATP Science called Prototype 8. I think they discontinued that. It was an Australian company, but you can go to Amazon, for example, and type in embrocation cream. That's E-M-B-R-O-C-A-T-I-O-N, or topical capsaicin, but a few other things you can do, black pepper tea. Black Pepper can actually heat the body from the inside out. The piperine in it can increase your body temperature. And so, before sauna session, you can literally just have a cup of hot water and you can put a few grinds from your black pepper grinder, a few shakes from black pepper in there, and that's another really great way to heat the body from the inside out, niacin, and even things like Viagra and sildenafil, and these blood flow increasers.

People who are doing sauna for the detox effect may be interested in this because nicotinic acid, niacin or niacinamide, for example, it causes this kind of flushing effect that increases blood flow to the liver and to the kidneys. That's why a lot of times, high-dose niacin is used therapeutically to inhibit your free fatty acid release and to decrease LDL, and increase HDL. But niacin can also really enhance these detox pathways because it inhibits oxidation in the vasculature. And so, basically, what this means is that your liver and your kidneys are just going to flush toxins through a little bit more quickly when you get a really good blood flow opener into your system, like niacin. Now, you can bind those toxins as they wind up in the gut and in the bloodstream by also consuming activated charcoal. And a lot of functional medicine practitioners for folks who are detoxing, folks who have like mold, mycotoxins, stealth infections, things like that, one of the protocols they'll recommend, and this is one I'll do even on like a weekly basis for one of my sauna sessions, is you have a big glass of activated charcoal drink before you go get in the sauna. And so, if you do that, and then you've already taken niacin about 30 to 60 minutes prior, you get the blood flow, you get the flush, you can do the black pepper tea and the topical muscle warming cream to enhance that even more. And then, the charcoal binds it, so it gets removed more readily in your stool and–well, primarily, with charcoal, it's going to be in your stool. So, you might have a nice, big, black poop at some point after your sauna session.

Now, a few other cool ways to enhance the effects of the sauna. One would be the use of this halotherapy. And I have a Clearlight infrared sauna, this one called a Sanctuary. It's this big sauna. I can fit like four to six people in there for a dinner party because we like to do a lot of hot/cold dinner parties at our house. But I can also basically just get in that sauna myself and do yoga, swing kettlebells. I can put a bike in there if I'm a glutton for punishment, et cetera. But this company Clearlight, they also sell these halotherapy units that you can install in your sauna. And it's basically salt therapy. The efficacy of salt for improving respiratory issues is something that's been done for a long time. It's practiced in ancient Greece and Rome, and medieval Europe in the 1800s. There was this researcher who noted a huge amount of respiratory health benefits, and in minors, who are working in salt mines in Poland, really low occurrence of respiratory problems in these folks.

And so, the way that Halotherapy works is this little unit, and you can put it on the wall of your sauna, or the floor of your sauna, you dump some salt in there. There's a little aluminum ball that rotates, and it tears apart the salt and releases these microscopic particles like micro-crystallized salt into the air, and you breathe this in. And not only do you breathe it in, but you sweat more while you're in there. And so, that's another thing that I always run in my sauna now when I get in the sauna. And you just feel better, you breathe better, you sweat more. Essential oils, huge fan of those. Usually, I'll do some real warming essential oils in there. I like peppermint essential oil. Cinnamon is good, but you got to dilute it because it can burn the skin a bit. A tobacco essential oil is another great one.

There's a physician in Sarasota, Florida, who makes this Amazonian spray, it's based on an alkaloid from the Amazon called Rapé, and he has like an intranasal administration of that. I interviewed on my podcast Dr. John Lieurance. If you go to BenGreenfieldFitness.com and search for his Zen spray, you'll find that interview. And a few sprays of that has a similar effect as the black pepper tea. And the one-two combo will really get you hot for your sauna session. I'm often asked about re-mineralizing afterwards. My go-to is Quinton. It's a hypertonic plasma solution. I get it from either Water and Wellness or Quicksilver Scientific. But they take seawater. They use this cold microfiltration on it. It has like 78 minerals and trace elements in it. It's one of the best kind of like electrolyte rehydration type of things that I've ever used. And it's all the more important if you're doing some of these binders like charcoal or blood flow increases like niacin. But this Quinton hypertonic plasma, I usually do a shot or two of that after the sauna. If you don't have that, just make sure when you're drinking water for all the water you drink after your sauna sessions on your sauna days, use a really good salt. Celtic salt is pretty high in minerals, pretty low in things like microplastics and metals, so that's another option if you didn't want to get the Quinton, which actually is a little bit expensive.

Now, you'll note, I say, to be a little bit careful with neuromuscular recovery time. So, here's what I mean by that. As you've learned, the sympathetic nervous system gets put through the ringer when you're doing a sauna session. And so, because of that, you should ideally track your heart rate variability if you can, if you have like an Oura ring, or a WHOOP, or anything that will track your HRV because sometimes people will do a sauna every day and it's just so stressful for their system that their HRV never bounces back. So, I'll often glance at my HRV in the morning. And if it's lower than typical, I'll often not do a hefty sauna session just because I know what happens from a sympathetic nervous system standpoint. So, remember, even if you're not getting sore after your sauna sessions, you do want to make sure you're not overstressing your nervous system. And frankly, I've found with a good amount of hydration and electrolyte intake, my HRV bounces back way faster after a sauna session. So, those are the basics when it comes to the heat.

And now, we are going to move on to, you guessed it, ice. So, ice, I already told you about how I first discovered how intense cold thermogenesis can actually be during my early days of cold water swimming back when I was racing triathlons. But really, it was a while between the time that I was swimming upstream in that icy Spokane River, and I really began to look into the benefits of actual cold thermogenesis and what it can do for the body. And trust me, you do not have to swim upstream in an icy cold river, or really even get an ice bath regularly to get a lot of the benefits of the cold. So, with the cold, we're actually going to start with the brain because the effects of cold on the brain I think are often not talked about enough because–one of the most consistent and profound physiological responses to cold exposure, especially if your head is under the water–and this is actually probably why they've found in a recent study just last week a decrease in the risk of depression, dementia, and Alzheimer's in people who regularly swim in cold water.

And part of that is related to this release of norepinephrine into the bloodstream. It winds up in what's called the locus coeruleus, region of the brain. And it's very interesting because this norepinephrine is a hormone and a neurotransmitter involved in things like vigilance, and focus, and attention, and mood. So, the cold induces this robust increase in norepinephrine mediated by a sympathetic nervous system, fight-or-flight response. And what happens is that increased neurotransmission and the effective metabolism norepinephrine, it actually combats things like ADHD and depression. And the reason for that is norepinephrine is depleted in people, typically by pharmacological interventions, and that can cause depression, a lot of people who are using what are called norepinephrine reuptake inhibitors. And the complete opposite happens when you get regular cold exposure.

Now, you also get an acute increase in vasoconstriction and constriction of blood flow to the brain. But after that happens, you get this big rush in blood flow to the brain. And so, what happens as a result of that increase in norepinephrine neurotransmission is this increase in focus, and cognitive ability, and energy, and mood. And this all happens as soon as you get out of the cold and begin to warm up. But the effects don't stop there when it comes to the brain. And just so you guys know, a cold-water immersion at about 68 degrees Fahrenheit, which is not that cold, one hour at 57 degrees Fahrenheit increases norepinephrine by 500% and dopamine by 250%, 40 degrees Fahrenheit cold-water immersion for about 20 seconds, 20 seconds increases norepinephrine 200% to 300%. So, you can see like 20 seconds versus an hour at a slightly warmer temperature dictates that just a few quick dips in an ice tub versus spending an hour at 57 degrees Fahrenheit actually still gives you a significant increase in the norepinephrine and the dopamine response.

Now, the important thing about norepinephrine is it also has these really profound effects on pain, and metabolism, and inflammation, and it can even maintain some amount of serotonin balance. So, there's some really cool things happening with this big increase in norepinephrine. Now, the synapses between your neurons actually do break down during cold exposure. And you'd think that that would be bad, but what happens is animals that hibernate when they warm back up, they regenerate these synapses. And so, based on this, researchers actually looked at mice who had cold air exposure about 41 degrees Fahrenheit for around 45 minutes, and they actually got about a 25% loss of synapses in their hippocampus. But once they warm them back up, they rapidly regenerated those synapses.

And the mechanism by which that occurred was dependent on this thing called RBM3. That's a cold shock protein. Okay. So, you already know what a heat shock protein is. That's a cold shock protein, that's RBM3. And just like the mice, we also have that. And that's what is responsible for allowing for the restoration of synapses. It binds to RNA. It increases protein synthesis at your dendrites, which are part of the neuron that communicate with the synapses, and it regenerates those damaged neurons. And this is really cool because when we're constantly bombarded by brain inflammation, Wi-Fi, and 5G, and cell phones, all these synapses, they do get a little bit of damage done to them. But it appears that cold is actually able to regenerate that to a certain extent. And some neurosurgeons will actually utilize cold in their practice as a way to not only keep the blood-brain barrier integrity and decrease inflammation, but also increase the repair of these synapses.

Now, the ability to prevent the loss of synapses, that's pretty significant because losing synapses is something that occurs in neurodegenerative diseases like Alzheimer's, and Parkinson's disease, and even after traumatic brain injury, which is why regular cold exposure, if you had a TBI or concussion, is something that's actually smart to do. So, a few other things regarding this RBM3 is the cold water immersion for something like that. It's a little bit longer. You can see that 41 degrees Fahrenheit for 45 minutes for mice, but that's ambient temperature, that's not cold water immersion. And so, that would be like a long walk outside in the cold for 45 minutes to an hour, which is not that bad. And then, if you can get a 2 degrees Fahrenheit reduction in core body temperature, that can induce this RBM3 cold shock protein, and that's about 57 to 68 degrees Fahrenheit.

So, again, you can either do these brief super cold ice soaks. Like most of the data, it's anywhere from 20 seconds, like I mentioned, up to a maximum about 10 minutes that you would need something like cryotherapy or the intense ice bath immersion. Those can be a lot shorter. But you can also get similar effects with a long swim at your local gym that keeps the pool cold, or just going to a lake, and dipping in the lake, and just hanging out in the lake for a while, or just, I do a lot of this, just in the winter or the fall, go for a walk without many clothes on, and you can get a lot of these same effects. You don't have to just like freeze your eyeballs out in an ice tub every day. There's a lot of ways to do this. So, brief bouts of really cold or longer bouts of kind of cold both seem to have a pretty good effect.

Now, the cool thing about cold is it affects a lot of stuff within the brain. So, there's some inflammation and immune system benefits. So, we know that the norepinephrine that's released during the cold, that can inhibit a lot of inflammatory pathways. It decreases what's called TNF-alpha and macrophyllaes inflammation. So, the reason you have inflammation is it eliminates the initial cause of a cell injury, clears out dead cells and tissues that get damaged from an insult, and the inflammatory process can initiate tissue repair. When that process runs awry, like in the absence of a biological threat, and instead because of just chronic stress, it's a pretty key driver of the aging process, and it's actually associated with a lot of age-related diseases. Low inflammation is the only biomarker that predicts survival and cognitive capabilities across all age groups when you look at centenarians, and semi-supercentenarians, and supercentenarians. Like, it's pretty much low inflammation. That's the main thing.

Now, norepinephrine reduces inflammation. And so, we know that norepinephrine is really cool as a neurotransmitter, but it also inhibits this tumor necrosis factor-alpha, the TNF-alpha, and that's a potent molecule that increases inflammation. But then it also is something that decreases macrophage inflammatory protein, MIP-1, and that's produced by immune cells and can cause things like arthritis and other inflammatory-related conditions. So, this also might be why a guy like Wim Hof can get a really robust immune system response and was shown to be able to fight off toxins. I believe in this case it was an E. coli injection that he had just based off of his regular heat practice.

Now, there's some other cool things though when it comes to the inflammation and the immune system. Some of these pro-inflammatory molecules that I told you about, like TNF-alpha and some of these prostaglandins that get produced in response to inflammation, those can cross the blood-brain barrier and they can activate some of the brain's immune cells that are known as microglia. And what happens is that when you increase norepinephrine, that doesn't occur to as great an extent. I suspect part of it, too, is because cold can improve the integrity of the blood-brain barrier, and it also increases the activity of a lot of antioxidant enzymes, very similar to the way the heat does it. But in the case of cold, what happens is that it's shutting down a lot of the reactive oxygen species, and that's because of a doubling of one of your body's most potent antioxidant enzyme systems called glutathione reductase.

And there's another one called superoxide dismutase. That also gets just through the roof in response to cold. So, all of that is really fantastic for inflammation and the immune system. But then the other interesting thing is that cryotherapy, even local cryotherapy with those little cold wands that you'll find a lot of health clubs or medical treatment facilities these days, that inhibits what's called collagenase activity, which as the name implies is something that breaks down collagen. Now, in addition to decreasing the production of prostaglandins, which can have an effect on breaking down collagen, cold can decrease pain response to an injury, but then also decrease the amount of collagen that breaks down. So, this is why, as you can imagine, like a one-two combination of a regular heat practice and a regular cold practice is fantastic for a variety of benefits, but it's really impressive in terms of the ability to be able to manage injuries, or even allow injuries to heal a little bit faster.

We know that aging is something that can cause the production of immunosenescence. So, you basically get these non-functional immune cells. And what cold can do, and this was a case in which they did long-term cold water immersion about three times a week for six weeks in males, it increased lymphocyte numbers, and that's a type of white blood cell. And when you increase those white blood cell numbers, you're getting an increase in the amount of cytotoxic T lymphocytes. And those are a special type of immune cell that can kill cancer cells. And these natural T killer cells would decrease naturally with age, which is why I regularly consume things like thymus extract and sweet breads, and even use peptides like thymosin alpha-1, for example. But you can also increase the cytotoxic T lymphocytes with regular long-term cold exposure. So, that's another really, really cool benefit when it comes to inflammation and the immune system. So, there's some really cool things going on in terms of you staying healthier and you being able to fight off inflammation more readily.

Now, of course cold is well-known for its effects on the activation of this uncoupling protein. Okay. So, I'll explain to you what this means and why this is important for fat loss. So, basically, there's two different types of thermogenesis that occur when you get exposed to cold. So, first, you'll ramp up your metabolism, like your metabolic rate will increase to produce heat. And as part of that, your body also burns through glucose, just like freaking candy, pun intended. I found one of the best ways when I'm using a continuous blood glucose monitor, to control my blood glucose the entire day long is a good 5 to 10-minute cold exposure in the morning. It's fantastic. And part of that is the upregulation of metabolism. Part of it is the upregulation of some of the GLUT4 transporters, some of the increase in insulin sensitivity. But for blood glucose management, I mean, it's way up there for me as far as an effective tactic.

But in addition to the increase in metabolism, you also see what's called non-shivering thermogenesis. So, the increase in metabolism would be like you're shivering, your muscles are contracting, your metabolic rate is going up, your body's doing everything to keep warm. But then there's this thing that occurs on more of a cellular level, and that's regulated by the norepinephrine increase that I already discussed. So, when you have this cold induction of norepinephrine, you get an increase in the expression of this protein called uncoupling protein 1, UCP1. Now, that uncouples the mitochondria. What that means is that mitochondria would normally be responsible for generating energy by transporting electrons that are derived from food calories that you eat.

Now, cold exposure uncouples that electrochemical gradient. And what happens is that instead of producing ATP, the UCP effect allows the mitochondria to produce heat. And if you've heard of like white adipose tissue to brown adipose tissue are browning effect on fat tissue. One of the reasons for that is because of a higher amount of this dense uncoupling rich brown adipose tissue. And so, this BAT, this brown adipose tissue conversion, is something that can only assist with metabolism and heat production, but of course, it will decrease a lot of fat around the waistline, for example. You'll notice some big polar, bay area cold water swimmers, polar bear club members, sometimes they have some dense amount of fats up in their neck and the collarbone area, and that's because the browning of some of the white adipose tissue, some of the tissue can accumulate up there. But I mean, if you're doing other things to stay lean or watch your calorie intake, et cetera, you're not going to look fat up in your neck. You're instead just going to decrease the appearance of that white adipose tissue, for example, around your waistline or anywhere else. Along with that increase in metabolic rate and glucose response, there's a lot going on when it comes to maintaining your body composition or improving your body composition via this uncoupling protein and the white fat to brown fat conversion.

So, that's another wonderful effect. And there's a guy who runs this website. It's like coolfatburner.com. I interviewed him on my website. It's a podcast that was a few years back. But he even sells this cooling gear that you can wear at the office. And he's shown in his exercise physiology laboratory like a 300% increase in metabolic rate. When you just wear this clothing, they put a little bit of these ice packs that it comes with on your body. He's got one like a vest and one that just wraps around your waist. And he sees some really cool responses to fat loss, as have Ray Cronise. If you look up Ray Cronise in his Wired magazine article from way back in 2013, I mean, I remember he talked at a conference I attended, and he was seeing super impressive results without any changes in the diet, and people who he was simply having do a five-minute hot/cold contrast shower at the beginning and the end of the other day. It was 20 seconds of cold, 10 seconds of hot, 10 times through, and that's it. And that's an example of how little you need to get some of these benefits.

So, performance and recovery, there's a lot of benefits when it comes to cold and its effects on performance and recovery. For example, we know that right after exercise, you produce these pro-inflammatory cytokines, those activate immune cells, and they're involved in tissue repair. And these macrophages, I already talked about those, those are the type of immune cell that can get produced and activated in response to inflammation including, you guessed it, exercise-induced inflammation. Now, what happens is that when these macrophages, which are actually a type of immune cell, like I mentioned, get released, they can increase satellite cell migration. Satellite cells are basically like a stem cell, and they're associated with the same type of muscle hypertrophy that you get from strength training.

So, you exercise, you get inflammation. There's an anti-inflammatory response, and then these anabolic hormones get released. But what's more important to realize here is that a lot of people are under the impression that if you do hefty amounts of cryotherapy or cold that you're going to shut down that satellite cell migration, the mitochondrial proliferation, and the IGF-1 response that should occur in response to exercise because you're getting cold and you're decreasing the amount of some of these inflammatory molecules. If you actually dig into the research, you need a 3% to 8% drop in muscle temperature in order for that to occur. So, that's the equivalent of basically like 10 minutes of pretty cold water immersion. That's like doing a 10-minute ice bath. So, we're not talking about a cold shower, we're talking about 10-minute ice bath, and we're talking about doing that in like an acute post-exercise state.

So, yeah. If you're doing super-duper cold stuff right after you exercise, then you may actually see a blunting of the hypertrophic response, even though blunting is pretty slight. You see a small decrease in muscle mass, a small drop in performance. But again, that's acute exposure to really, really cold, like ice baths or cryotherapy chambers. Now, if you look at, for example, runners, 15 minutes of exposure to 50 degrees Fahrenheit, which is not super cold, following running can increase PGC-1alpha in muscle tissue, which is actually going to increase mitochondrial proliferation. Now, that's great for endurance athletes of course, and that's actually beneficial if you're endurance athlete.

So, I realize I'm getting into the weeds here, but what I want to do is step back and tell you that if you are an endurance athlete, a frequent runner, marathoner, triathlete, et cetera, after you finish a hard training session to decrease core temperature, get blood flow back to the gut faster, be able to sleep better at night, I've seen very little evidence that a post-long run or post-long bike ride cold exposure is going to impair endurance performance at all. And then, for strength and hypertrophy, the trick is allow your body time to produce that inflammatory response. Sure. If you're sweating and you're pitting out at the office after a strength training session, a quick cold shower to cool your body down, it's great. It's not going to blunt the hormetic response to exercise. A 10-minute ice bath, save that for at least two hours after the exercise session because it's about the two-hour window that allows your body to mount that inflammatory response.

So, it's about timing and dosing. And so, what I do is if I do an ice bath, like a long ice bath, like 10 minutes plus, I'm just not doing it right after a strength training session. And arguably, I'm fine with doing it after like a long run, or a long bike ride, or something like that. So, there's a few other considerations here when it comes to performance. For example, like I was mentioning on mitochondrial biogenesis, which is the production of a lot of these new mitochondria, the cold will activate this PGC1-alpha. That makes more mitochondria in the muscle. It's called mitochondrial biogenesis. And PGC1-alpha is the master regulator of that process. And if you get exposed to cold water after you engage in endurance exercise, we see an increase in that PGC1-alpha production.

And so, when it comes to triggering mitochondrial biogenesis, getting cold right after an endurance training session has a lot of benefits, again, unless your pure strength and pure hypertrophy. We also see, for example, in tennis players, doing cryotherapy after tennis practice, you get a decrease in TNF-alpha, you get an increase in some of the cytokines that can help to long-term blunt inflammation. And skeletal muscles in mice have been engineered to show increased levels of cold shock protein, that RBM3, and they've actually shown improved muscle cell survival and a larger muscle size after being exposed to the cold shock protein. So, what this means is that again, even if you're going after strength, after power, et cetera, cold is still going to be good for you, just don't do it right after your workout. Okay. So, hopefully, you guys are getting the idea in terms of timing, dosage, et cetera, when it comes to this cold shock protein, when it comes to decrease inflammation, et cetera.

What I do want to also do is get into some tips and tricks when it comes to cold thermogenesis. So, one, I already told you about. If you don't like to get wet, ladies, if you don't want to take a cold shower and lose all your makeup, and have to redo your hair, et cetera, this is a cool trick. Or guys, if you're at the office and you just don't want to duck out and take a cold shower, that equipment from coolfatburner.com is amazing. I have a lot of clients that will just wear that a few times during the day at work because it triggers the same type of brown fat thermogenesis, uncoupling protein, and metabolic activity as cold water immersion.

Melatonin is one supplement that's been shown to increase brown fat thermogenesis. So, best way to do that is just adequate sleep and paying attention to your light rhythms and your circadian rhythm. But you can also use small amounts of melatonin even pre-cold exposure. It's not something I do because melatonin makes me sleepy. I think some of these other things I'm going to give you are arguably better because of that, but just know that melatonin can increase some of the brown fat thermogenesis. Caffeine, cup of coffee, if you're going to be in the cold, preferably like an iced caffeine source would be better, so you're not having to re-cool what you've just heated up, that's another way that you can increase thermogenesis. There are things like bitter melon extract and a lot of the polyphenols that you'll find in oleuropein and kaempferol, those can also increase uncoupling protein.

One really cool study showed capsaicin from red pepper, piperine from black pepper, ginger, and cinnamon, can all boost thermogenesis. There's another supplement you'll find called Citrus aurantium. Okay. That has a noradrenaline effect, and also boost the activity of this uncoupling protein. Bile acids, which can directly upregulate your thyroid hormone function. So, taking care of your liver and your gallbladder health, but then also, considering the inclusion of like digestive enzyme supplements that have bile acids in them, that can also increase the thermogenesis in brown fat. Forskolin and another supplement, that activates what's called adenylyl cyclase in brown fat. So, you get higher amounts of cyclic AMP, and you get an increase in that metabolism even over and above what you get from pure cold.

One really cool study on fish oil, you saw an increased metabolism in mice and reduced fat accumulation by 15% to 20% by partnering fish oil with cold. And some people say, “Well, fish oil has calories and I'm getting [01:06:01] _____ to burn those first.” It's a drop in the bucket, folks, trust me. Same thing with ketones. Like, you can literally dose up with ketones, fish oil, a little bit of caffeine, and maybe throw in some of the polyphenols, and literally have like your own cold thermostack. As a matter of fact, if you listen to podcast number 420 at BenGreenfieldFitness.com/420, I have a whole stack that I get into that's my preferred stack. And I have links to all the different manufacturers, and the supplements, and the things that I pop before I do cold thermogenesis. And some of the newer research is actually on ketones, ketone esters, and the beta-hydroxybutyrates seem to really increase that white to brown fat conversion. So, kind of like with heat, there's also cool little hacks and supplements that you can use to enhance the effects of cold thermogenesis.

Now, a couple of other tips here. A lot of people struggle initially with the cold. And I think Wim Hof breathwork, don't do it underwater, don't do it while you're in the water, but doing like 30 to 40 rounds, and even two to three repeats of 30 to 40 rounds with a deep inhale, letting go, letting go, letting go, the Wim Hof style breathwork, deep inhale at the end, and then hold the exhale, that's basically like old school yogic fire breathing, it's inner fire, you're increasing your metabolism. And so, that's one way that you can, after you've done a session like that and you're not dizzy and can stand up, and you're not concerned about passing out, then you get in the water afterwards and it can really help you to maintain some of your nervous system resilience and your calmness in the water.

I'm also a big fan of box breathing. I learned this when I was doing some training down in Encinitas, I had this thing called Kokoro, which is kind of like Navy SEAL hell week for civilians. And they trained us to do a four-count in, four-count hold, four-count out, and four-count hold, when we were doing some of these frigid Pacific Ocean sits and doing like long ice baths like 15 to 20-minute ice baths. And that's what I teach my children to do, that's what I do myself, and it can really help with keeping you in the cold for a longer period of time if you really struggle with ice baths.

Another question I get is, what's the difference between these sexy, fancy three-minute treatments in a cryotherapy chamber versus cold water immersion? Well, I'm a bigger fan, actually, of cold water immersion rather than the cryotherapy. So, first of all, cryotherapy is a little less effective because it only uses air. So, ice has the greatest capacity to extract heat from the body, and then cold water is second, and air is third. So, you're basically getting less heat transfer out of the body when you're doing cryotherapy. So, that's one issue. And it's even a bigger issue if your head is not inside the cryotherapy unit, like some of these units are, because then you're not getting a lot of the mental effects, the brain effects I talked about when it comes to cryotherapy.

The other interesting thing is that with cold water immersion, you get this increase in the amount of surface area of the body that's exposed to the cold, and you also get this hydrostatic pressure of the water against the skin. And when that happens, you actually reduce a lot of the lymphatic fluid backflow that occurs in response to the cold that can actually have some of that inflammation-reducing effects that you might not be looking for if it's an immediate post-exercise scenario. So, that's interesting as well. It's a pretty similar increase in norepinephrine with cold water immersion versus whole body cryotherapy even though you got to do a longer treatment for the whole body cryotherapy. Again, 20 to 30 seconds in an ice bath versus three minutes in a cryotherapy chamber, that is arguably also more expensive.

And so, it's one of those things where I'm personally, if I can do cold-water immersion, like I have a cold bath called a Morozko Forge in my backyard. I got one of those above ground pools that I keep pretty cold. And then, I live like two miles from a river. So, whenever I can, I go with cold showers or cold water immersion. But the cryotherapy chambers, you're still going to see a good effect, but you just got to do them way more. They're less suffocation. So, I know they look cool, but they're just not as effective as cold water immersion, frankly. So, I'm not the biggest fan of them.

Geez, we made it. We made it through, you guys. So, if you get my book at boundlessbooks.com, I've also got tons more on cold thermogenesis in there as well. And if you reach out to me on social media, Instagram, Twitter, Facebook, et cetera, it's pretty easy to find my profiles there. I always like to help people, teach people, point people in the right direction. And hopefully, that wasn't just too geeked out and nerdy for you because I want to give you some of the practical things that I do as well. I'd probably behoove you to listen in that BenGreenfieldFitness.com/420, Podcast 420, where we really focus in on some of the things that can enhance the effects of cold. And that's it. So, thank you all. I hope you've learned a lot about fire and ice. I'm incredibly happy and blessed to be able to share some of what I've learned with you. This is what I love to do. So, thanks for tuning in, and I hope this has been helpful.

So, if you want to download the PDF, the slides for everything that you just heard, or if you want robust shownotes with all the studies, the extra resources, podcasts, books, goodies, everything, just go to BenGreenfieldFitness.com/hotandcold. I'll have it all there at BenGreenfieldFitness.com/hotandcold. Thanks for listening and have an amazing week.

Well, thanks for listening to today's show. You can grab all the shownotes, the resources, pretty much everything that I mentioned over at BenGreenfieldFitness.com, along with plenty of other goodies from me, including the highly helpful “Ben Recommends” page, which is a list of pretty much everything that I've ever recommended for hormone, sleep, digestion, fat loss, performance, and plenty more. Please, also, know that all the links, all the promo codes, that I mentioned during this and every episode, helped to make this podcast happen and to generate income that enables me to keep bringing you this content every single week. When you listen in, be sure to use the links in the shownotes, use the promo codes that I generate, because that helps to float this thing and keep it coming to you each and every week.



How do hot and cold therapies work?

Exactly how hot should your sauna be?

What are the benefits of dry vs. infrared saunas?

Is there anything you can use to heat up your body or enhance detoxification more during the use of heat?

How about how cold a cold shower or cold bath should be?

What kind of hacks increase fat loss in response to cold thermogenesis?

Does cryotherapy really “blunt the effects of exercise?”

In this extremely comprehensive overview of all things heat, hyperthermia, sauna, cold, cryotherapy, and cold thermogenesis, you'll discover everything you need to know about enhancing performance, cognition, fat loss, cellular resilience, detoxification, anti-aging, and much, much more. You can consider this podcast to be your ultimate resource on all things hot and cold therapy.

In this special “solosode” from Ben, you'll discover:

-How Ben got started using hot and cold therapy…6:25

  • Grew up in northern Idaho, where he was homeschooled
  • Spent lots of time outdoors and reading books as a child
  • Played tennis in college at the University of Idaho
  • Became interested in biomechanics and bodybuilding, managed wellness facility
  • Saunaused to help maintain weight as a bodybuilder
  • Sweat, blood, tears, creatine, protein shakes, caffeine– Ben's “stack” in college
  • Competed in Ironmans for 10-12 years
  • Used cold thermogenesisbefore fully understanding the benefits of it

-Ben's sadistic foray into hyperthermia…10:40

  • Hyperthermia is increasing in popularity for getting rid of disease, pathogens, etc.
  • Hyperthermia chamber used to treat cancer at the Swiss Mountain Clinic
    • Inducing a fever
    • Common treatment is ~3 hours
    • Ben eventually “tapped out” due to the level of discomfort
  • Article: Hyperthermia in Cancer Treatment

-The endurance benefits of heat…15:15

  • Lower resting heart rate by increasing blood volume
  • Saunasessions give a similar effect to the banned drug erythropoietin
  • Optimize blood flow to the heart, skin, etc.
  • Get in the sauna after an exercise session to get the effect
  • Glycogen-sparing effect:
    • Allows your body to more efficiently hold on to carbohydrates during exercise
    • Burn more fat as fuel during exercise
  • Studies (hereand here) in hyperthermic conditioning in athletes show that muscle glycogen usage is reduced by 40~50% compared to before heat acclimatization, due to increased blood flow and glucose delivery to the muscles
  • Improves thermoregulatory control (body is more efficient at cooling itself)
  • Less lactic acid in the muscles when involved in regular sauna practice
  • Article: Effect of post-exercise sauna bathing on the endurance performance of competitive male runners.

-Muscular benefits of heat…19:00

-Longevity benefits of heat…26:45

  • Brief exposure to heat treatment increases the lifespan of flies and worms by up to 15%
  • Hormetic response that increases heat shock proteins is associated with longevity
  • Protects DNA, inhibits telomere shortening

-How heat (or leaving heat) promotes brain health…27:35

-Tips and tricks to enhance your sauna experience…35:25

-How cold affects the brain…43:00

-Inflammation and immune system benefits of cold…49:50

  • Norepinephrine that's released inhibits many inflammatory pathways (TNF-α​)
  • Also decreases macrophage inflammatory proteins (MIP-1), produced by immune cells, and can cause arthritis and other inflammatory-related conditions
  • Improves the integrity of the blood-brain barrier (BBB)
  • Doubles glutathione reductase, increases superoxide dismutase
  • Inhibits collagenase activity
  • Decreased pain response to injury

-The effects of cold on aging…53:15

  • Aging causes the production of immunosenescence
  • Increased lymphocyte numbers (white blood cells)
  • T-killer cells decrease naturally with age
  • Thymosin-α​ 1 peptide

-Cold's effects on fat loss…54:20

-Performance and recovery…58:25

  • Pro-inflammatory cytokines activated right after exercise (exercise-induced inflammation)
  • Macrophages released are associated with muscular atrophy you get with strength training
  • Extreme cold immediately after exercise may not be advisable
  • 15 minutes exposure to 50 °F after running can increase PGC1-α (mitochondrial biogenesis)
  • Timing and dosing are key:
    • Allow body time to produce inflammatory response
    • Save the 10-minute ice bath for 2 hours after exercise
  • Cryotherapy after tennis practice

-Tips and tricks to enhance cold thermogenesis…1:03:45

-And much more!

Resources from this episode:

– Podcasts and articles:

– Food & Supplements:

– Studies:

– Other resources:

Episode sponsors:

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