Dynamic Dialogue with Danny Matranga - 132: Hot and Cold: Sauna, Cold Showers, Red Light, Cryotherapy + More with Dr. Mike T. Nelson

Episode Date: October 13, 2021

In this episode, Danny sits down with Dr. Mike T. Nelson to talk about all things temperature as it pertains to health and human performance. Topics include:Sauna use/guidelinesInfrared vs. Standard saunasRed Light TherapyCold Water Immersion/Cold PlungeCold ShowersCryotherapy Contrast/Hot to Cold+ More!Dr. Mike T. Nelson has spent 18 years of his life learning how the human body works, specifically focusing on how to properly condition it to burn fat and become stronger, more flexible, and healthier.He’s been called in to share his techniques with top government agencies, universities and colleges, fitness organizations and fanatics. The techniques he’s developed, and the results Mike gets for his clients have been featured in international magazines, in scientific publications, and on websites across the globe.Check out Dr. Nelson's work below!PodcastWebsite--- Thanks For Listening!---Grab the new Female Physique Advanced HERE!---RESOURCES/COACHING: I am all about education and that is not limited to this podcast! Feel free to grab a FREE guide (Nutrition, Training, Macros, Etc!) HERE! Interested in Working With Coach Danny and His One-On-One Coaching Team? Click HERE!Want Coach Danny to Fix Your S*** (training, nutrition, lifestyle, etc) fill the form HERE for a chance to have your current approach reviewed live on the show. Want To Have YOUR Question Answered On an Upcoming Episode of DYNAMIC DIALOGUE? You Can Submit It HERE!Want to Support The Podcast AND Get in Better Shape? Grab a Program HERE!----SOCIAL LINKS:Sign up for the trainer mentorship HEREFollow Coach Danny on INSTAGRAMFollow Coach Danny on TwitterFollow Coach Danny on FacebookGet More In-Depth Articles Written By Yours’ Truly HERE!Support the Show.

Hey, everybody, welcome into another episode of the dynamic dialogue podcast. As always, I'm your host, Danny Matranga. And today I'll be sitting down with physiology expert Dr. Mike T. Nelson, we're going to have a nice in depth conversation about temperature exposure, specifically, cold water immersion, cryotherapy, hot sauna use, and various ways in which we manipulate our external temperature to drive physiological outcomes. Everything from recovery to inflammation to cardiovascular response. We're going to have a lot of interesting discussions for you guys today. So stay tuned, relax, and enjoy my conversation with Dr. Mike T. Nelson. Mike, how are you doing? Good. How are you? I'm doing very well out here in California. Where

are you at? I'm in just north of the Twin Cities in Minnesota. California, are you in? I'm in Northern California, Sonoma County, wine country. Oh, beautiful place. Yeah, not a bad place to be stuck inside all day. I'll tell you, we're starting to get towards fall. The leaves are changing colors, but we're getting 71 degree afternoons and 49 degree evenings. Oh, that's perfect. Yeah, it's tough to beat. So today's conversation, we're going to talk a lot about sauna use, cold water immersion, cryotherapy, all of these different things. But before we get into it, why don't you tell my audience a little bit about yourself? What got you into the physiology, fitness, performance enhancement space and what you're working on now? Yeah, probably like most guys, I got into it just to get better at

liftings. I got crushed by just the bar in high school without any weights on it and failed the presidential fitness test. Like every year I took it, I think I was in like the bottom 20% or something, um, which was annoying because they didn't really show you how to train. They just tested us and like, Oh, too bad. You suck. Sorry. We're not going to show you anything, which was annoying. Um, so I started college my first year, even after puberty, I was six, three and 153 pounds. So it was kind of a eel-shaped break, was very not athletic at all. In high school, balls would hit me in the face because I don't see in 3D, which I didn't know at the time. I just thought, I'm just bad at sports and that's just the way it goes.

And then going to college, I was like, oh wow, you can take classes on this. So I took anatomy and physiology for fun. And one of the colleges I was at was one of the rare places where as an undergrad, anyone who took anatomy and physiology got to use human cadavers, which is at St. Scholastica in Duluth, Minnesota. So I did a Bachelor of Arts in natural science there and then opted to do two years postgraduate work at Michigan Tech, the UP of Michigan for engineering. So I stayed on there and did another two and a half years to do a master's in mechanical engineering. Did mostly biomechanics coursework. Research was actually building a ray gun to zap a bunch of monkeys. Okay, okay.

The military has it declassified now it's called active denial system. Oh, wow. Literally a large microwave transmitter on the back of a vehicle. You pointed at a crowd of people and because it's in the gigahertz range, so it's in this, what's called a millimeter wave or super high frequency, but very, very high power. It'll feel like your skin is being burnt by a light bulb, but there's no deep tissue heating effect because of the spectrum that it's in. And the research I did was just running a computer generated model of, you know, is there any deep tissue heating effects? Turns out there isn't.

It actually hasn't been used a whole lot. I think mostly just because of bad press that would be involved. But after 9-11, every branch of the military wanted one for non-lethal crowd dispersion. But then they realized that the headlines of X group uses ray gun on group of protesters probably doesn't sound real good. It sounds like this Havana syndrome thing that I've heard of. I don't know if you're familiar with this. This is some type of, they think it's some type of, I guess you would call it a weapon, some type of basically, I don't know how to describe it other than it's a weapon that impacts acutely how you

feel. It can make you feel very sick. And it's happened all over the world. And I think it might be Russia behind this thing. They call it the Havana syndrome because it first started. But the people who have experienced it have been higher up in particular branches of government. And it's some type of bioweapon that influences you and makes you feel not so good so the minute you started talking about a ray gun that you walk around with i was like okay hold on maybe we're getting somewhere uh but it turns out a buddy of mine had it tested on him when he was in the military and he's like yeah if you're in the beam he's like it hurts really bad but he's like the second you're out of the beam um you're

okay and several years back i did uh some consulting for darpa so the defense defense advanced resource projects agency and one of the guys i met there i was just talking to him about this and he's like oh yeah i was one of the people who was one of the like you know the operators of it i was like oh really i'm like does it work he's like yeah it hurts really bad and i'm like so what do you do like if you're using it he was in iraq at the time and someone is still coming towards you and they're in the beam he's like oh we shoot him i'm like what he's like oh if they're staying in the beam and they're still coming at you he's like they're clearly a threat so we neutralize the threat you can't just turn the just turn the heat up and fry them right there.

I think this is actually a really good segue, ironically, into what we're going to end up talking about, which is different temperature exposures in athletics and performance and longevity. Specifically, very, very cold exposure and very, very hot exposure. Things like cryotherapy, cold baths, and saunas. So before we kind of pick one side or the other, maybe talk a little bit about physiologically why we are so influenced by extreme heats and extreme colds and why this has become such a popular thing amongst fitness enthusiasts, biohackers, the whole lot. Yeah, I've been trying to figure out why it sort of became popular.

I'm not really sure. I mean, I think Wim Hof probably has a lot to do with popularizing cold and breath techniques, which is awesome. If you look, it's fascinating if you travel or if you've been able to travel before everything, whatever happened, happened. or if you've been able to travel before everything, whatever happened, happened. Pretty much every culture has some history of hot and cold type therapies. You'll find a lot of Russian banyas, different bathhouses.

You'll find cold pools. You'll go to Finland and there's a lot of sauna use there. I've been to Finland a couple of times. Oh, nice. Literally everybody has, pretty much everyone has at least one sauna. They may have one in their house. They may have one at their cabin. They may have one outside down by the lake.

So you find a lot of different cultures, especially as you get more so away from the equator where you've got more extremes in climate, you tend to find use of both cold and heat. And yeah, so I'm not really sure exactly why it's become more popular per se, but it definitely seems to be the kind of trendy thing right now. Yeah. You really nailed it with the Wim Hof thing. I think that's what started kind of, or catapulted it into the mainstream, at least within the fitness community. And, you know, like as much Joe Rogan just has so much influence. I think that he had Wim Hof on, and I think that he had Ron DePatrick on.

And Ron DePatrick is a big proponent of sauna use. And Wim, of course, is all about the cold exposure. And I think that kind of helped this stuff maybe leak out into the mainstream weekend warrior type who want to get the most out of their health. And so if we're talking first, let's talk about sauna. We'll start with the hot stuff because we brought it up. What are the differences? Because there's multiple different types of saunas and infrared is very popular now. And then we have maybe more of your traditional heating element driven sauna, like what you might find in these saunas in Finland. Or if you go to a local gym,

you're usually going to have a big heating element with some rocks in there. What are the main benefits of sauna? And then are there really drastic differences between maybe infrared sauna use and the conventional sauna? Yeah. So if we all go all the way back and go, okay, why would we even bother trying to alter our temperature? Yeah. Which I think is a question that just kind of gets lost. Totally. So if we look at physiology, to me, temperature is something I call a, it's a, it's a homeostatic regulator is a fancy word. It means that core temperature can't really deviate too high or too low. Cause if it happens too high or too low, all sorts of really, really bad things happen and you die.

So your body has all these regulatory things that are in place that try to prevent you from going too high and prevent you from going too low. And because of that, we can go into saunas, we can go into cold water, we are adaptable. And just like training, we can expand our capacities to both heat and cold. But the core temperature doesn't really change that much. And if you look across physiologic systems, there's a few others that overlap with that too. So pH is another homeostatic regulator.

Carbon dioxide, oxygen is. And then probably fuel systems, ketones, and blood glucose. So I think we can train these different systems and that'll make us more robust, resilient, anti-fragile, whatever buzzword you want to use around it. We did the Nassim Taleb reference there. We love it. Yeah, which is cool

because we are applying a little bit of stress to the system. If we do it in an intelligent manner, just like training, the system actually gets a little bit better. So in terms of sauna, if you look at the research, it depends on what group of population you're looking at. If we look at untrained individuals, you can see some aerobic benefits with sauna that match light level training. Now, if you look at a trained population, those benefits kind of go away. There is a cardiovascular benefits. There's a bunch of studies out of Finland that's looked at mortality rates are dramatically lower, you know, sometimes 20, 30, even up to like 40% lower.

That gets a little tricky because if you've ever been to Finland and done sauna there, it's, it's just part of the culture. Yeah. It's very much a social thing. You're also, you know, fuck naked most of the time too. Um, but it's a, it's a social nature and people do do it by themselves in their house too. So I think it's sometimes a little hard to tease that out when we're looking at these very long

hemological studies. But there's lots of good data that shows for just trying to live longer, it's beneficial. We look at mechanisms, the multiple mechanisms, but the main one is something called heat shock proteins, and that the heat and cold do upregulate these specific proteins. That probably confers a fair amount of the benefits. If you look at athletic performance, if you are going to train in the heat, you can use it as part of your accommodation or climatization protocol. We do know that just sun exposure to heat in and of itself will increase something called plasma volume. Okay.

Just how much fluid you're able to move around in your body that'll go up a little bit and if that's generally higher your aerobic performance is going to be a little bit better so there are a fair amount of benefits with that i think some of the benefits that are oversold a little bit are, I haven't seen a conclusive study yet that sauna will add any amount of muscle mass. Um, there was one study that just came out recently. And if you actually read it, it it's horrible. It's a disaster, right? It showed bone increase and it showed right mass increase in the leg only. It was just the trash and fire of a study strange um yeah so differences in them most of the research is on the conventional type saunas just because they've been around longer they've got a lot more data if you go to countries like finland that's you know 99 of their

sauna use um the infrared ones are are interesting i haven't seen too much of the data the question there becomes you know how hot can they get and because some of the the rays are a little bit more penetrating it's if you've ever done one it feels really weird yeah i've actually only done uh infrared sauna once almost all of my sauna use has been in the conventional saunas yeah yeah the infrared one and again they're all different and i guess there's some newer ones that can get quite a bit hotter but it was weird i was sitting there and i'm just like you've got it cranked all the way up and i'm like i don't feel much and like 10 minutes later i'm like hey i actually am kind of sweating and it felt like I was being baked from the inside out, like a Turkey in the oven or something. It was weird. How does it, how does that even work?

Like, it's not super complicated to understand how the conventional sauna works. You're basically stepping into a 200 degree Cedar box, but with infrared temperatures are substantially lower. How are we heating the body? Are we getting penetration from these infrared waves? How does that even occur? So my understanding is, not to freak people out, but it's kind of like a microwave, which is probably a horrible analogy. But my understanding is that the waves do penetrate below the skin. They're a different wavelength. So in general, if you go up high in wavelength, your penetration depth starts dropping off real shallow. So if I'm in the gigahertz range,

my penetration depth is about a couple of millimeters. So if I made a microwave oven and I made it in a gigahertz range, I would burn the outside of the food and the inside would be completely frozen. So basically every frozen burrito and every hot pocket that's ever been made. Right. Yeah. And I think your microwave is 2450 megahertz. I could be wrong on that somewhere around there. So it's designed at a little bit of a relative lower frequency so that those waves are penetrating, excite water molecules and create heat. My understanding with the near infrared saunas, it's the same idea. It's just a slightly different frequency with that. And there's some benefits too. You get into the photoviolet modulation, red light therapy at different specific wavelengths. And there's

some pretty cool data on that too, actually. Yeah, that might be worth talking about because I think red light therapy as a tool, it's become quite popular. Again, that's something that I might attribute to maybe Ben Greenfield. I don't know who made that go mainstream, but I remember about three years ago, I started seeing ads for red light therapy pretty much everywhere. And when I look at like, okay, things that are cold, like cryo, cold baths, cold showers, I would put something like red light, maybe more, things that are cold, like cryo, cold baths, cold showers, I would put something like red light, maybe more towards things that are hot, not because they get particularly hot. If you've ever used them, and I've only used the panels like two or three times,

I actually used them once when I had a pretty alarming outbreak of eczema that just kind of came up out of nowhere. And I've seen some of the research on photobiomodulation on skin health. And so I said, Hey, I'm going to blast this with the red light panel. I said to my friend, can I borrow your red light panel and just see what the hell happens? And it worked pretty well for that. I think, of course, I was applying like lotions and ointments too. So it's really hard to parse out maybe what caused that. But for people who don't know, what is red light therapy and does the actual color of the light have to do with why it's different from something like just walking out and getting traditional light exposure?

Yeah. So red light is primarily designed to be a little bit more penetrating and it's in a specific waveform. So depending on the literature and what you read, there's different waveforms that may have different benefits, but there's more of the waveform that kind of creates the red light itself. And then there's a specific waveform that's more what's called near infrared, which you can't really see, but does, you can feel a little bit of heat from it and that's a little bit more penetrating if you look at the literature the fancy word is photobiomodulation and the main theory as far as i understand it it's interacting with something called the cytochrome c oxidase and the mitochondria

that's helping provide more energy to the mitochondria although the I don't understand 100% how that works because there has to be some cost somewhere for that. I'm not entirely sure on that component. I mean, I have one here. I've used it off and on for about like three years. For aerobic performance, it does seem to help. You do have to titrate up in dose, sitting relatively close to it, you know, 10 to maybe 12 minutes a day, maybe a little longer, depending upon how powered it is. The one I have is just a two panel one. There's some data for injury recovery. There's some data for TBI use. So friends of mine who do a lot of clinical neurology, they're kind of big fans of it.

So there's more data that's impressive on it than I thought there was initially. So when I first heard about it, I was like, ah, that just sounds like kind of a gimmick. But if you look at the data and even for athletic performance, it's pretty interesting. I think there's enough there to say that there probably is an ergogenic or performance enhancing effect. Now the caveat is, you know, how close were you to the light? What frequency did you use? What power was it? How long did you use it? What did you actually measure? Because the research on performance is still kind of across the board because there's lots of variables on it. Totally. There's a lot of different red light products on the market. So like if you've been somebody who's considered using it, I would do as much research as you could to make sure that you're getting a panel that's going to actually penetrate and help you get what you want infrared sauna for what it would cost to get a full body, high quality red light panel. Like they're not cheap, but the laundry list of potential benefits in literature to support it is kind of surprising. Like I remember myself when I was like, okay,

this seems super gimmicky. Like let's just go into one of the, I won't say the name, but like one of the more well-known manufacturers of red light products going to their kind of marketing copy on their website and looking at all the different stuff that they say, and then scrolling all the way to the bottom to all the asterisks where they supply the sources, the resources, the literature. There's a lot of actually really, I would say, robust research being done on this right now that it's quite promising. And so I think when you look at the stuff we do to maybe modulate our temperatures in the hot range, we got hot rock sauna, traditional sauna probably being

the most well-studied. We know that that's going to help us with, if we're deconditioned, maybe aerobic adaptations, and we can lean into it maybe releasing or reducing risks of all-cause mortality, which are both reasons in and of itself to consider using it for general population. What about some common things people often associate with sauna use, like relieving or releasing toxins from the body and things like skin. Do we have any, or do you know of any definitive research to kind of support or refute those claims? Because those are thrown around a lot. Yeah, I don't know too much about the skin one, to be honest. The detox one, there actually is some data on that. There are

some toxins that can only be released via the sweat glands. That's from Dr. Brian Walsh has some good information on it. And there are studies showing that. So that was one of those things that initially I was like, it sounds like BS, but there's some pretty good human subject studies on it showing that sweating certain toxins out may be the thing. Yeah, it's interesting because I've heard quite a bit from people who love to use sauna that a lot of the detoxifying benefits, if you will, are largely overblown. But I've also seen literature that shows a lot of heavy metal transfer from high sweat rates. So maybe these two things just haven't fully talked to each other. But if somebody was looking to implement sauna use, and their goals are conventional fitness goals, body composition related. I want to look a little better. I want to move well. If this helps me recover at all,

what would you recommend for that person in terms of maybe number of sessions a week, durations of session a week, and then considerations like, should you be drinking fluid in the sauna or should you be trying to tough it out? Yeah. So the nice part about sauna is there isn't much of an interference effect. Meaning if you're doing training for hypertrophy, for more muscle strength, aerobic benefits, you can get in a sauna immediately after, and it's not going to screw up with any of those mechanisms on a molecular level. That's great. So the nice part is

if people ask me about sauna, I'm like, yeah, great. Just go for it. There isn't really any negative side effects. There is a potential, I think for enhancing aerobic performance because it does hit slightly different pathways. But again, if you're a trained athlete and you've kind of maxed out the amount of time you can aerobically train, I think you may see a little benefit from sauna. Again, there's no randomized controlled trial on that yet. Um, for convenience and for most people, I think post-session is a great time to do it. Um, if you think about what's going on, especially with weight training, you're going to be in more sympathetic stress state. If you think about what's going on, especially with weight training, you're going to be in more sympathetic stress state.

And so I like using sauna immediately after just to do some very light breathing, some longer exhales, just chill out, not sweat for a while. Anecdotally, like myself and clients I've had do that or the heart rate variability or just a marker of their overall stress the next day generally is better. That's good. The caveat with that being heat, just like anything else is a stressor. And if you get super crazy too soon, too hard,

it'll go the other way, right? Cause you are putting a stress into the system. So I usually tell people like, if you've got a sauna at the gym, you're probably not gonna be able to control the temperature. So just get in, breathe normal. Once it feels kind of hard, maybe go like a minute longer and then get out

and just keep track of your total time. If you're at home and you can control both temperature and time, I can get a little bit fancier and you can kind of, you know, alternate and play around with them. Total time depends. I mean, I have clients do 20 to 30 minutes, like two, three times a week. I think you're probably going to get most of the benefits. Yeah. But the caveat there is if you have zero experience doing a sauna, like five minutes is still going to be better, right? It may not be optimal, which I hate the word optimal, but you're probably moving in a better direction. As long as you don't go too hard too much, your stress levels are probably going to be fine. You want to be fancy and measure

heart rate variability the next day, see what's going on. Other than that, some people like using it before bed. It tends to be a little bit more relaxing. And then when you get out, you've got a drop in temperature, which can help the induction for sleep. Totally. I don't think the timing is super critical. If you're in there a long period of time, then yeah, making sure you stay hydrated is probably good. You get fancy and measure your body weight before and after sauna, see where you're at. I haven't seen any studies that looked at staying hydrated or not hydrated, but most people probably are not well hydrated. So anything you can do to drink a little bit more water, electrolytes, sodium is going to be beneficial. Yeah, I love all that.

And just to touch on the piece about helping you with your sleep, I tend to, when I use the sauna, go in the evening because I like to go when the local gym is a little bit less crowded. So I'll go at 738. And those nights, I almost always find my sleep to be extremely restful. I have almost no challenge getting to sleep, which I normally don't, but I definitely notice a reduction in perceived stress, a reduction in kind of perceived anxiety. It's a very calming effect for something that in that 15, 20 minute bout can be a little bit like, okay, this is not the most comfortable thing in the world. But for anybody who's listening, who's like finding, maybe looking for a way to work the sauna in, if you're also maybe struggling with your sleep hygiene and sleep quality, it might not be a bad idea to maybe head to the gym if they have one an hour before bed and then

take a quick rinse before you finally knock out. So that covers the hot stuff, I think, really, really well. And physiologically, before we transition to the cold stuff, we talked about these heat shock proteins being elicited by super hot temperatures and super cold temperatures. Are there any physiological, let's call them dichotomies that happen? For example, when you're hot, I know that blood vessels have a tendency to expand a little bit. And when you're cold, they have a tendency to contract a little bit. Are there any stark differences we should highlight about what happens when you're hot that don't happen when you're cold before we move on to the cold?

Hey guys, just wanted to take a quick second to say thanks so much for listening to the podcast. And if you're finding value, it would mean the world to me if you would share it on your social media. Simply screenshot whatever platform you're listening to and mean the world to me if you would share it on your social media. Simply screenshot whatever platform you're listening to and share the episode to your Instagram story or share it to Facebook. But be sure to tag me so I can say thanks and we can chat it up about what you liked and how I can continue to improve. Thanks so much for supporting the podcast and enjoy the rest of Yeah, that's a good question. And in general, if you heat vessels, they will expand. If you apply cold, they will constrict. The caveat to all of that just depends upon what vessels, where, length of time, etc. to the hierarchy, your brain is designed just to keep your body alive, right? So sometimes those mechanisms will be a little bit different. The big one related to people who train is the use of modalities immediately after training. And so it is true that if you get into cold water immersion,

especially up to your neck, or you immerse whatever body part you were training and you do it immediately after training and your goal is the maximum amount of hypertrophy. So muscle size possible. There's three to four studies now showing that that's probably not the best idea. Now the caveat with that is most of the studies you need to be in about 45 to 50 degree water for 10 to maybe 15 minutes. And they're all done immediately after. And so we don't know if you wait an hour or you wait two hours. We don't know if you go shorter and more extreme. We just don't have any data in those areas. Is that due to, and a lot, I've heard this before that anything that has an acute anti-inflammatory effect, even like an NSAID

can blunt the body's hypertrophy response. Is that what's happening there with the cold exposure? Yeah. So it's a good theory, but the data I've seen, like, so the, one of the main studies was done by, I think it was Dr. John peak. They looked at like a whole bunch of different markers of inflammation. And if I remember correctly, they didn't see any change. Okay. So I'm in the process of reviewing all the literature again for like the 800th time to look at specifically inflammation and cold. Yeah. I think at some point it will alter inflammation, but I think what's typically done with cold water immersion, I don't think is enough to change it.

In terms of NSAIDs, you are correct. So there's different types, right? You have your COX-1 and COX-2, but like over-the-counter NSAIDs such as Advil, et cetera, in mouse studies will change inflammation and will blunt some hypertrophy. In humans, kind of. The big caveat with that is depends on the dose, depends on how long. It's probably nothing that I would be super worried about.

It's probably nothing that I would be super worried about. And then if you go into older adults, ironically, NSAIDs appear to be mildly anabolic. Oh, wow. That's from Dr. Trappy's work. And the thought there is because older people have a little bit more higher levels of inflammation in the muscle, and we may be toning it down some that may actually be beneficial in that population. may be toning it down some that may actually be beneficial in that population where younger people yeah we may be toning it down but we're kind of getting out of this sort of goldilocks area where we want to be so NSAIDs do have some effect I think cold water may have some effect I'm not convinced by that data yet and in terms of exact mechanism, I don't think we really know yet. I spent forever like trying to figure out like, okay, well, what does that actually mean? Right. So let's say

my goal is I'm training for maximal hypertrophy and I'm a natural lifter and my maximal gains in optimistically is one pound of lean body mass per month. Right. And that's being overly optimistic. Yeah. If I do cold water immersion, like for 10 to 15 minutes, 50 degree water after every single session, like per pounds of lean body mass, like how much is that costing me? Yeah. Like half a pound, three quarters of a pound. And I don't know, because it's tough studies that were done on, we're looking at sometimes fiber growth, which you can't necessarily extract to whole body. There was a study that was done with DEXA, but if you run all the math, like you need a pretty significant swing and lean body mass to be even detected by DEXA.

It's probably still below our level of detection, but we do have the molecular studies, the fiber studies, cross-sectional area studies to show it is less. But in terms of real world, like practical numbers, I don't know how much less. It's interesting because one of the main things you'll often hear communicated by proponents of cold temperature exposure is the acute impact on inflammation. And you should do it because it's good for inflammation. And whether or not it impacts inflammation based on kind of what you were just saying, like, if it ain't going to impact my hypertrophy drastically, I don't care too much what it does for my inflammation because there might be some other benefits here. What are kind of the primary benefits? We'll stick

with cold water immersion and then we'll talk about cryotherapy and maybe finishing with the cold shower if there's anything there. what are the big reasons that somebody might want to incorporate cold water immersion? And then additionally, is there a difference between an ice bath and maybe the just general temperature of hose water? Yeah. Unfortunately, I think that most of the things that are claimed by cold water immersion are not true. Totally. I did a whole course on this. I spent for God knows how many months pulling as much of the research as I could.

And one of the things is, you know, cold water is amazing for fat loss, right? Because it increases the use of brown adipose tissue, right? Some tissue that has more mitochondria, these little furnaces, and it upregulates your body's production of energy. Therefore, you burn more calories and it's great for fat loss. It's awesome. If you look at the studies, probably not, right?

The amount you would have to be cold to have a significant effect on fat loss, you would be freaking miserable. Yeah. You have to be in cold water and probably shivering to have any effect. Or you have to sit in a room just above freezing and t-shirt and shorts for like 45 minutes every day. So is it true? Yes, it's true. but the thing that you would need to do to see a significant effect, probably not going to happen. Um, other things in terms of recovery from exercise,

maybe the data on that is pretty split. There's some data when mixed martial artists, the performance increased, there's mixed data on vertical jump performance speed and power the next day there's also a massive placebo effect right with athletes um if they feel a difference they're probably going to perform better yeah in that case if they're performing better then it's all the matter means like just go for it who cares yeah um i think there's some other benefits though that people don't talk about a lot yeah we don't have a lot of research on it, I think there's some other benefits though, that people don't talk about a lot. Yeah. We don't have a lot of research on it, but I think there is a huge metabolic effect that

we don't understand yet. Yeah. Um, so if you've ever done this, get into cold water, take your blood glucose beforehand, get into cold water. And then right as you come out, take your blood glucose again. I've had a couple of clients do this. I've done it myself multiple times. In general, my blood glucose will go from like 85 down into the 60s.

So just some type of massive. And this is with only like four minutes of like 45 degree cold water. Yeah. And for anybody who hasn't done cold water immersion, four minutes is a long, it's a long four minutes, especially the first time you do it. You'll be like, okay, how long have I been in here? 30 seconds. Oh my God.

You're kidding. If you had to guess mechanistically, is it like an upregulation of glute four? Is it something else? What do you think causes that acute drop in blood sugar? I don't know. I think it's literally almost as simple as the increased metabolic activity. Just using more glucose. Yeah. And I don't know why it has such an effect on blood glucose because blood glucose in general is very tightly regulated. So that's something that's super interesting.

Totally. And then I think the biggest benefit that doesn't get talked about a lot is, so when we had the lockdown, I had a freezer I converted to into cold water immersion. I'm like, well, great. I'm not traveling. I'm not speaking in any countries. I'm home for God knows how long. I took a year and a half and I'm like, I'll just do more aerobic training for a block. And then I'm going to do cold water immersion, like, you know, six out of seven days a week. And by the end of that year and a half, I started at 50 degrees for literally 30 seconds. At the end of the year and a half, I got down to, you know, the low forties, upper 39 for like five minutes, pretty easily. Pretty awesome.

So it took a long period of time. The interesting thing was, I thought for sure, after doing this almost every day for a year, that it would still, it would get a lot easier, right? Because if anyone's ever gotten into very cold water, it's just not fun. It just sucks, especially the first 30 seconds. It's miserable. You're trying to hold, catch your breath. You're hyperventilating.

You have lots of stress that's going on in your body. And what was fascinating is even at the end of the year and a half, I would stand next to the tub and I'm like, okay, here I go. I would, there'd always still be that hesitation. Like never once that I'd be like, dude, I'm so excited to get in here. Like right now, this is great. Um, but I think that's one of the benefits that's not talked about a lot, right? Cause to your, your lizard brain, the hard wired portion of your amygdala or whatever terms you want to use, limbic system. Reptilian brain. Being in cold water is something that could potentially really kill you. Now, granted, we have a very large buffer, so it's unlikely, but it's definitely possible. And then you can

use the professor, the prefrontal cortex, the new part of your brain to talk your lizard brain into doing it. We're in a safe environment. We're only here for a short period of time. Everything is controlled. We've done this every day for the past year and a half, nothing bad has happened. And so I think there's this kind of battle of the new versus old part of your brain. And I think the more you exercise that with something like cold water, that still is hard to do, but you can do it every day, right? Like you can only do so much hard exercise every day. You can only do so many hard things per day without, you know, increasing your risk of injury, overuse, everything else. So I think that's kind of a

useful component because you can train that to apply to the rest of your life. Totally. You know, okay, I'm going to do a little bit more exercise training or I'm going to park farther away with my car or I'm going to, you know, skip this meal or I'm going to eat this instead. I think the more you practice those skills, they do get a little bit easier. And that gives you a daily practice of choosing to do the hard thing. Yeah. And I think that's a good segue into cold showers and maybe we'll finish with cryo. Cold showers are, from a temperature perspective, not going to touch something like an ice bath. Because if you're doing cold water immersion in a freezer, a converted freezer, where you're doing

what a lot of people do where they go down to tractor supply and they get a trough and then they put ice in the trough and you fill the trough up, you're going to have much colder water than what's going to come out of your shower. But a lot of people that, well, one of the bigger crazes I'd say in the last five years is wake up, suck it up, take a cold shower, start your day with a cold shower or just take cold showers. One of my fantasy football group chat, like funny things that we say to each other when somebody is like, Oh my God, dude, I got killed on Monday night. Like this is such BS. I hate it. We'll just be like, take a cold shower, bud. See you next week. You know,

it's become almost a meme of mental toughness beyond the obvious difficulty of getting out of bed and exposing yourself to drenching your body in cold water. Are we able to get any of the benefits we get from the cold tubs, the dunks, the converted freezers from cold showers? And if so, could we use that to our advantage in an exercise context? I think it's useful. I mean, that's where I have most people start. I mean, I have a whole course that goes through this, but at the end of your shower, just turn it to cold for 10 seconds, right? I don't care how cold it gets. It's going to feel cold. And then, you know, do that for a week, right? Because part of it is because then people write back and they're like, oh, bro, but

like 10 seconds is not altering my physiology at all. Not that much, but it's still more than what you did before. But you're exercising those neural pathways to pick the hard thing to do. And over time, you do get a little bit of an adaptation to that. In terms of on the physiology side, water temp tends to be not nearly as cold. And the good and bad is that the water is moving over your skin. So if you've ever done this, if you've ever gotten into a super cold water immersion, but then you just sit there and you don't move, it doesn't feel as bad after a while. That's for two things. Like there is a little

bit of a numbing sensation to the skin, but you also build up what's called a boundary layer next to your skin. Your skin heats up that little thin layer of water. So the water right next to your skin isn't as cold. And as soon as you move around, you destroy that boundary layer and you can definitely feel a difference. Or if you get into a running stream or the water is moving, that feels way colder than just getting into a cold water immersion. So if we go back and we go, okay, from a physiology standpoint, what's actually going on, there's two sort of different responses. So when you get your skin gets blasted with cold water that is a massive sympathetic response right so

if you look at the literature on because at first i thought like well you know people die because of they just get too cold in the water and that's it and you look at the literature and you find that within the first like couple minutes many many people drown like if a plane goes down a cold lake or whatever and i like, how did they get hypothermia like so fast? And it turns out they didn't. What happened was they're not accustomed to it. They hit the water, their face hits the water and they have a gas reflex and they inhale their faces down in the water and they just inhaled water and filled their lungs full. So controlling that sort of gas reflex, I think is beneficial.

But again, that's a normal physiologic response because of the shock. It totally is. If you ever get in the cold shower, like if you haven't done it in a while, or you're doing it for the first time, the almost immediate thing you're going to experience is this need to take a deep breath and you just feel like you kind of can't. Yes. Yeah. And that's the gas reflex. So if you, we can kind of use this to our advantage too. So if you want to get crazy and you really want to upregulate yourself before a session in a perfect world, I would go extremely cold. I would just get into the cold, put my head under for maybe come back up, sit in there for maybe just till I got control of my breathing.

And then I would actually get out. Um, the longer you stay in, you may get a little bit more parasympathetic response. Uh, you will get redistribution of blood flow, right? Cause initially your body's going to go, Oh crap, we need to take all the blood and put it back to the core. And then after a while it goes, oh, we're okay. It's not that cold. Maybe let's redistribute, you know, some of that blood flow to other parts too. So how long you're in a different response. Last part on that too, is that different components that get hit with water have different effects so if you put your face in just a tub of water you have something called mammalian dive reflex and that's seen in free divers so free divers will get like these crazy low heart rates part of that's from training

but part of that is because their face and pressure changes, your body kind of perceives this as a threat. And so it's almost like kind of shutting down your system a little bit. Heart rate will drop down really low. So if you want to get crazy, my good buddy Cal Dietz has a protocol where you can use that to your advantage. And I've seen people go just massively parasympathetic for like one, two, sometimes three days afterwards. Wow.

So not something you want to use all the time or before a competition. But you can take advantage of that a little bit by sticking your face just in cold water itself. And that may have a different response than just getting your skin cold or sitting in the cold entirely. And last component, too, is if you have your hands or your feet or your face in, from a thermoregulatory standpoint, it's really different. So, again, my bias is if I want acclimation to cold and I want more than metabolic effects, I want the ability to stay there a little bit longer and make it semi-comfortable. I'll put on a thin layer of wetsuit booties and I'll leave my hands and my face out and I'll go all the way up to my chin. So I'm trying to get as much of my body in, but the places that are very sensitive to

heat loss or gain, I'm trying to protect a little bit on purpose. Yeah. I, I, my first exposure to any type of cold water immersion was for recovering and rehabilitating after some ligament damage from sports. And I had ruptured all of the lateral ligaments of my ankle playing basketball and also torn a ligament in my thumb. And the kind of just blanket high school basketball coach recommendation was, I don't know, just stick it in a bucket of ice. And I was like, okay, how bad could it possibly be to stick my hand or my foot in a bucket of ice? And to your point about eventually just getting to that place where I could do hard things, after two to three weeks of post-practice hand soaking or post-practice

foot soaking in a bucket of ice and water, I got better at it. But those areas were exceptionally sensitive to those cold temperatures to the point that I remember sitting there like almost on the verge of tears, wondering how it was possible for something to be so uncomfortable, just, just a hand or just a foot. It's pretty miserable. So, uh, transitioning now to kind of the last piece with the cold exposure stuff, the new kid on the block, of course, is cryotherapy. stuff. The new kid on the block, of course, is cryotherapy. Very expensive, probably of the things we've talked about today, even more so than red light therapy comes with a lot of sensationalized claims. We don't need to go into those claims. I'd like to just say, from an opportunity cost standpoint, knowing that it's relatively expensive to do, knowing we could replicate it probably much

fairly effectively with cold water exposure, is cryotherapy promising and is it worth doing? It's interesting. I mean, to me, if I had a choice, if someone gave me a cryo thing versus cold water immersion, I would actually still pick cold water immersion. So if we look at what's going on in cryo, right? So cryo is using air instead of water to basically displace temperature. Okay. Right. We know water is much, much, much, much better at doing that than air. So in order to use air, we have to use nitrogen and we have to get the air like ridiculously cold. And when we do that, we blast the skin and you do get kind of a sympathetic response. So I did it after doing a lot of cold water immersion and it was kind of like the people

at the place were kind of laughing at me because I'm like, I don't know, this doesn't seem that bad. They're like, what's wrong with you? This is supposed to be horrible. I just sit in cold tubs of water for several minutes a day. They're like, oh yeah, this probably isn't so bad then. But a benefit I do think of cryo is you still get a lot of that sympathetic upregulation. You do get a lot of changes in epinephrine, norepinephrine, dopamine. So from a, a feel good type standpoint, um, there's probably some pretty good benefits from it from I'm really changing my physiology and metabolism to whatever degree. I am not sold on that part yet. Yeah, that's fair. And so kind of if we've set a criteria for maybe using the sauna two to three times a week, 20, 30 minutes after your

workout, that seems like it's very practical, especially for people who are already in the rhythm of going to the gym. If somebody wants to then get the benefits of cold exposure, what's a practical way they might be able to include cold exposure using cold water immersion in cold showers? So a simple way is just at the end of your shower, turn it to 10 seconds of cold, right? I think that's pretty good. Yeah. If you have access to cold water immersion, maybe you've got one of these fancy tubs, you've converted a freezer. My bias is initially figure out and you're new to both, figure out which one you think may fit a little bit better. So if you're

like, ah, I like doing sauna better. Great. So if you imagine like a little barbell analogy, just work on adaptations to heat for four, six, eight weeks, right? Just like a train block, just like you would work on any other component, right? I'm going to do an aerobic block for eight weeks. So get really good at that and then put that on maintenance and then do progressively more cold, right? So maybe drop sauna to one or two times a week, opposite days, and then work on expanding your capacity to cold. Once you get that pretty good, now you can play around with, you know, contrast therapy going back and forth, or just kind of decide on what you want to do. So for me, like once I'm kind of adapted to

both, I'll probably be doing more cold again this winter. I'll do sauna after like a gym session on Monday. And right now I'm only in the gym once a week. So I converted my garage and then I'll do cold only after my aerobic sessions. So today I did an aerobic session on the rower and the bike. I do that Tuesday, Thursday, Saturday. There's some data, although it's preliminary and mechanistic, that cold water immersion after an aerobic session might be beneficial. There's a micro-regulation on PGC1-alpha and some other mechanisms. Plus, I know there is no negative

interference effect with aerobic training that I've seen. I might get a little bit of a muscle recovery possibly because I'm going to go lift again the next day. Yeah. So that's kind of what I would do. I love it. And so just kind of for everybody listening, there's definitely a benefit to exposing your body to extreme temperatures, whether that be very high temperatures or very low temperatures and including it as a almost post-workout, if you will. Your immediate post-workout thing is probably the most practical if you're already going to the gym.

But definitely something I think more people should start exposing themselves to, even if their physiological stuff wasn't there. I love the notion that it does just generally have the impact of it's going to stimulate the part of your brain, the regions of your brain that help you do things that kind of suck. And so that's a huge benefit in a world where we're kind of getting increasingly bad at doing things that suck as our brains are continuing to be

exposed to technology that makes things easier and instant. I love that. So Mike, where can everybody find you? You're such a resource or good resource for all things, physiology, training, aerobic training, anaerobic training, where can they find you? And you mentioned the course a couple of times, definitely let everybody know about that. Yeah. So the best place is probably miketnelson.com. There'll be a bunch of different places where you can opt on to the newsletter. Most of the data I have and information goes out via the newsletter, which I send six days a week. If you're interested in the course on cold plus the other three physiologic regulators or homeostatic regulators, it's PhysiologicFlexibility.com. Go to PhysiologicFlexibility.com.

You'll be able to get information on that course there. And then I also have a podcast, which is the Flex Diet Podcast. Just look on iTunes or whatever your favorite podcast player is and look up Flex Diet Podcast and you'll be able to find it. Awesome, Mike. Thanks a ton for coming on and we'll chat again soon. Thank you so much. Appreciate it. and we'll chat again soon. Thank you so much. Appreciate it. Thanks a ton for tuning in to this episode. I hope you enjoyed the conversation me and Dr. Mike just had

about the various different ways in which you can influence your physiology using temperature to improve your health, to improve your performance, and all of the other things that we discussed. Please give Mike a follow. You can find his information at the show notes linked below in this episode.

He's a awesome resource for whatever it is you're into, whether it's fitness, physiology, or nutrition. Mike is somebody who I think really has a lot of awesome things to offer. And as always, thank you so much for supporting the show, continuing to listen if you haven't subscribed or left me a five-star rating and review. That is the best way you can help me continue

to grow the podcast and reach more people. Thanks so much for tuning in and catch you on the next one.