What Doesn’t Kill Us: Why Your Body Needs Freezing Water, Extreme Altitude & Environmental Conditioning.

Yo, yo. Hello, hello, it is Ben Greenfield and I am actually shivering as I record this introduction for you because I just got out of the cold pool down here in Los Angeles. And yes, I know all of you listeners in Alaska and Wisconsin and Minnesota and the backwoods of Idaho and Washington are snickering right now that I'm complaining about cold weather in Los Angeles. I'm actually at my buddy Tai Lopez's house for a series of meetings and podcasts, etc. Down here in the LA area, which I avoid like the plague. But I swoop down here about every quarter for around five days to batch all my meetings. That's what I do when I have to go to cities I don't like very much. But Ty has a pool that's relatively cold and the reason that I swam in it today was to prepare for today's interview, which is all about what doesn't kill you, why your body needs freezing water, extreme altitude, and environmental conditioning extremes. This is, as you may have guessed by the Tai, a fun podcast. You're gonna enjoy it. It will inspire you to go out and do things like swim in cold slash, admittedly lukewarm water in Los Angeles. In this episode of the Ben Greenfield Fitness Show.

I ended up hiking up this, basically a ski slope in Poland. Now it's in the middle of, I think we were there in January. So you know, this is the winter that stopped Hitler's army. And going up the ski slope bare chested, all I have is boots and a bathing suit and maybe a ha. It takes eight hours. And I think at the top of the mountain, we're talking about 2 degrees Fahrenheit. So really, really cold. And there needs to be a warning here is that though the WIM HOF method is incredibly good at making you hold your breath for a long period of time, it should never, ever, ever be mixed with freediving.

He's an expert in human performance and nutrition, voted America's top personal trainer and one of the globe's most influential people in health and fitness. His show provides you with everything you need to optimize physical and ment. He is Ben Greenfield.

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Hey, folks, it's Ben Greenfield. And I've got in my hand right now this book. And on the COVID of the book is this dude with a badass beard, like, charging out of a lake filled with ice, like leaping out of what looks like a hole in the ice. And the title of the book says, how Freezing water, Extreme altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary strength. That's a subtitle, and the title is what Doesn't Kill Us. And this book goes into, like, how our ancestors crossed the Alps and animal skins and colonized the new world in loincloths and evaded predators and built civilizations with, like, their. Their raw brain power and their inner grit and. And how we've basically turned into giant, plump blobs who rely on, like, air conditioning and heating and cars and who just fricking freak out if if, say, like, the. The. The shower water isn't quite warm enough to make us feel all comfortable. So this book is actually written by my guest on today's podcast. His name is Scott Carney. He's an investigative journalist. He's an anthropologist. His books are actually really good. He has, like, blend narrative nonfiction with ethnography. He reminds me, actually a little bit of another podcast guest I've had on Neil Strauss. He's kind of like an immersive journalist who goes in and gets his hands dirty. And he wrote this book. He wrote another book called the Red on the Trail of the World's Organ Brokers, Bone Thieves, Blood Farmers, and Child Traffickers. We'll hopefully get a chance to talk a little bit about that book as well. But Scott is here on the show with me to talk specifically about this book, what Doesn't Kill Us. And what I love about this book is it starts off with somebody who we've had on the show before, the Dutch fitness guru and cold water enthusiast, Wim Hof. And, Scott, from what I'm reading in the book, you spent a copious amount of time with Wim in writing this thing, did you not?

I absolutely did. And I just want to say, first of all, thank you so much for having me on. This is a real honor to be here. But yeah, Wim and I go back for about almost five years now. And you know, when. And it started off as sort of a funny relationship because I'd heard all of these crazy stories about him, you know, for people who don't haven't listened to your previous podcast, which they should. Wim is this Dutch fitness guru who makes these superhuman claims of being able to control his autonomic nervous system with the power of his mind. He does these crazy feats like climbing up Mount Everest in his shorts and shoes and Nothing else. Submerging himself in ice for, like, ridiculous amounts of time and swimming under, like, ice sheets in the Arctic Circle. I mean, this guy is crazy almost.

Yeah.

He seems superhuman, right?

And also on the flip side, too, he ran. We were talking about this when he was on the show. He ran the desert. I don't think it was the Sahara, it may have been a different desert, but he ran a marathon in the desert with no water to prove that the human body's thirst mechanisms can be held at bay. And you can actually do something like that without dehydration taking you out.

Yeah, it sounds crazy, doesn't it?

Yeah, crazy for some people, fun for some of our listeners. They're probably like, sign me up. Where can I go do this? But for the average person, yeah, yeah, it's. It's a little bit crazy and he's a little bit crazy and. Yeah, I'm curious, what do you think of him? Like. Like, how was that to actually go back there? You went to Poland, right, And did his whole course.

Well, I did. And, you know, when I started this, I thought that Wim Hof was a charlatan, like a total fake who maybe had some really cool genetic abilities, that he was just sort of gifted from, you know, luck of the draw. But he was making these claims that he could train other people to do this too. And I had just written a book, you know, it had come out like a year before, about how meditation and intensive meditation can sometimes end up really darkly. And I followed the story of a guy who died while meditating in the mountains of Arizona, following.

Was that your book? A Death on Diamond Mountain?

Yeah, exactly. And I spent a year.

Tell me about that. Somebody died meditating?

Yeah. Not just one guy. I mean, I've seen a lot of people die on their spiritual paths. When I was in, say, 2004, I was leading an abroad program in Northern India. I'm an anthropologist by training, and I had this group of like 12 or students underneath me. And we went on the silent 10 day meditation retreat in Bodh Gaya, which is the place where the Buddha attained enlightenment. And at the end of the ten Days of Silence, one of my students climbed up to the roof of the retreat center and jumped off to her death. She committed.

Gosh, this is like the ten day Vipassama. Vipassama. Am I pronouncing that right?

Vipassana. It's a relative event.

Yeah, the 10 day Vipassana meditation that a ton of people are doing. Like my podcast sidekick, Rachel, she just did one I don't think she threw herself off a roof. But this is happening in more than.

One case, many cases. And what happened with her is she had written in her journal, you know, I am a bodhisattva. All I need to do is leave my body and I'll get to the next stage. So she thought she was enlightened. And because she was enlightened, she had to die. And that was like a really intense experience, you know, probably one of the most formative things that I've ever gone through. And it set me on a whole bunch of investigations as a journalist right after this, because one of the things that happened, and just to keep this short, I was with her body for about three days after the. And trying to bring her body back to the United States. And that started.

What do you mean you were with her body?

Like, with her body like next to her body? Like, I was responsible. I was the leader of this program and I had to bring her back to America to her parents. Right. And you know, there was a police investigation. It was a, you know, a horrendous event, life changing. But it started me thinking about what the body is as a piece of meat, you know, and that led me off, you know, cause people were fighting over her body parts in really gruesome ways. And we don't need to get into the details, but that ended up.

Oh, but I'm actually curious about that. Why are people fighting over her body parts?

Like the. So when you die, your body becomes basically meat. Right? And you know, the police wanted various cuts of her body for evidence gathering. You know, there was an insurance company that, that didn't want to pay for certain things. And then we were fighting over air travel and ice storage. I mean, it was, it was a mess. And everyone sort of had this stake in her corpse. And you know, I was living in India at the time, and I was also, you know, it started me thinking about how the body becomes an object and what happens when it becomes an object. And it led me into this whole path of investigating organ trafficking. And, you know, you mentioned my first book, the Red Market. I uncovered, you know, a global nexus, billions of dollars of illegal organ trafficking from this. And that's sort of inspired by this event. But, you know, in my second book, I was like, well, okay, she died. That was horrible. But why did she kill herself? You know, how could this search for enlightenment go so horribly? And I looked at cases of many, many people going on these intensive retreats and for various reasons ending up taking their lives or Going insane, ending up in mental asylums. And it's a dark side of the spiritual path that most people don't talk about, right?

Oh no, you hear about people coming back and like their lives are changed and by being silent for 10 days they've whatever, removed their addiction to cell phones and had some business breakthrough, right?

And those. That's. That's true. And that's great. And that's totally there. And I have a great respect for the spiritual journey, but not to. But people, when they hear that there's these bad sides happen, they usually say, oh, that doesn't really happen. And so then I investigated that for a long time and I found I have about a dozen journals of people who died on meditation retreats. And I just, you know, fast forwarding, I had just done this story on a guru who had taught this sort of bastardized form of Tibetan meditation that ended up in another person dying in the deserts of Arizona. So not to get into the details of that, when I met Whim, when I first heard of Whim, I was like, oh God, we got another fake guru. We've got another guy who's saying, hey, you can be a superhuman, right? And that sounds like, hey, you can be enlightened, you can get superpowers. I was like, this guy's gonna kill someone. And so I was like, all right, well I'm gonna go out there and I'm gonna go meet him. Because he's got this training center in Poland. And at this point, Wim was not very well known. I mean he was like this, you know, had some viral videos on the Internet, but not a lot of people knew him.

Had he at that point done his whole deal where he spent like two plus hours immersed in ice?

He had just done that. Okay, yes. But that, that story didn't really get out and really go mainstream until about, about three years after he did it. You know, he did was doing all these feats and sort of not recognizing. It took a while for the, the interest in him to build. And when I had met him, I was one of the, I was probably the first real feature writing journalist, you know, with a credible reputation to go meet him. And I did this story for Playboy. And what I was going to assume was going to happen was I was going to go there, he was going to make these crazy claims and I was going to just watch people get sick and hurt themselves. And then I was going to be like, okay, we've got another one of these guys. Avoid Wim Hof at all costs. But I'm a journalist and I'm an anthropologist and I believe that you have to give your sources a fair shot. Like even if you have these notions, you have to look at the evidence and go in there and I meet him and he's just like. I don't know if you've seen pictures of Wim, but he's a pretty muscled guy, but ruddy face, big, bulbous nose, looks a little like a life size garden gnome.

Oh, yeah, sure. I mean the podcast that we did with him. And I'll link to it in the show notes, by the way, for those of you listening in, just go to BenGreenfieldFitness.com HarderToKill that's BenGreenfoldFitness.com HarderToKill and I'll link to the previous podcast that we did with Wim. But yeah, we actually did a video podcast. I remember when we started the podcast, he was playing me a song on his guitar. He was making up a song on his guitar about the podcast. So, yeah, interesting guy. So you met up with him.

So I met up with him and I fly into Wroclaw in Poland and then we drive into the mountains and there's only three people. I mean, he's really an unknown guru at this point. It's me and two other guys basically who are, who arrived and maybe they had two other people sort of hanging around the training center. And we get there and the first thing I see is one of the people who was already there. You know, I'm stashing my, my, my bag at the, in the bunk and whatever. And I look out the window and there's this dude, not whim, in his underwear, sitting on a snowy field, throwing snow on himself. And there's steam coming off his body. And I'm like, what in the world is going on here? Right? Like, and also my mind is also saying it's like, hell no, I'm not going to do any of this. But that night Wim and I sort of hang out. We're playing a game of chess and just talking and I beat him. For the record, I beat Wim. But then he's like, you should really try the training. It would be really good. And I'm like, all right, I'll give you a shot. And the next day he does this breathing method. So the Wim HOF training method is basically environmental conditioning and a breathing routine. And he teaches me the breathing routine, which is like hyperventilation and then holding your breath and hyperventilating, holding your breath and all of A sudden, I hold my breath for like a minute and a half, which, you know, before then I could hold my breath for maybe like 30 seconds. And that was pretty cool. I was like, oh, I'd never done that before. And then at the end of the session, he's like, okay, do this breathing method one more time. Let all the air out of your lungs, and then just start doing push ups. Now, at the time, I was, you know, I'm not super fit, not like really out of shape, but, you know, I'm not like one of your average podcast listeners who's. Who's ripped. Right. I. I was a normal dude. I could do about 20 push ups and then 20 push ups.

With normal breathing?

Yeah, with normal. And I'm breathing while doing the push ups. Right. And then Wim's like, you're gonna do. You're not gonna breathe at all. You're gonna have empty lungs and you're gonna do push ups. And I. And I did it. And I did 40. I doubled the amount of push ups I'd done before, and I wasn't breathing, and they were easy. And that was crazy. It was like, opened my eyes. I was like, oh, my God, how does this body hack suddenly make me. In just the course of an hour, let me double the amount that I'd done before. And I was like, all right, I'm going to give him a shot. There's obviously something really cool here. And over the course of the next week, you know, we do this stuff where we stand in the snow. And the first time you stand in the snow, and all of your listeners are currently thinking, hell, no, I'm not going to stand in the snow. That sounds terrible.

You'd be surprised. All right, well, they're like, I know we've got a few people out there taking cold showers, but yeah, not a lot of people have gone and done what you did. So you're standing in the snow with this guy.

Yeah. And maybe your listeners are like, this guy's a wimp. Right. But I stand in the snow and.

He'S one of those skinny journalists with the tight, skinny jeans who is bragging that he stood in the snow.

Exactly. Right. And five minutes, he's like, you're just gonna stand up for five minutes. And you get there and it hurts. It hurts terribly. It is really bad.

You're in your bare feet. Right, Right. And actually a little rabbit hole here. Sorry to interrupt, but my kids and I were sitting, all of us were sitting around the dinner table last night, and I'm like, my feet hurt, my toes hurt. I feel like I have burns at the bottom of my feet. My son river says it says, me too, my feet hurt. And Terrence, as my feet hurt. And it turns out that our morning habit since the snowfall has been going out to dip in the hot tub or the cold pool outside our house. But we run from the front door, it's about 100 yards. And we run in our bare feet through the snow. And all of us right now have skin burns on the bottom of our feet. So yes, it's uncomfortable.

Yeah, that totally can happen. So we stood there for like five minutes and it hurt like terribly. And then we went into the sauna right afterwards to warm up. And that hurt even worse. Right, because your response to the snow is all the veins in your feet will constrict.

Right.

And if you're with those muscles, because you've got muscles that line your vasculature and the only way you ever use those muscles is actually trigger them using an environmental stimulus by using the cold so they're weak. Right. And so just like lifting weights when you haven't lifted weights before, it hurts a lot. And so, so it hurt in the snow. And then we went into the sauna and it hurt again when those veins dilated and they relaxed. And that was actually even worse. And Wim was like, well, don't worry, the first time you do this is going to be the worst. But, but you know that panic moment where you're like, I can't take it anymore, that's gonna recede. And the next day we do the same thing. We stand in the snow and I last 10 minutes before I get to that same point of where like, I can't do this anymore. And the next day we do it again. I'm there for 30 minutes and the next day we're there for an hour. And you know, we're chest bare to the sky, we're just in bathing suits, basically barefoot, and we're just standing in the snow. And I could do it an hour before I get to that point where like I have to get inside. And that's just. Can you imagine three days and that level of progress? It's sort of amazing how quickly the body can adapt to that environment. And we do other things. We go into snowy ice filled rivers and we dunk ourselves in there. And then we meditate on the side of the river. And I'm melting all the snow around me because I'm generating so much heat.

Did you do any self quantification? Of your body prior to going and hanging out with whim and doing these activities. And one of the reasons that I asked that is, you know, for example, you know, Wim, when I had him on the show, was talking about how he, you know, he freaking injected himself with an endotoxin, I think it was E. Coli. And found that his combination of breathing and cold exposure actually enhanced his immune system's response to be able to fight that off.

Right.

But I'm curious if you. Did you just go and write about this or did you do any tests on your body?

I wasn't expecting to do the training with him, so I didn't at that point. I hadn't done sort of a before and after test. Now later as I get into writing the book, I did do that a lot more and I think we'll get to that a little later in the show. But at this point what I'm seeing is just I knew how many push ups I could do, I knew how long I could hold my breath. And what I was seeing is that these were like doubling and tripling the amounts of time and really rapidly. And I also knew what my weight was. And at the end of the trip I ended up training with him. I ended up hiking up this basically a ski slope in Poland. It's in the middle of. I think we were there in January. So this is the winter that stopped Hitler's army. And going up the ski slope bare chested, all I have is boots and a bathing suit and maybe a hat on. And it takes eight hours. And I think at the top of the mountain we're talking about 2 degrees Fahrenheit. So really, really cold. And the whole time I'm sweating, like the whole time I'm going up this mountain, I'm sweating. And there are skiers coming down who are like doing double takes. And some. One snowboarder actually fell down. I was like, oh my God, look at these people. And, and the whole group is like, is like burning up. Because what we learned is that the body is designed to be able to handle extreme environments. Like we evolved over the, you know, our species is 200,000 years old. You know, that's, that's. You're genetically identical to, you know, this caveman 200,000 years ago. And we've only had like modern conveniences, you know, like super awesome wool garments and weatherproof whatever and modern heating for like 75 years, maybe 100 and so years. Like that's nothing, right?

The ability to be constantly warm. I mean it's not like our ancestors would have walked around naked in the snow, right? At least like not as a habit.

Interesting you should say that because. So there's this story that Americans tell every year at Thanksgiving, right, where the Pilgrims, you know, these religious outcasts from Europe land in basically Cape Cod, you know, Massachusetts, and they are starving in the winter. They have their little cold huts and, you know, I'm assuming those ugly hats with the buckles on the front and they're freezing and starving and they don't meet anybody in the New World until in, I believe it was February. No, no, no, no. Anyway, it's in the dead of winter, maybe it's March. A Native American named Sam Osett walks into their camp wearing nothing but a loincloth. And that's all he's wearing, just a loincloth. And the first thing he says to the, the settlers are welcome. Welcome, Englishman. Do you have any beer? This is the founding myth of America. You can look this up. Samoset's his name.

Samoset. How do you spell that last name?

S A M O S E T. So you know, the way he knew English is a long, complicated story, but involves him being kidnapped when he was younger and by English fishermen. And they taught him some English and apparently also what beer was. But the fact is that this guy, you know, maybe a 20 something year old guy, is walking around in the middle of Cape Cod in nothing but a loincloth.

And it was cold in Cape Cod at that time.

Oh my God, yes. I mean this is like Boston, right? This is Boston in the winter. We're talking snow, we're talking wind, we're talking. And Cape Cod's exposed. Like it's low lining.

I've been to Boston in the winter. As a matter of fact, I was in Boston. Do you remember last year during the, the cold snap that Boston had? It was like the coldest day on record in 50 years. I'm gonna tell you this just because I know you'll respect me for this. After having done the wim off thing, I had a 40 hour race outdoors race in Vermont that weekend. It was called the Spartan Agoji. And it was 48 hours of orienteering and rucking and burpees in the snow and all manner of different activities. But. But yes, Boston. I couldn't imagine hanging out in Boston in a loincloth in the winter, that's for sure.

Well, apparently Samoset had no issue. And the first thing the settlers did was give him a coat. And he was like, yeah, great, thanks for the Coat, guys. And it turns out the Pilgrims. Samoset becomes the reason why the Pilgrims survived. He eventually introduced them to the other Algonquin natives and the Wampanoag and these other tribes there. But was it. But the really cool thing for the terms of what I'm talking about here is that the people of Massachusetts at that time wore barely anything in the winter. And what they did instead is from a very young age, they would put their children, babies, infants, and put them in the Snow for about 15 minutes a day to acclimatize them to the environment. And these kids grew up really robust and able to withstand the environment with no trouble.

Yeah, that's something that I've come across before. There's a book called the Paleo Manifesto by John Durant, and he goes into how not just several different Native American tribes, but some Russian tribes or Russian populations and some other folks who have very hardy, like, warrior populations who are known for being tough and resilient. They all have this strange practice of exposing their children to cold from a very early age, repeatedly, whether it's snow or cold plunges. And that's one of the reasons I talked about how my kids have snow burns on the bottom of their feet right now. But from a very early age, they've been doing several times a week, cold plunges, cold soaks, and cold showers. Because I happen to have read that book by John when they were pretty young. So I'm like, well, if it worked for them, maybe it'll work for us. Social Services hasn't wound up on my front doorstep up quite yet. But, yeah, my kids, they dig the cold. And so this makes sense.

And, you know, it's one of these things that humans just have an innate ability to resist the elements. You know, we're born with a tissue. You know, when an infant is born, they have. They're very small, but they have a high surface area to mass ratio, which means that they lose body heat very quickly. And also since they're infants, right, they don't have a musculature that's very developed. They don't have a digestive system that's very developed. And they lose heat incredibly quickly, which is why we put premature kids into incubators, right? So they need to be warm. But because they can't warm themselves with muscle action or digestive action or any of these normal ways that humans eat themselves, instead they have tissue called brown fat or brown adipose tissue. And this brown fat is this. Is this tissue which is, you know, what. What scientists call thermogenic which its only responsibility is to suck white fat from the body and create heat energy directly out of it. And it's incredibly efficient at doing this. And this is why babies are able to survive the first years of their life, is because they rely on brown fat to heat their body. Now, until recently, most physiologists and scientists and doctors thought brown fat more or less disappeared as people get older, and they rely on other ways to heat their bodies. And it wasn't until about 2007 that we discovered that actually brown fat is active, but it's only active in people who are continually cold, who are actually exposing themselves to cold environments. So normal people will lose effective teeth by the time they're about 20 years old. But if you're in cold environment, this tissue remains in your body and will still allow you to generate heat in a way that we usually don't think is possible. Which is one of the reasons why the WIM HOF method is so interesting, is that you actually will build up stores of bat in your body by exposing yourself to cold, which is a great way to lose weight. It's a great way to just stabilize insulin levels.

And insulin, there's adiponectin, I know is another hormone that gets vastly accelerated or increased when you do that type of cold exposure. So you mobilize more of those fatty acids. And really, when it comes to fat loss, it's kind of cool that you can actually empty out white fat cells or even convert them into other cells. And there's a really interesting anecdote. There's another book I'm reading called Deep Nutrition by Kate Shannon. And she goes in that book into how much you can actually accelerate that process of fat cells, not just shrinking, as would happen if you dieted, but actually getting converted into other tissues, including brown adipose tissue, especially if you're in a state of low inflammation. So she's big on eliminating vegetable oils like omega 6 fatty acids and vegetable oil. She says that's the number one thing that keeps that fat cell conversion from occurring. So I would hazard a guess, you know, folks are listening in and wanting to get more brown fat or get some of that white adipose tissue converted into other tissues. One of the first things you could do is start looking at the label of the foods that you eat for canola oil or for any other heated oils or oils that might be rancid, because it turns out that that inflammation related to oil consumption is the one thing that could inhibit that process you just described from occurring. It's really interesting, huh?

Cool. I never heard that. But the cool thing about doing this with Wim in the first time in Poland is that I lost seven pounds of fat in seven days. It was basically a pound a day that I was losing by doing this cold exposure with him, which is great. And I know that I was losing fat because it was coming out in my stools every day.

What do you mean the fat was coming out in your stools?

Well, I don't know exactly. I wasn't handling it, but it was a greasy yellow sludge.

So it was floaters.

Something like that. Yeah. And hopefully your listeners are like, wow, that's amazing. I want floaters too.

Oh yeah. My listeners love to talk about poop. So you spent this time with whim. And I love some of the stories that you write in the book. It's especially impressive how towards the end of the book you're like standing on the top of Mount Kilimanjaro, having gone from early in the book knowing nothing about this guy to having climbed a freaking mountain with him. And did you climb it wearing a minimal amount of clothing like I've seen him doing in his shorts, for example?

Yeah. And the whole goal of the book was to work up to one of these really big events. And almost the whole way up, I was just in a bathing suit. There were two times that I put something on, basically one in a low valley, 50 mile an hour winds and chill. And I was just, it was horrible. And I put on a sweater and it felt like failure. And then I took it off a little bit later. And then right, right near the top of the mountain, you know, I put on a sweater again to get to the top.

Did you ever get like, during the course of this time that you were doing this, did you ever get skin burns?

No, never Once.

Wow.

So when you're hiking up the mountain, one, your body is just naturally using energy and they're generating, and therefore generating heat. So that's like the normal exercise. And if you go for a run in the winter and you choose to, you know, let's say you're wearing your fleece, right, you're going to be sweating up a storm in your fleeces. But you know, if you do it without, you're still generating heat. And actually it can be reasonably comfortable. But as you get into these more extreme things, some of the whimsical method is very useful to increase the resistance to sort of environmental, you know, catastrophes. And there's this breathing method and there's a sort of mental focus that you get into and it, and it's really weird because you know, when I'm like say starting a race, you know, or something like that. And you know, in the winter I'll be really cold when I have my sweatshirt on, you know, getting up to the, the starting line. But then I take it off and, and it's like this sucking feeling. Like things just sort of like, like it's like I'm putting on armor and, and it feels like cold just doesn't penetrate. Like you just sort of like keep it out of the mind. And, and I'm sure this is a lot of just mental juju that's going on, but there's, there's something that I actually don't feel cold, you know, for the duration of the, of the event, which is really bizarre. And also it fills me with endorphins and adrenaline.

Probably a cluster of factors, you know. Dr. Rhonda Patrick, or have you heard.

Before, I'm familiar with her.

She talks a lot about how cold exposure not just elevates ironically heat shock protein, which can increase stress resilience, but also of course nitric oxide vascularity, capillarization, all these things that cause your blood to be far more efficient at cooling you and also make you less likely to just, just shunt all your blood to your organs and your brain in response to cold exposure, as would happen in someone who hadn't done the type of things that you did to train your body to prepare for cold. You talk about some really interesting things in the book. For example, one word that you use throughout the book is this term wedge. That was one that I hadn't seen thrown around before. When you use the term wedge, what is it that you're referring to?

Yeah, this is the way I think of what's happening with the body in the WIM HOF method. And it's sort of the, the, you know, it's the word that I use is because what happens, the way you train yourself to take control of autonomic functions, and that's the claim that WIM makes, is by finding a pre programmed environmental stimulus, right? So let's say the cold. But this could also be heat. This could also be altitude. This could be a number of different, different factors and then knowing in advance what sort of reaction that your body is going to have to that response, right? And then what you do, and this is the very heart of the method is you resist having that response. So in the cold, for instance, you know that you're going to eventually shiver in the cold and what you, the way you gain control over your body is you resist the shiver. And that is what I call the wedge. You're putting this sort of wedge between the environment and your autonomic functions by using your conscious thoughts. And you know, one, one way I try to describe is like, let's say you have to sneeze, right? You have allergies or something, you can feel that sneeze coming on. But if you want to, oftentimes you can delay or even stop that sneeze by just, you know, thinking un sneezeworthy thoughts or, you know, whatever it is you do in your body and in your mind, you can stop that from happening. And that's like essentially the technique that Wim uses in to control almost anything, including eventually his immune system itself. This is how he was able to resist endotoxin. There was this environmental thing coming at him and he just willed his body not to do it. And it's probably the same way that we learned to do anything from childhood, right? The first time we, we move our arms, we're saying, I don't know how to move my arms. And you think, okay, I'm going to try. And you start to do it. And you can just keep on learning new things about your body by using this technique. And then once you resist it, then you also sort of gain some measure of conscious control over triggering things in your body.

That's interesting. It's like that whole concept of the mammalian divery fucks, like that sharp intake of air. I first ran into that when I interviewed somebody who you actually talk about in the book James Nestor about, oh, I love that great book Deep. And it was reading his book that inspired me to go take a free diving course in Fort Lauderdale. And then now I'm hardcore into. Well, not hardcore, but I'm into spearfishing as a result of taking that class and reading that book. And it's fantastic. But the interesting thing is for me, for example, for cold showers, after having done them for several years, I get into a cold shower and there is no sharp intake of breath. There is no mammalian dive reflex. It's almost like I have buried that reflex and can will myself to not doing it. And I'll have friends who will come here to my house and go do a cold plunge with me. I'm not saying this to brag, just to highlight what you're saying. And they'll get into the pool and you can see their heart rate goes up, their face turns red, and they start, you know, breathing like that. And what I explained to them is that when it comes to the toning of your vagus nerve and the activation of your parasympathetic nervous system and your ability to kind of like shut down that mammalian dive reflex, one litmus test that I will use on myself and on others is if you can just hop into your shower, step into your shower and put it in cold water and not have that sharp intake of breath or get into a body of cold water and just have it look as though you stepped into a bathtub. That is a very good sign of parasympathetic nervous system health. And it's. Do you ever test your heart rate variability, Scott, Your hrv, Have you heard of this?

No, I have no idea what you're talking about.

Okay. That's the best way to test whether or not your nervous system is actually robust and healthy. It's the best way to test the tone of your vagus nerve. So I measure it every morning and I post my scores to Facebook. When I measure this, I use this app called, called called Nature Beat. You put on this little heart rate monitor in the morning. A lot of athletes, a lot of professional sports teams, it was originally these professional soccer teams in Europe who used to do this all the time to predict injury, to predict over training, to predict illness, but also just to look at a player's data and say, okay, this player is ready to train hard this day, or this player should take an easy day. And you can do the same with your own body. But one of the best ways to get it up is with cold exposure, with cold water exposure, with cold baths, things like that. And what I find is that my clients who I train or the people who have the highest HRV scores, they're usually the people who don't complain at all about the cold showers and who usually have it as a core part of their daily routine.

Oh, cool. How do I measure it?

You need a Bluetooth enabled heart rate monitor and you need an app that will measure. I use an app called Nature Beat and you just pull it up. I do a five minute morning measurement and it's one of the most useful ways to measure your body. I'll put links to this stuff stuff in the show notes for those of you listening in. By the way, I mentioned that the shownotes were going to be@BenGreenfieldFitness.com HarderToKill and then I realized I have another podcast at BenGreenfieldFitness.Com HarderToKill with a gal who I interviewed about how to make yourself harder to kill. So we're going to put the shownotes for this one over@BenGreenfieldFitness.com HarderToKill2 that's harder to kill. The number two. Sorry that you're second place, Scott. But for those of you who want it, who want to check out Scott's book and some of these other things we're talking about, all the show notes will be over there. But that's really interesting about that wedge.

I do want to say one thing though before we move on, which is that you mentioned the master switch, which is the dive response and there needs to be a warning here, is that though the WIM HOF method is incredibly good at making you hold your breath for a long period of time, it should never, ever, ever be mixed with free diving. Because the free diving method is a different way to hold your breath for a long period of time. It uses different signaling. And if you do the WIM HOF method, you'll probably drown. You'll have this thing called shallow water blackout. Because what WIM does is it's hyperventilating and you're blowing off CO2 from your system and your body cannot sense oxygen, it can only sense CO2. So when it gets poisonous levels of CO2, it says, we got to go breathe. So what Wim's method does, it blows off all the CO2, which allows you to do more exercises. And on land, that's great. However it makes it, there's a potential for fainting. When you do this method and faint on dry land and you're like sitting down or whatever, whatever, you're going to be fine. You're going to get back up, you do it underwater and you're going to die. And several people have died by mixing off stuff in water.

Some guy. We were doing this in my living room last week. I had a group of guys over and was leading them through some Kundalini yoga and some Breath of Fire and stuff. One of the guys just fainted, you know, right there in the living room. And you can just imagine, you know, if, if he did that, but he was like six feet from the surface of the water and we were out in the ocean, you know, you. It's Bad News Bears.

Yeah, definitely. And, and you know, the free diving techniques are great and the WIMP stuff is great. And Wim does stuff in water and I think he's been lucky a lot of the time because of it. And so just be very, very careful when you do it.

Yeah, absolutely. I agree And I do a lot of underwater hypoxic, cold water swimming in this little pool that I have outside my house. But A, I'm really careful. I always stop when I'm at like 60% of where I think I need to be. I never push myself that hard. And B, I always tell tell everybody where I'm headed when I go to that pool. Like everybody knows where dad's at. If so if dad doesn't come back out in like five minutes, then they know to send out the search parties to go fish me from the pool. You have a cool routine that you talk about in the book that I'd love to hear you describe where you're doing like power push ups and then you have like this 15 minute daily workout that you do. You kind of described, you know, your initial experience with WiM, having you do push ups with your breath held. But can you describe how these power push ups are work and Also this new 15 minute daily workout you've developed as part of writing this book, right?

Yeah. And my workout's a little bit different from wims, but it's definitely a relative of it. And what I do is every morning I'll sit down, usually with my wife who does the training with me, and then we'll do three rounds of the breathing method, which is one round is 30 breaths, 30 deep, quick breaths. And it sounds like this, right? And you'll get a little dizzy. You'll have some. Your fingers will maybe tingle. And after 30, you let all of the air out of your lungs. Not force it so your lungs hurt, but just out. And then hold your breath. And so the first round, I'll hold my breath for a minute and then I'll take one recovery breath, which is just like a half breath in, and hold it for about 10 seconds. And then I'll repeat the process. So then I'll do another 30 breaths and then I'll retain with, with air out. And then that's another. Now I'll do two minutes of retention and then I do a third round and I'll hold my breath for three minutes. And that's the basic breath hold. And if you hit three, you're doing really good. Not everyone can, but it's just sort of where my physiology is at the moment.

Okay, got it.

And then after that, then you do one more round of breathing, but maybe you do 40 breaths and the last 10, maybe even a little faster. So you're blowing off all the CO2 out of your system. And then I let the air out of My lungs again. And I immediately just do push ups. Whatever sort of push ups you want to do, just know what you're doing.

So you're doing push ups. So you've gone through a full exhale. And then you start doing the push ups.

When you've exhaled the air right, without breathing. Now you're holding your breath, so you're.

Not taking a big breath like this. And starting in your push ups, you're breathing everything out, holding that and then starting the push ups with the air already exhaled from your lungs.

Exactly. And then I'll do usually about 50 push ups in that sort of state. The most I've ever done is 80. And then I sort of like hit my head on the floor at the end of it. But yeah, and so then, you know, then I'll do like an inversion, you know, you know, headstand, basically.

Okay, gotcha.

And then done. That's about 15 minutes. And then, you know, I usually hug my wife because I feel really, I have like all these endorphins running through me. And then you go jump in the shower at some point, you know, somebody can start off warm. And then you end up with about a minute of cold water at the end and you're ready for the day.

I like it. So three rounds of power breathing and then at the very last one, you read everything out. You do 50 push ups with the breath held out. And then you finish up with a headstand to let the blood move to your head. And then you go onto a cold shower.

Yep, that's it. Cool.

I like it. I may have to try that one out or else I'll guinea pig it on my kids, which I'm prone to do sometimes when I don't have enough time to try the workout myself, I have this white. I have a white stack of papers on the kitchen table. And when my kids wake up, I always have something written out for them to do. Like today. Sometimes it's simple, but I try to teach them little things. Like today I set out. Have you ever heard of a dry skin brush?

I know. What's that?

It's like this. I think it's ayurvedic, kind of like coconut oil pulling. But you take a brush and you just brush your entire body up towards your heart, so all your extremities towards your heart. And it moves because it's a very light action against the surface of the skin. It moves lymphatic fluid through the body. So it's really good for the immune system during cold and flu Season and it's almost like a form of self washing, self care how animals will lick each other or mothers will wash a baby. It's kind of like doing that to yourself. So it's almost like a really cool way to take care of your body as well as a form of as woo woo as this may sound like self love. Anyways, so I, I do dry skin brushing a couple times a week. I'll just brush my whole body. It takes three minutes. So that was their workout this morning was 15 minutes in the sauna and then they finish with a full body dry skin brush. But perhaps tomorrow I will have them do this. If my kids faint, I'm going to blame you. And once again, social services are probably going to wind up on my door if they listen to this episode.

Regarding fainting, do this within limits. And and there's always a risk of fainting with this sort of workout because you're dealing with breath. But it's much more likely that you'll pass out if you do a full breath retention and then push ups. So if I want to do the absolute maximum number of pushups that I could do, I would do the same thing and then I would take a full breath of air, then I'd do push ups because then I have more air in my lungs, so more energy to use. However the body can't. It really throws off the way the body detects CO2 buildup when you do that and you don't really see the blackout coming on. So that's actually a little bit more dangerous in the sense of fainting.

So if you take a full breath and then do a bunch of exercising, you're more likely to faint than if you breathe out. And then that doesn't seem to make sense to me because when you breathe out, wouldn't you be breathing off all the CO2? That would be your body's signal to take a breath.

Yes, but you now have empty lungs. So as your body processes the oxygen that's in your blood, it then fills up your lungs with the CO2 because that's the byproduct and you haven't exhaled it. So then it reaches that alarm bell earlier. Whereas if you had full lungs, the gas exchange doesn't detect it as quickly.

Oh, fascinating. I wouldn't have thought about it that way. Okay, that makes perfect sense. Interesting that it's okay, so you breathe out everything and then you do the exercise. You do power push ups or I would imagine squats or pull ups or anything like that.

Yeah, I mean you Know, again, pull ups, squats, pull ups, leg lifts, whatever, sit ups, any of those variations will do. But again, you know, if you do pull ups, you know, you pass out, you know, then you're falling something. So work up to those bigger exercises so you know where your limits are. And then, you know, as you said, Maybe only do 80% of where you think you can. Right?

Yeah, that makes sense. I don't want to give everybody the impression, by the way, that this entire book is about climbing mountains in your underwear with Wim Hof because you did some other things. Like, for example, you went and did the Laird Hamilton underwater workout. Can you describe how you got into that and what happened when you did that?

Yeah. So I have a friend named Scott Canale who actually did a really cool documentary about obstacle course racing, the Suffer Fest.

I know, Scott. I've seen this. Yeah, yeah. As a matter of fact, I don't. I'm not into documentaries. I. I will watch, like, one documentary a year. And I went to the screening of his Suffer Fest down in San Francisco and brought my wife and my kids, too, and we were all enthralled. Like, we loved it. It was hilarious. And for those of you who don't know what it's about, I mean, Scott just, like, traveled around the world, figured out why people do these crazy masochistic events. Kind of similar to your book, Scott. But, yeah, it's a great, great film. Anyways, though we digress what you're saying.

He was working on the film the same time that I was working on the book, and we've just been corresponding for years. And I was like, you know, Scott, I need to find an athlete who does the Wim Hof method, and who do you know? And he was like, wait, you don't know Laird Hamilton, most legendary surfer of all time, the guy who surfed the heaviest wave ever? And I'm like, no, I never heard of him. And he was like, let me get you his number. So I called him up, and it turns out Laird is a huge deal, and I'm just an idiot for not knowing who he was. And he's got this great pool in Malibu near Los Angeles, where it's full of celebrities. Like, when I went there, Orlando Bloom was there, John McGinley, who was the guy in Scrubs and Platoon, you know, lots of these always.

And by the way, I've done the workout down in Malibu with Laird a few times. And yeah, you always get in the pool, and there's always, like, celebrities in.

The pool, which is pretty awesome, right? Yeah, you're. And Laird starts doing the day with doing power breathing, pretty similar to what I do, and also a cold shower pretty similar to what I do. And then, then he takes the routine into the pool, where instead of doing the blowing off CO2, the most simple thing he does is takes dumbbells and lets with £50 or so, enough to drag you straight to the bottom, 12ft, goes to the bottom, and then gets into a squat and then jumps to the surface, takes a breath of air, and then goes back down and just keeps on doing these, I think he calls them underwater power jumps. And just rep after rep after rep. And every time you get to the bottom, you push up, take a big gulp, and you do like 20 or 30 of these. And it's interesting because at first it's not terribly difficult. You have energy from the push up and then from your feet, and then you have a stroke down with your arms. But you start running at a deficit, it pretty soon. And, you know, he sort of trains you by putting you under this stress over a sort of long period of time to do more and more. And the cool thing about the workout is because it's underwater, you. It's a really, really low impact.

Yeah. Yeah. That's the crazy thing is these workouts. A lot of times in Malibu, like, people will show up to his pool at 8am and, you know, the first time I went, I. I showed up at 8, myself and Neil Strauss went over there. We showed up at 8. We were there until 11 in the pool doing all manner of back and forth. You know, we're doing farmers walks under the pool, doing the deal where you tread water with the dumbbell held in between your thighs. Back. They call them the seahorses. Doing the one you described, right? Like those power squats, you know, for a hundred reps, where you're down and up and down and up. And the next day I felt like. Like barely anything in terms of actual eccentric muscle damage, muscle fiber tearing. But you get an enormous cardiovascular training effect and also all the beneficial effects you talk about in the book of Hypoxia. But I'm curious what you thought was the most difficult move in that series in terms of all the workouts that you did in the pool. What do you think was the hardest exercise?

You know, I didn't think any particular exercise was too difficult. And I think that's important for the workout because you are dealing with water. But the thing is, when you do more and more of them, they can get increasingly difficult as you're battling oxygen deprivation. So I think that even just the normal underwater power jumps can be very, very hard. The more you, the more you push them. And we did this one thing where we swam back and forth the pool three or four times underwater laps. I mean, that was pretty hard because you're really, really running low on oxygen by the end of it.

Yeah, yeah. That's something that Bear Grylls, actually, this is talked about in the book the Oxygen Advantage, where Bear Grylls was preparing to climb. I don't remember which mountain he may have climbed Everest anyways, though, like, he didn't have access to, like, an altitude training tent. He didn't have access to altitude to train at. And so, like, the majority of his workouts was just breath hold training in the pool where he was doing hypoxic swim sets like that, just like swimming back and forth. I don't think he was using like the dumbbells or anything like that. That uses. But, yeah, all he did was just swim back and forth. And by the way, that. That's a good book. You'd probably like it. It's right on. On par with some of the stuff we're talking about. The Oxygen Advantage is the name of that book. It's really interesting, though.

Another cool thing that happens when you're underwater. It's one of these we always called the master switch earlier, is that your actual heart rate will always be suppressed in water. So you're actually doing these exercises, lifting these weights with a heart rate which is not elevated. And that probably does a lot of things to your physiology.

Yeah, absolutely. And. And I know one of the things when it comes to, like, the, the lower heart rate that you see in, for example, free divers is they'll get so low and their heart rate will drop so low that their. Their spleen compresses and they release a whole bunch of new red blood cells. So it's actually like, like blood doping. I think James Nestor talks about that a little bit in his book, you know, about how that's why a lot of Olympic athletes, for example, are now learning how to find free dive just so they can get that spleen compression and the release of red blood cells and not to kick a horse to death, but that same book I just mentioned, the Oxygen Advantage, it goes into how hypoxia and breath holds can achieve a similar stimulus not quite as big for the spleen specifically. It allows for the release of or the production of more erythropoietin by your marrow, which is basically the Same stuff, the EPO that a Tour de France cyclist would, would inject into their body. You can get it with the activation of the spleen, with breath hold or with deep diving, which is when that heart rate drops. It's super interesting. Now, one thing, cool.

All the ways we can hack the body, right?

That's why I love this book, man. And you go into how, of course, as the title would imply, what doesn't kill us, how a lot of these ways we can make the body stronger are things that our mom probably told us not to do when we were a kid, like go outside in the snow in our underwear. You talk about a method, for example, that one could use that involves more like pill popping. You know, we talked about brown fat, for example, and thyroid. I think this is a great illustration of kind of like the alternative thought pattern in terms of trying to achieve this stuff through, like, popping pills. Can you talk about that? Because I hadn't heard about this before, like some synthetic thyroid hormone that allows like, brown fat conversion from white fat or activation of thyroid tissue.

Right? Currently it's experimental, but, you know, the idea was when the NIH discovered that brown fat was like a real thing, that that it, it can suck white fat from your system, generate heat, and then you'll slim up, they were like, this is the great way to fight diabetes and the obesity epidemic around America. And what we want to do is find a pill that will mimic the neurotransmitter releases and hormonal releases that will activate brown fat without people getting cold. Because, you know, we don't want people to affect their sedentary lifestyles. We still want to be sedentary if we can, but a pill would be great if we could do it. So there's a bunch of research all around the country and actually all around the world looking at a way to trick the body into either producing or activating bat stores. And one clinical trial that I talk about in the book is by a guy named Kevin Phillips at Baylor University in Texas, who was looking at trying to figure out why the body would activate brown fat. And he started looking at the thyroid, and there was this. The inner biology is a little complicated, but basically there's this hormone called IRIS that will activate and turn on brown fat. And then he created a hormone that sort of is a precursor to it called GC1 that will basically turn on brown fat, and it's based off a thyroid hormone. And what he did is he found two genetically identical mice that were genetically pre programmed to be obese. And he put them into a cold chamber, like a freezer, like a freezer cage, and doped one of these genetically identical mice with GC1, which supercharges your bat, basically. And in the course of, and I don't have the page in front of me, but over the course of several hours and then days, the mouse dosed with GC1 was totally fine and actually was losing weight really quickly, whereas the other mouse died, basically died of hypothermia. Yeah. You know, you look at the graph of these two mice in the, in the article, and I'm assuming it died because the mouse core temperature of the undoped one just falls off the chart and I assume that means death. And the other mouse sort of, I.

Believe in the cell reports journal, they refer to it as fatal hypothermia.

And the other one just, you know, chill. He's totally fine and he loses a bunch of weight. So then in the book, I post this photo of the fat mouse next to the skinny mouse. And it's just the power of brown fat was just shown very clearly in this study. And now they're doing human trials and trying to attenuate this perfectly for the miracle fat loss pill. But at the same time, and the reason why I write this in the book, and I really go into depth on the pharmaceutical approach approach is that I sort of feel like it misses the point. A little bit of what all this training is about and why brown fat and the cold is really interesting, is that while they might be able to figure out how one particular mechanism might work in the body, the body has like dozens of, maybe even hundreds of responses to the cold that aren't bat, that are modulating insulin, that are vasoconstriction, that are doing all like a number of other activities in the body. And. And you're not going to get those benefits if you get a, if you get a pill that just attenuates brown fat. And there was another study that I mentioned in the book where a, a doctor in Holland, Wouter, what's the. Van Markenlichtenbelt is his name. He. I know. I was like, this is a long Dutch name. This is my problem in the book. There's lots of Dutch names in it. He took two groups. No, sorry. There was one group of diabetic men, so the obese diabetic dudes. And he put them into a cold room, I think it was about 53 degrees. And he kept them there for three hours a day for two weeks. And what he was trying to measure was, will this do two things. One, will it build up bat? And two, will it modulate their insulin production and help them sort of control their diabetes? And at the end of the study, he did scans of their BAT before and after, and he found that over the course of two or three weeks, the men's insulin resistance improved by 53%, which means they basically reversed diabetes over the course of two weeks just by sitting in a cold room and watching tv.

That'd be interesting to see because there are other things that have been been shown to restore pancreatic insulin production, like ketosis, for example, is one thing, or at least restriction of blood glucose, or the use of things like metformin. Or what I use as an alternative to metformin is bitter melon extract. But it'd be interesting to see how much you could accelerate that process by putting a lot of these things together, like ketosis, cold exposure, or metformin. Yeah, it's interesting how these type of things can literally push the reboot button.

On the body totally. And in this guy's experiment, so he measures and he finds that diabetes for these guys is basically reversed. It's 53% improvement. And then he measured their bat and he was like, of course, BAT is the reason why this fixed up. And he found that there was absolutely no change and no buildup up in their BAT over the course of that time. And he was really perplexed. How would we get all these benefits without bat? And further studies showed that they were actually building up mitochondria in their muscle tissue instead of in their fat stores. And it turns out that the body has lots and lots and lots of solutions to problems. And with the cold, it can be like, well, I can. I can ramp up my metabolism by building up eit. I can do it in a different way. I could try to insulate myself more. It makes these different decisions. It can make you feel cold, so you do more exercises. It has all these different things that it can make you do. And we don't know beforehand what it's going to choose, but it's going to choose the optimal path. Now, if these guys have been doped with a bat increasing drug hormone, who knows if it would have improved them? Their body didn't think that was the right response.

Yeah, yeah, it's really interesting. And you also, by the way, you talk about heat, you talk about soldiers and what happens to. I thought it was really interesting what happens to soldiers when exposed to heat acclimatization. Can you describe what happened to these Soldiers, like turn them into super soldiers from the use of heat.

I don't know if I'd call them super soldiers, but you know, obviously the United States military, and there's a whole military chapter in this, they want soldiers to be effective in any climate. You know, our stated mission is to be able to fight three wars in three different continents at any time. So that means your fighting force needs to be able to go from.

Wait, what did you say the mission is?

This was, this was like, I think, I think we have to fight three wars on three fronts at any time. That's our military capability is what we're supposed to be able to do. This is probably a 10 year old, maybe 20 year old directive. That's just what America is supposed to be able to do, really.

So when we train our soldiers, technically we're expecting them to be able to fight three different wars in three different climates?

No, we're expecting the army to be able to do it. Not necessarily every single soldier, but certainly soldiers might be based in Hawaii and then get sent to Alaska. Right, right.

Yeah, it makes sense. I just never heard that before. That's really interesting.

So we have all these soldiers in America based all over the places, and we're sending them to places like Afghanistan in the high mountains, or into Iraq where it's very hot. How do you get a soldier to be effective from day one? Because if they're not, they might get heat stroke. They could be ineffective and a mission could fail. So there's a whole research center just outside of Boston that's looking at, you know, ways to adapt people quicker. And they found the quickest way to adapt someone to heat. And this is what they do now is they ship people to places like Arizona where it's pretty warm before they go to Iraq, and they have them work out every day in the heat before they go. And that will actually acclimatize them incredibly quickly. A process that could take three weeks. Normally can get down to like 10 days if they just run in the heat. And there's this study by an Israeli doctor, let's see about, I think it was about a year ago, maybe a year and a half ago, who took mice again and heat acclimatized, acclimated half of the group and didn't heat acclimate the other half of the group and then banged their heads real hard effectively with a mini mouse guillotine to create a brain injury.

And there's absolutely no reason he couldn't have done this in humans, just randomly with mice.

I mean, the government does own soldiers bodies, so they could have done it, but they didn't. So you banged these mouses heads and then she then waited, I think it was about 80 days to see how their brains healed at the end of it and the heat acclimated. So this is a simulated traumatic brain. And the heat acclimated mice, after she dissected them so they were dead at that point, healed markedly better, like, you know, incredibly better than the mice who were not heat acclimated. So the doctors that I was studying with, that I was interviewing at U.S. aerium, the environmental research center for that the U.S. army does to train soldiers, were like, this is great. Now we can say if we heat acclimate soldiers before they go into Iraq and they get hit by an ied, they're going to survive better if we acclimate them in advance. And that's a huge, huge finding.

Seems like it would have pretty interesting implications for like UFC fighters or football players, for example, for tbi for them to be doing things like sauna sessions and heat acclimation. I'm not sure if it's heat shock protein or what, but yeah, it was really interesting. You point out how the mice adjusted to the new climate and had like gaping wounds in their gray matter and. And they still did. Or the mice that didn't get the heat acclimation had like the gaping wounds in their gray matter. And the other heat acclimated mice just healed up fine from getting like pounded on the head by a mini chaotine. Yeah, yeah, Fascinating.

It really is. I mean, of course that's a mouse study, not a human study. So you know, anytime you cross species it could be different. But it certainly seems like there's really good reason to heat acclimate.

Yeah, absolutely. I'm a fan of both. I mean, I don't know about you, but you know, the more of this research that I see, the more I go out of my way to. My rule is every week I have to get into a sweating environment that almost makes me want to like break open the doors and go running out of the sauna and screaming. So I do like at least one session a week where my body just gets really hot, like uncomfortably hot hot. Then I try and do one session a week where my body just gets really cold. And then I do mini sessions during the day. Like occasionally I'll step into the sauna, occasionally I'll take a cold shower. But yeah, this concept of variable temperature and forcing the body to react to these fluctuations in temperature, it's like A lost art. It's like a lost skill. Which is why I loved your book.

It's a third pillar of fitness, is what I say. It's usually people say diet and exercise. Diet and exercise, that's going to be the way to get you fit. But if we forget that you have to do that in a sort of environment, then your temperature controlled gym may not be the optimal way to get fit. Right. Or maybe you got these chiseled abs and you look real awesome, but your circulatory system is junk because you're not exercising this response that can only be exercised in the cold. Like, you can't vasoconstrict consciously. Well, you can. If you do this method a lot, you can actually learn to vasoconstrict consciously. But you usually can't. Right? You can't just say, I'm gonna go, you know, flex my circulatory system right now. You have to get in the cold and then it squinches shut and then you get into the heat and then it opens up and that's a rep. That's like lifting dumbbells.

Yeah. And you can, you can. I think Wim is who talked to me about this when I had him on the show about like the yogi who was able to just like sit there and stare at his hands and turn them bright red not through vasoconstriction, but just through conscious vasodilation. Because he had done a lot of this like breath of fire type of training and could literally with his mind direct blood flow to various parts of his body, which to me seems very useful. It could, could potentially put Viagra out of business. Who knows if we teach enough men this tactic.

But yeah, I have, I have a note about that. So when I was with Wim in Poland, you know, it's just a bunch of dudes hanging out. And I asked him, you know, when we're jumping into this icy cold lake, I was like, can you get an erection? Can you do that, Wim? Are you able to? And so he jumped in there. He's like, yeah, I think I can do it. I think I can do it. So. Oh, like in the cold, in the cold lake.

That's actually, that's funny because I'll do these cold plunges sometimes and. And I'm not shy about admitting the fact that I certainly do like morning sex and afternoon sex more than I like evening sex. It's just like, that's my chrono rhythm. And by the way, I interviewed this really fascinating sleep researcher named Dr. Michael Bruce, who talks about how different chronobiologies have different names. There's a lion, there's a bear, there's a wolf, and there's a dolphin. And he actually has a whole, a whole graph in the book about what the best time of the day is for those different chronotypes to hook up.

Oh, funny.

You know, so, so, like, my wife is one chronotype and I'm another. And so, so for us, it's like 9am and 7pm and a lot of times if I'm doing like, finishing up my workout with like a morning cold soak, I am pretty useless after that cold soak for. Oh, right, for a good hour in terms of blood flow. But it sounds like whim as he's unlocked the secret of, of fighting the shrinkage. Huh.

So, so he says, I mean, I'm not an observer to that, so I don't know. I just have to put.

You don't put on goggles and go underneath the water to see what's happening.

No, but I will say that I, that I did experience full retraction, which is a very unusual feeling.

Right. Seinfeld esque retraction. You called it full retraction. That's. That's a nice, nice term for shrinkage.

Yeah.

Anyway, anyway, on that note, I think probably we have given F folks enough reasons to actually go out and grab this book and give it a read, because I think it's fantastic. It really got the dials in my brain spinning about how important a lot of this stuff is. It'd been a while since I'd kind of delved into all the different benefits of hormesis. Right. There's books like Antifragile by Nassim Talib and that other one I mentioned, the Paleo Manifesto by John Durant. But you do a good job pointing out altitude and freezing water and heat conditioning and environmental conditioning. It's a really good book. And we didn't even scratch the surface of you going over to the UK and doing the tough guy or the crazy things that happen to your fat and carbohydrate oxidation rates and some of the other things that you go into in the book. But folks, if you are listening in, well, worth a read. What Doesn't Kill Us by Scott Carney. And again, I'll put a link to this and everything in the. In the show notes@bengreenfieldfitness.com HarderToKill2 BenGreenfieldFitness.com HarderToKill2 what were you saying, Scott?

Oh, we're also gonna have an audiobook out soon, too, so that'll really narrate. I have narrated. I sat in my closet for two weeks and just narrated, and it actually sounds awesome. So that'll be out maybe not right on launch date, but within a week of that.

Yeah. Cool. And this podcast, I think, comes out just shortly after that book is released. But it's like early January, right?

Yeah, exactly.

This book comes out. Yeah. Awesome. Very cool. I would highly encourage people to give it a read and watch that documentary, too, if you get a chance. That Rise of the Sufferfest documentary. That one's kind of a good accompaniment to this book. So if you need any other excuse to go out and do a tough mudder or a series of cold showers in 2017, you now are equipped with everything you need.

Yeah, do both.

Thanks for coming on the show, man.

Yeah, it's been awesome. Maybe we'll do it again sometime.

Oh, for sure. All right, folks. Well, until next time, I'm Ben Greenfield, along with Scott Carney signing out from BenGreenfieldFitness.com have a healthy week.

You've been listening to the Ben Greenfield Fitness podcast. Go to BenGreenfieldFitness.com for even more cutting edge fitness and performance advice.

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