Beyond Hot Flashes: How Heat Impacts Health & Longevity

Okay. All you hotties out there, listen up. If you are already out there having hot flashes or night sweats, you may first think, oh heck no. But I want you to stay with me. Listen to this episode because there may just be something here hiding in this episode that will help you with your longevity plan, even your menopause plan. But what has getting hot got to do with your health and your VO2 max? We're talking all about it today. Don't miss this one. If you love a good beach, you love a good sweat, you'd rather have summer than winter. And as I'm looking out the window at snow, I am thinking, yes, yes, that's me. Why am I here? I'm like, I need to call my baby Dean and say, look, when it's less than freezing, I'm gonna need to see you more frequently. But I digress. This is all about heat and your health. So literally we're talking today about the benefits of heat, not just sauna. So if you've been hearing about cold plunge and you've been hearing about sauna, whether infrared or steam or any other kind, we're actually just talking about heat. So if you're a hot yoga lover, there's a little science behind this and we're gonna talk about it and how it can impact and improve your heart health and your longevity and make you stronger and more resilient. In this episode, my guest is Bill Gifford. He's written about health, performance, longevity for more than 20 years. He's the co-author of the number one New York Times bestselling Outlive with Dr. Peter Attia and author of Hotwired: How the Hidden Power of Heat Makes Us Stronger. He lives with his family in Salt Lake City, Utah. His book, by the way, is out March 17th, 2026, in which we are talking about the content of. So if you wanna join us, this is like a little book preview. No matter what you think of his co-author. Hey guys, before we dive into this episode, this is a message I'm actually dropping in very postmortem, meaning before we actually go live and publish, but it's been a few days since I recorded this podcast and when I read the bio of the individual I did not realize that this was the case. And yet in fairness, I've decided to publish this because my understanding is that he is somewhat a victim as well. So this is a co-author of Outlive with Dr. Peter Attia. For those of you who are aware the moment we're in right now, it's probably been 3 to 4 weeks right now that Dr. Peter Attia's relationship in the Harvey Weinstein files and that entire can of worms has really kind of exploded in his face. So should someone who co-authored a book and did the work behind the scenes, was not necessarily friends or more than friendly and collaborative with him on a project, be punished for it. And so my decision is to think of the best, think optimistically that that answer is no, and I'm releasing this. You will hear me potentially hesitate for a moment when I read the bio, and that is the reason why. So I wanted to let you know, some of you will catch that. Some of you may, may yet be unaware of this whole circumstance or unaware of the the famous moment, I suppose, that Dr. Peter Attia has had in the news as a prominent influencer and for his book. There's still a wealth of knowledge in his book, not everything that I agree with, and I think he's also reversed or changed his opinion slightly as a responsible professional would do if new science or new proof or evidence came out. We all ideally will walk back an opinion or change it based on what's new. But I wanted to just put this in here so that you understand I'm aware of a reaction that you might have when you hear that name read in the bio. So without further ado, we will go right into this episode. Welcome to the show, Bill Gifford. Thanks so much for being here.

Thanks for having me. It's great to be here.

Well, I told everybody in the green room that I was probably after this not going to want to go work out. I was going to go probably want to use my sauna afterwards. So everybody should be aware that disclaimer, that's where we're leading you. But you said, no, I might want to do both. Before we dive into that and talking all about the heat, which is a very familiar subject to many of the women here for other reasons, uh, how did you get attracted to this topic, this deep dive into heat, health, sauna, hot yoga, all the things?

Um, I think it's more accurate to say that I was not attracted to it at first. And in fact, 5 years ago, If you had said, "Let's go do a sauna," I would have said, "Can we make it short or maybe no thanks?" Yeah, I was never a winter person, never a heat guy. In fact, over my shoulder— never a summer person, I'm a winter person. Over my shoulder is a poster for a winter carnival, a college winter carnival. I like winter sports. Never thought I was somebody who liked the heat. And that was kind of a story I told myself. But about 3 or 4 years ago, 4 years ago, I started going to the sauna in the back of the locker room at my gym. And it's kind of a dark, dank little hot room. Not much to recommend it, but somehow I sat in there kind of usually by myself. And after 10 minutes, I'd sort of feel better. It was weird. And then I'd take a quick cold shower and be on my way. And it became something that I did several times a week, you know, when I was going through— we were having a cold winter and I was going through, you know, a difficult work situation and some other stuff. And it just was like a little refuge. And so, I started getting curious about what did the science around sauna, what does science have to say about sauna? And I was aware that there was some research suggesting that it had potential longevity benefits. And I've written 2 books about longevity, so I was interested. So, I dug deeper and the book is the result.

Okay. And today, so from your first venture into that first time, what's your sauna habit today?

I'm a convert. Um, but you know, I, I do it, you know, there was an old poem where, uh, Allen Ginsberg from the '50s, he said like, I smoke marijuana every chance I get. I kind of feel the same way about sauna. I do a sauna every, every, whenever I can, basically. And it adds up to about twice a week. You know, I go to a local place and hang out, get warm, get hot, jump in the cold plunge, go home, feel better, sleep great.

So you, you swing both ways. Am I hearing that?

Yeah. Yeah.

Okay. So, and I want to come back to that. So a lot of people find Hot days, hot saunas, really uncomfortable. I would tend to say that some of my listeners who right now are having hot flashes and night sweats, that's the last thing they wanna do. They probably think it's going to trigger and sometimes might, but I mean, talk about what about them is good for you. And potentially we need to clarify, is it just heat? Is it any heat or is it, there's a lot of talk right now about infrared. Are you talking any heat?

To a certain extent, all heat is kind of created equal. I mean, if you're talking about if you just want to raise somebody's core body temperature, which is where a lot of the health benefits, which I'll describe soon, take place, really getting in a hot tub or a hot bath is more effective because a sauna raises your skin temperature but not so much your core temperature. But now I'll talk about what these health benefits are that we're kind of dancing around. So, um, they're starting in 2015, a series of, um, studies published out of Finland found that men who use sauna every other day or every day had about 40% the rate of sudden heart attacks and strokes, cardiovascular-related mortality, all-cause mortality, as people who did it one time a week. So that's a huge effect. And that's the— that's the— yeah, that's— these are the studies that kicked off the whole sauna boom, um, as far as, yeah, people being interested in its health benefits.

Yeah, and, and I think that one of the selling points for a lot of people— I mean, given the statistic is 80% of females anyway will readily admit they are not doing the minimum twice-weekly resistance training to improve their metabolic health, right? You know, a lot of people will then hear Sauna is like a workout for your body in ways that, you know, you don't have to get sweaty and breathless. So I think it's very attractive for that reason.

You will get sweaty.

This is true. This is true. Yeah. Yeah. You do a lot of—

There's no way out of that. Yeah. If you're not getting sweaty, something's wrong. But—

So what does the science actually say? Yeah. Yeah.

So it— sitting in a sauna, whether you're male or female, it does something similar to light to moderate exercise. So your heart rate goes up a little bit, or to a lot, depending. Um, uh, you have a lot of skin blood flow. All— basically all the blood in your body goes whooshing underneath the surface of your skin every minute. So it's a, it's a rapid increase in skin blood flow and the, and your body's trying to cool itself down. And so your blood vessels dilate also. And your heart rate goes up. The thing that doesn't happen that happens when you work out is you're not having muscle activation, assuming you're not working out in the sauna. So you don't have the muscle activation piece, but you have the cardiovascular piece and that that takes you, takes you pretty far. I mean, it takes you to cardiovascular benefits, um, lowered blood pressure. It also has— these same studies found that frequent sauna use seems to have a protective effect against Alzheimer's disease. And now the best part for your listeners is that this study was originally done in middle-aged Finnish men, But in 2001, they added women to the cohort and they found pretty much the same benefits in the women.

Wow. And that was my next question. Is there a difference between males and females in any way? You know, I think there's, um, if we look at Dr. Stacy Sims, we'll say maybe cold plunge is not as ideal for women as heat is. I think I don't know, I'm among those women who would say, "I would much rather get in a sauna than in a cold plunge. Thank you very much." Real quick, a little trivia. Hands down, I know from our Community, most women would gladly sleep separately from their partners before separately from their dogs. So if that's you, you're not alone. Look, I would do anything for Moses, But when it comes to dog food, it seems like you have to make a choice. Either fresh and healthy, maybe labor intensive, or you can have easy to store and serve, but never both. But you don't have to choose anymore, thanks to Sundays. Look, we all love the idea of feeding our dogs real fresh food, but the reality is that fresh dog food usually means taking up freezer space, time to thaw and prep, and then a lot of mess when you serve it. Get the good without the hassle with Sundays. It was founded by a veterinarian and mom, Dr. Tori Waxman, who got tired of seeing so-called premium dog food full of fillers and synthetics. What I love about Sundays, you just scoop and serve. No freezer, no thawing or prep, no mess, just nutrient-rich, clean food that fuels their happiest, healthiest days so you get more of them to share together. Moses loves it. Make the switch to Sundays. Go right now to SundaysForDogs.com/Flipping50 and get 50% off your first order. Or you can use code Flipping50 at checkout. That's 50% off your first order at SundaysForDogs.com/Flipping50. SundaysForDogs.com/Flipping50. Or use code FLIPPING50 at checkout.

Yeah, and I'm right there with you on the cold plunge issue. And in fact, I have a chapter called The Case Against Cold Plunging where I sort of question some, but let's start with sauna first and heat therapy in general. You know, it's, I searched around for, studies or data looking for sort of a differential effect, and there is a little bit of a difference. Mostly it has to do with stress. And so when women get into a hot sauna as opposed to men, there's a greater activation of something called ACTH, which is a hormone that's on the sort of cortisol axis.

Mm-hmm.

And so that's a— it's a stress response, and that's elevated as compared to men considerably. Another thing that happens, uh, women's heart rate tends to— there's precious little research about this, but I did see some stuff that suggested that women's heart rate accelerates a bit more than men's in a sauna. And the core body temperature might go up, and skin temperature definitely goes up more in a sauna in women than in men. And I think all those things are somewhat related. It's more stressful. It, you know, I, it may have something to do with, um, smaller body size, so the heat— there's less mass to heat up, essentially. That could be one thing.

Interesting.

Where that leads, you know, on this side of the Atlantic where we don't have a kind of a native sauna tradition and we're kind of listening to what influencers say and they'll give you a prescription, you know, everybody must sit in the sauna for 19 minutes or longer. You know, I think you have to be wary of those one-size-fits-all sort of prescriptions in general, but I think For women, maybe less time is better. Listen to yourself, listen to how you feel, right? And the same goes for, for cold, you know, just because somebody at the contrast therapy place says you have to be in the cold plunge for 2 minutes doesn't mean you need to do that.

Yeah. Good point. I don't think I could do that. Like, yeah, I'm going to be, yeah, I'm going to be gone overboard for sure. But there is something to be said for going back and forth. I mean, I think I could probably tolerate cold plunge after a really hot sauna better than I could just getting in cold. Which seems like you're going to the very opposite extreme. It's almost a much more drastic change. But what happens in that situation? Is there an improved benefit if I come from having heated myself up to, you know, basically in the oven and then go to the freezer? Is there a greater benefit from That?

Yeah, so there are, there are dozens if not hundreds of studies about heat and sauna and its physiological effects. The science on cold is a lot slimmer, and certainly around the benefits of cold, um, it's a lot— you're on, you're on thin ice, so to speak. But if I think Yeah, if you get down to a really basic level, the reason that cold is a part of these traditions is because you, you want nothing more than to bring your temperature back to equilibrium. And so it's— you're just regulating your temperature. That's really all you're doing. You're recovering from the heat and the stress that you experienced in the sauna. That's the basic level. And then, you know, I feel like, I feel like the, the benefits of, benefits of a cold plunge are, are a little bit oversold. This would be good news for you. You should, you should be happy about that. But so, for example, yeah, from a workout perspective, right, if you do a strength workout and then hop in a cold plunge there's a lot of data suggesting that you might be inhibiting muscle growth in response to the workout. So erasing the benefits of the workout you just did. So that's silly. But there are benefits around sort of— The opposite. Yeah?

Yeah, talk to me about this because there is, and I can't quote the study, but I bet you can. So something is frequently said about, the percent of amplification of VO2 max if you get in sauna immediately after a workout. Can you unravel that for me?

Yeah, yeah. So, um, endurance athletes have been using sauna, especially in the sort of Nordic countries, for decades as a complement to their training. And that's such— that started to bleed over into sports like marathon running and even cycling. And so, now, it's de rigueur almost for endurance athletes to end 1 or 2 workouts a week with a little sauna session. I'm in Utah and the 2 men who represented the United States in the Olympic marathon, are based here and they routinely finish their long run or their 10-mile run or whatever in a sauna. And, it kind of— going back to what I was saying earlier, it kind of keeps that cardiovascular elevation, that cardiovascular effect going after you're done exercising.

And so, that's the benefit, the biggest Okay.

Yeah, that's one of them. That's one of them. But then there's a whole other interesting arm of research where they found that sort of dedicated, deliberate training in the heat is similar to altitude training in the sense that it improves your endurance, improves your oxygen delivery, increases your hemoglobin, increases your hematocrit, which is the percentage of basically your body's ability to deliver oxygen. To your muscles in a way similar to altitude training. And so that's kind of a revelation that, that this kind of benefit, this kind of training technique, is basically accessible to anybody. You don't have to go to altitude.

Any tips on— so let's say, let's say those elite runners are doing 10 miles. Now that's different than someone else doing 10 miles because of the time difference, but let's say somebody is doing their equivalent of a, a longer workout or a, a probably significant cardio workout, and then they get in the sauna. For women who might be listening, they often can already have a little challenge regulating themselves electrolyte-wise. Any tips on how do you like front-load with electrolytes, hydration, and/or between, or do you want to Is there a difference in the benefit if you do or you don't?

Oh, I think when you start any kind of, you know, intense or lengthy exercise, you have to be fully hydrated. You know, electrolytes, we get a lot of electrolytes from our American diet. Unless you're consciously avoiding salt and going to great lengths to avoid it, you're going to get enough electrolytes typically. That said, in a sauna session, you can sweat out a liter per hour of liquid. So, you have to be conscious of— my partner and I went to Finland and toured around to some saunas. And basically, the night first day we were there, we went to this really hot sauna in the center of Helsinki. And, we couldn't believe how hot it was. It was our first experience in a true wood-fired intense. It was easily 200 degrees. Her earrings got hot. Wow, this is really hot. And then, by the 4th or 5th time in and out, we're like, "Okay, this is alright. It feels pretty good." But, we didn't drink enough and we didn't consume enough electrolytes. So the next day we wake up and we felt like, felt like garbage. We're like bickering and like grumpy and like wasted and tired and just like, oh my gosh, what happened? And we realized, oh, you didn't drink enough. Just rookies.

Yeah, no, you know, I had an experience, a very similar experience. I was in Minneapolis with a friend. This was right when hot yoga was becoming all the the rage. And I lived in a town where that really wasn't accessible. And, you know, he said, you know, what do you want to do? You want to go get some hors d'oeuvres or cocktails? I'm like, no, what I'd really like to do is go to hot yoga. So we did. And I looked down halfway through, the fingernail polish is melting off my nails. I'm like, this is so wrong. Like, I should not be here.

Yeah.

But exactly the same the next day, I felt like I was hungover and I hadn't had anything to drink. I mean, it was just awful. Yeah.

And, hot yoga takes it to the next level. I went around and kind of tried to measure my sweat rate as I did these different things like in a sauna or riding my bike on a hot day. Hot yoga was the winner by far as far as like how much I could not believe how much I sweated.

Amazing.

So, say a little bit more about that. Right. So you're exerting yourself and you're in this hot environment. And so, you know, no air movement. Um, yeah. And I think what people don't think about as much when they're thinking about heat is that when you're exercising on a warm day, most of the heat you're experiencing is coming from inside you. Yeah, we create— we're like little furnaces. Like, we generate an enormous amount of body heat. And, you know, you know that. Like, if you— you know, um, I'm trying to think of a good example, but so you can go jogging on a, on a, on a pretty cold day in shorts and a t-shirt, right, and be fine, right? Because you're generating so much heat. And so in hot yoga, you're exerting yourself there's no airflow, it's humid, it's really hot, it's hotter than your body temperature. And so you're going to sweat like crazy as your body— as you struggle to maintain temperature equilibrium. And it's, it's a real test, you know. I think they, they did some research and found that like men in hot yoga classes can get their body temperature up to as high as 103, 104. That's high. That's like a fever.

Yes. Yeah, right. Yeah, exactly. And yet there— the funny thing is, as uncomfortable as it is while you're in it, there is something addictive about it.

There really is.

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That part was really interesting, discovering how many, how many of us sort of crave these sort of uncomfortably hot experiences ranging from sauna to other kinds of heat bathing to hot yoga to You know, I did an endurance bike ride in Texas called the Hotter in Hell 100 down in Wichita Falls, Texas. 100 miles, it's always 100 degrees. It's in the middle of nowhere. It's a great event.

Yeah.

And, thousands of people sign up for this thing. Thousands. It's wild.

Do thousands finish?

Yeah, they do. They do. Surprisingly, I finished. I couldn't believe it. I'm a winter person and somehow I trained myself to be able to adapt so that I adapted to the heat. I could handle it. It was no problem. So talking about this, we're just very flexible. We can do more than we think, and especially with regard to climate and temperature, we can really handle an enormous range of temperatures, not only heat but also cold. So if you think about it, you know, when we evolved this ability to sweat that no other animal has, we also lost most of our fur on our bodies. So that meant that when we migrated to places like Finland or North America, we were in these very cold climates, right? And cold is very dangerous for us. It's actually more dangerous for us than heat, and more deaths are related to excessive cold than excessive heat. That's a whole other, um, whole other story. But I think there's an evolutionary reason why we kind of crave warmth and crave hot spaces like the sauna. And the sauna has been around for— there's evidence of sauna-like practices from 12,000 years ago.

So I want to back you up and I want to ask two different things, very related. But one, you said something about I tried to measure my sweat. Were you literally like using a tool or a device to measure your sweat and measure maybe what your sodium output was?

So I was, I was using a very simple tool. It's called the scale. And so let's say you're going to go, let's say you're going to go to a hot yoga class. So you go into your bathroom or you go stand on your scale naked with a water bottle.

Right?

You get your weight and then you go to the class and then you come back with the same water bottle, naked again, weigh yourself, and the difference is how much you sweated. That's, that's mostly, mostly water weight that you lost in that class. And then you can—

so wait a minute, with the water bottle full or empty?

So you start out full, and then assuming you drank some water during the class, then that goes into the calculation, and then the difference You need to account for the water you drank.

Okay, got it.

Does that make sense? So then there's a better tool.

We should repeat that.

Okay, so wait, before— weigh yourself naked with your water bottle, go out and do your thing, come back, weigh yourself again. Naked with the same water bottle. So you can tell, you know, that you can account for how much you might have drunk, right, on your workout.

Okay.

And then the difference is how much you sweat it out over that length of time. Now there's a better—

got it—

there's, of course, there's a gadget for this. There's a gadget for everything. There's a little gadget called the Nix, N-I-X, and that's like a little patch that you put on your upper arm and it is actually ingenious. It collects your sweat and extrapolates, calculates basically how much you're sweating, and it also measures the electrolyte content. And so that's the crucial bit. And it's really— you can see like how much salt you're sweating out, and it varies from person to person and day to day. And so you can sort of understand a little bit how much you need to replace.

Yeah, it's really cool. So true. So when I was training for—

it's awesome.

Yeah, yeah. When I was training for iron distance triathlons, I mean, we would, you know, I knew how much sodium I needed per hour. I knew how many salt licks on my thumb every hour. And that's, you know, also changed dramatically in a hot, humid versus a dry You know, at altitude, you know, it changed significantly. And I, I think sometimes, you know, if you're listening and you're planning to— you're attending a Flipping 50 retreat, for instance, in Boulder in June, you know, and you live somewhere flat in your training, you know, it's going to be different. So we talk about that along the way in training. I want to pivot though and ask you about this. So now, you know, sweating out. We're losing electrolytes and sodium, but you know, there is always that. I think we've just thought, you know, yeah, it's so good to sweat and get out toxins. I mean, talk about how much of that really happens with a sauna. Is that part of the benefit? What are we doing?

Definitely. It's, uh, talked about as, and pitched as, as one of the benefits that you're sweating out toxins, but I think if you ask any mainstream physician, they'll tell you that your kidneys and your liver do your detoxing, and it's not— it doesn't— toxins do not come out of, um, come out via your skin, via sweat. So yeah, I think, I think, I think then I've thought about where does that idea come from, and I think it's because if you're doing a sauna, especially, and especially if you're rinsing off with cold water, you feel purified in some sense. You feel cleaner. And I think the original purpose of the sauna was to clean, is cleaning essentially. It was like a bath before we had showers and bathtubs and all that kind of stuff. But the idea that you're preferentially excreting toxins via your sweat, via your skin, I think is false. The jury might be out though. We don't have great ways of capturing and measuring and analyzing sweat that aren't sort of— especially if you're talking about tiny concentrations of potentially tiny concentrations of things. So, I will allow that the jury might be out. Bryan Johnson, God bless him, does all kinds of crazy experiments on himself, but he did a long sauna protocol and he measured levels of various toxic chemicals in his body and microplastics. And then, after his 2-month sauna protocol, I think it was, measured them again and he found a significant reduction. So, you know, and he has access to tests that most labs don't, right? So you can spend an infinite amount of money and, you know, he found a difference. So I'm not as dogmatic about that as I once was. I think, I think, you know, I always say the jury's out, but so far there's not been a slam dunk study showing, showing that the toxins are reduced in the body. Okay.

Okay. Good to know. You feel good about this, though? I think, yeah, I— there's a lot to be said about that. And I do think— and I— this is not one and the same thing. However, whenever I'm in a sauna, I mean, it's not like— if it's really hot, it's not like you can take your book in. I I think your, your phone could be submerged in water so you could take it in there. But I think it also somewhat is— it's quiet, it's meditative. As a brand new homeowner of an old home, this is one of my favorite sponsors. Did you know that 3 out of 4 U.S. homes have toxic chemicals in their tap water? Even though contaminated water looks clear, it could put you at risk for devastating health concerns including fatigue, hormone disruption, cognitive decline, even cancer. Surprisingly, standard fridge and pitcher filters do little to remove contaminants, and bottled water contains microplastics. So what's the solution? Introducing AquaTru. It's the countertop water purifier tested and certified to remove 84 contaminants, including chlorine, lead, forever chemicals, and microplastics. Its patented 4-stage reverse osmosis system goes way ordinary filters for pure, healthy water you can trust. No plumbing, no installation. AquaTru's been featured in Business Insider, Popular Science, and named best countertop water filter by Good Housekeeping. Join 98% of customers who say their drinking water is cleaner, safer, and healthier. Go to AquaTru.com now for 20% off your purifier using promo code FLIPPING50. AquaTru even comes with a 30-day best-tasting water guarantee. That's aquatru.com, A-Q-U-A-T-R-U dot com. Promo code FLIPPING50. What kind of relationship is there between sauna time mindfulness, meditation, and what happens to brain health via sauna.

Yeah, it's, it's really interesting. And, you know, in our society being the way it is, it, it's really a wonderful thing that your iPhone won't work in the sauna for long, right? I know, I'll get that little red thermometer message or whatever. So that's a great thing. And so we get to escape that. Um, you know, we're either— you can be alone, um, or you can be with other people, maybe other people who you chose to be with. So that's a, that's a benefit as well. It's, it's relaxing your muscles, right? Your muscles kind of soften in that heat. Physically soften. It's almost like taking ice cream out of the freezer, right? It just kind of softens. But then I dug into some interesting research around heat and mental health that actually really surprised me, and it started with hot yoga. In fact, some researchers at Harvard did a study of people, severely depressed people, and they put them on a hot yoga program, basically a Bikram program. Once or twice a week, they'd go to hot yoga for 90 minutes or whatever. And then after 8 weeks, they— I'm not going through the whole thing, but they found that it reduced their, their depression symptoms significantly. And some of them were completely wiped out, like no depression symptoms. And so people have sort of taken that and run with it., and looked at the effect of heat, or what they call whole body hyperthermia. So heating up your body, and does that have an effect on depression? And it, you know, several studies have suggested that, that it, that it could have a significant effect on severe depression.

Hmm. So I'd like you to write me a prescription to a beach about now. Okay. Because I'm all in.

I think you should invest it.

Yeah, yeah, yeah, definitely. Okay. So let's talk about this. So knowing there are, there are such great benefits of getting in the heat, and I'd love to know if like there are countries where sauna is more mainstream, like it is a part of what people do as you've, you know, visited and traveled. What about heat tolerance? As we age, because we know that both— that's an interesting subject. Older adults seem not to tolerate heat. We're always worried about them if the temperatures go up. And so what happens with older adults if we are exposed to something like sauna to our heat resilience?

Yeah, that's a great question. And, um, you know, heat is most dangerous to older people. And when you read about heat waves and people dying in heat waves, that kind of thing, almost entirely elderly people, right? Yeah, who might not have access to air conditioning or whatever. Um, our ability to sweat and our ability to tolerate heat definitely declines with age, except, except Yeah, yeah. Except they found in very fit older people, men and women. Yep. So maintaining a high VO2 max relative for your age and doing heat tolerance training like I alluded to earlier, those two things can really improve your ability to deal with heat to the point where you're essentially like a younger person when it comes to sweating. It almost reverses those effects of aging. So fitness and heat training.

Yeah, it was stunning. Amazing. So in all of your research, I'm going to potentially put you on the spot, not my intention, but I think for my listeners, and I'm going to intuitively ask this question because I've worked primarily with women my entire, you know, 4 and a half decade career. And a lot of times women don't like to sweat. Like, it's a negative. Like, I don't like to do this because I don't like to get sweaty, and/or I feel like something is wrong with me because I sweat so much. And it's always been a hard lesson to convey that, gosh, the sooner you sweat, the better you're doing. Your body's working. Your heating and plumbing system is on. Like, your HVAC is good to go. Yeah. Talk a little bit about like onset of sweat and do older adults who continue exposure continue to be able to like heating and cooling better? Yeah.

So one of the signs of, one of the things that happens with heat adaptation as your body adapts to heat is that you do sweat sooner. You sweat more and you sweat sooner. So sweating is a good thing. But, you know, we have all kinds of messages in our culture and society that sweating is gross, that sweating is something that women are not supposed to do visibly unless they're at CrossFit or some other, you know, some other safe sweating space. And it's almost like forbidden. And even for men as well, you know, you show up to a meeting and you're all sweaty, or you show up to a sales meeting, right? And you're sweaty and it just doesn't— socially unacceptable. Yeah. I should say there's two kinds of sweat. There's gross sweat, and that's like in your armpits and hairy areas, and that's like sticky. Yucky. The bacteria eat it and then they make it make bad smells. So that's one kind of sweat. Sweat I'm talking about is called eccrine sweat, and that's all over your body. We have 2 to 4 million of these eccrine sweat glands, and that's just water and salt. So that's perfectly harmless, you know, there's nothing really gross about it. It's just salty water. Um, and you know, it's interesting I was in New York at a sauna festival in Brooklyn and there were a lot of people of all ages but a lot of women. And sauna is hugely popular among sort of Gen Z especially. And I think it's partly— this is amateur sociology, but partly because it's a safe space to sweat. It's like the hot yoga studio. You can just sweat your eyeballs out. In there and love it. Nobody will judge you.

Yeah, so true. Okay, it's been totally enriching. So do you have a preference? Is it steam for you? Is it infrared sauna for you? Is it yes please, all of the above?

You know, I like a good old good old-fashioned wood-fired Finnish-style sauna with a big basket of rocks and you throw water on it and steam goes up and ideally with friendly people. It's a friend of mine who's in the sauna business calls it, says the sauna is a friend-making box. So, it has this social aspect to it also.

Yeah. Is there— and I know you kind of recommended like where you shoot for and then where you end up— if we were giving them quote unquote a sauna prescription, what would we say is, you know, here's the sweet spot for frequency, or is there one?

I don't think we can say with any definition what the prescription is, um, like I said, I, I go, you know, I try to go once or twice a week, you know, when I could. I— that's kind of what my schedule allows. But as far as like how long to stay in and all that kind of thing, um, listen to your body, you know. I think what I try to do is I go in until I want to get out, and then I stay a little bit longer and push it just a little bit. And then the idea of actually getting in the cold plunge sounds fantastic, um, but I don't—

I don't know, you're really in there.

Yeah, yeah, yeah. And I've done it enough so that I don't— you know, I've— when the first time I got in a really, really hot Finnish sauna, I kind of freaked out, like, this is, this is beyond. But now I can, I I've adapted. I can take it.

Excellent.

Bill, is that specific enough for you?

You know, I think that it is. I think that it is, you know, it's one of those things that until you do it, you don't know. So I probably have told that story about my fingernail polish melting off in that hot yoga. More, more than once. But you know what I, what I remember is that that was funny, and yet I would go back in a heartbeat. There was something about it. Yeah, you know, I'm not there particularly, I just didn't have the opportunity. But I was so intrigued by the idea of what my friend called a triple play. You apparently go you know, in the morning and at night and then the next morning. And I was like, I could, you know, because I felt hungover after one, I was like, I can't imagine that, you know, right now I haven't established any kind of tolerance at all. But the idea I could tell how and why that could become so, so addictive and feel so— I hate to use the word because it's overused, but cleansing. Is literally, you know, just when you need a reset and there's no other place for your mind to be, at least when you're doing hot yoga, you know, you can't do anything else. You can't do the shopping list, you can't do the worry about anything. And I think that's sometimes the beauty of, you know, not being able to take your cell phone into the sauna. And maybe that there is the first benefit right there. Yeah.

Yeah, and you know, for at least for me, I'm concentrating on not falling over. But I would say we're tremendously adaptable, and yeah, you know, if you're starting a practice like sauna, start gently. Be gentle to yourself and take a lot of time to recover in between stints on the bench, and you'll find— you'll either find you like it and you want to do it more Or you want to do something else, and that's fine too. But we adapt, you know, we, we're resilient.

Yeah. Pretty amazing. Yeah. And I absolutely love, you know, all of the new tools that are opening up to us. So in your writing on health and longevity and Hot Wired being, being the book we've kind of talked about, so that is available wherever books are sold. What are you working on next? Can you tell us?

Oh, I can't talk about it specifically, but I'm working on a project that has to do with mental and psychological resilience. So it's not so much physical health at all, but it's more about how to build yourself a better life.

Hmm. Okay. Yes, please. Okay. Okay. I'm in. Bill, where can listeners find you, learn more about you, and of course the book?

I'm on places like LinkedIn and Instagram at @billgifford. Okay. Twitter, if it still exists. And here's the book. I have the book. I just got hard copies today. So we're recording this in advance. So, very exciting to see it in real life. Yeah, you can order it on Amazon or wherever. So good. And when is the release? March 17th.

The 10th? Awesome. Oh, it's St. Patrick's Day. That'll be a good one.

Okay.

Yeah. Very good. Thank you so much for joining us today. Best of luck. All right, everybody, go get hot.

Thanks, Debra.