Speaker A
Welcome to Huberman Lab Essentials, [music] where we revisit past episodes for the most potent and actionable science-based [music] tools for mental health, physical health, and performance.
Dr. Susanna Søberg explains how cold exposure activates the sympathetic nervous system and brown fat, boosting metabolism, with insights on cold shock, shivering and adaptation.
Key Takeaways
- Cold exposure should be uncomfortable enough to trigger a cold shock, but with regular practice the shock response diminishes.
- Brown fat activation via skin cold receptors and norepinephrine is a central mechanism for increased thermogenesis.
- Regular cold exposure, such as winter swimming, is associated with improved cardiovascular markers and insulin sensitivity.
- Brief, repeated exposures to cold and heat may produce health benefits, including increased brown fat and heat shock protein activity.
What the video covers
- Dr. Susanna Søberg discusses deliberate cold exposure and its effects on metabolic health, hosted by Andrew Huberman.
- Effective cold exposure should feel uncomfortable; the 'cold shock' reflects sympathetic nervous system activation and catecholamine release.
- Cold shock involves hyperventilation and the gasping reflex, which subside with repeated exposure and adaptation.
- Cold water immersion covers more skin cold receptors than a cold shower or cold wind, producing a stronger and faster response.
- Cold receptors signal the hypothalamus, releasing norepinephrine and activating brown fat, a key thermogenic tissue.
- Brown fat and skeletal muscle (via shivering) work together as thermogenic tissues to maintain body temperature.
- Multiple pathways link skin cold receptors to brown fat, suggesting an evolved homeostatic temperature regulation system.
- Shivering may release succinate that activates brown fat, though the speaker stresses avoiding hypothermia.
- Winter swimmers in Søberg's research showed lower blood pressure, lower resting heart rate, and improved insulin sensitivity.
- Repeated cold and heat exposure can grow brown fat and improve adaptation, with the body learning to stay warmer over time.
Chapters
- 00:00Introduction to Huberman Lab Essentials
- 01:00Guidelines for Cold Exposure and Cold Shock
- 04:10Cold Exposure Methods and Their Effects
- 08:20Brown Fat Activation Pathways
- 11:20Shivering, Muscles and Brown Fat
- 16:40Winter Swimming Study Findings
- 26:40Adaptation and Heat Exposure Benefits
- 36:40Closing Remarks
Full Transcript — Download SRT & Markdown
Speaker A
[music] I'm Andrew Huberman and I'm a professor of neurobiology and opthalmology at Stamford School of Medicine. And now for my discussion with Dr. Susanna Soberg. Dr. Susanna Soberg, welcome.
Speaker A
Thank you. So great to have you here. for many years have been interested in cold thermogenesis and you're bringing so much quality information about this area that for a long time I think was kind of niche and is now becoming more and more
Speaker A
mainstream. So my first question is there any way that we can start to gauge what is the best way to approach a deliberate cold exposure protocol? I mean should it feel uncomfortable? If the temperature is uh very cold and you
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feel that that you also feel very cold then you you should stay in the water a little bit longer. So I think it's just you should get uncomfortable cold. So as long as you get uncomfortable cold it's cold enough and you get this what we
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call the cold shock. So the cold sock is activation of your sympathetic nervous system and these activation of the the catacolamines.
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Does the shock mean that I'm having trouble controlling my breathing? Is that a good gauge? Yeah, you can say so because that's kind of like how we define it. So you hyperventilate so you have a faster um uh breathing rate. Um
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so that increases also because you activate your gasping reflex if you are new to this. Um but if you are adapted it it kind of subsides with time with adaptation. So what you can do is that you can train this cold exposure and you
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can kind of like get adapted to it so you don't have this hyperventilating response every time you go out in the cold water. So this is like building up your resilience, building up your adaptation. It's going to make this
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shock like subside a bit. So it's it's always harder in the beginning. But you should do hard things, right? You shouldn't think about cold water and cold water immersion as something that is comfortable. It should be hard because that's the point of it, right?
Speaker A
If you enjoy it, then yeah, then I'm I'm thinking something is wrong. It's not right. You should not enjoy it.
Speaker A
What are the differences in terms of impact short-term and perhaps even long term between cold showers, cold plunge to the neck, so that could be an ice water or just very cold water. Immersion with dunking one's head and then coming
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up because obviously people have to come up for air at some point. and then simply being outside on a cold day in shorts and a t-shirt or something of that sort.
Speaker A
So there are different outcomes um because there they are very different uh exposures of the cold to your cold receptors in your skin. So the more you can say you cover your body in the cold which you would do in cold water because
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there of course the molecules are closer to your skin you will have a more potent um activation of all your cold uh receptors in the skin. So that one will definitely activate your autonomous nervous system more and rapid compared
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to going out in a t-shirt in the cold wind just go for a walk. Um but that is also something that's going to activate your uh sympathetic nervous system meaning then that you will have an increase in norepinephrine uh and you
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will activate something called uh the the brown fat. So this is a healthy kind of fat tissue that we have in our body and when you activate that that's going to increase your metabolism. So it is kind of like our first responder in in
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the body to keep uh our temperature up. we have two tissues which can increase our uh thermogenesis. So the brown fat which is like always like temperature regulating our body and then we have uh the the muscles which will secondarily
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uh start to shiver and that's going to increase our um temperature in the body.
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But as soon as you go into a cold shower you will activate your brown fat also immediately. So it could be good also for increasing metabolism in theory because we haven't really any studies showing how much does it actually
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activate the brown fat. So if someone out there wants to do a study on [laughter] that would be great.
Speaker A
So it sounds like any form of cold to the skin that people register as what you called a cold shock or uncomfortable like h like this is kind of jarring activates the brown fat. Do we know what the pathway is from cold receptors on
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the skin to the brown fat? I mean, how does the brown fat know that we're cold?
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The cold receptors will send a signal to our temperature regulating center in in the brain, the hypothalamus, and that's going to be taking in this message. And we have so many cold receptors in the skin. So, it's going to be very fast as
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you can say if you immerse the body into cold water, this is going to be so rapid. Uh, so it will have a rapid increase in uh neurotransmitters in the brain. no adrenaline adrenaline and cortisol and uh which is not that much
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but it's but it's still there. So you have this increase in uh no adrenaline which will then immediately activate the brown fat. There's also a direct pathway from the co- receptors in the skin to the to the brown fat which really shows
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that if because of these different pathways it shows that that it could be that this tissue to keep us warm or developed in in our evolvement as humans to keep us warm and to save us whenever the temperature on our skin varies it
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just a little bit to keep us in that right homeostatic balance so we don't get hypothermic. IC but also so we don't get hyperothermic but because it seems that the brown fat is also activated when we get warmer in our skin. So it's
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also um maybe a temperature regulator in our in our body but the pathway is different. I think it's also a third pathway from directly from the muscles.
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So the brown fat is also activated even though the the muscles are starting to shiver. So there's a an extra pathway that way to keep our uh our temperature up. So muscles and brown fat are working together to to keep us warm so we don't
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Speaker A
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Speaker A
shiver. Um, I've heard that shiver causes the release of succinate, which then activates the brown fat. Is it known whether or not inducing shiver is important and when should pe people shiver?
Speaker A
You shouldn't be so afraid of shivering I think because the shivering as long as you don't get too hypothermic. So if you don't if you don't sit in the cold water for too long, something called the after drop is when your core temperature uh
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decreases even after you get out of the cold water. And it always does that um your body because it as soon as you get into the cold water h all the your blood vessels is going to constrict because
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you need to keep your blood in your core and and keep your vital organs warm. So as soon as you get up that those blood vessel will open again and the warm blood would flow out and get colder and
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then flow back again into the core and that's going to decrease the temperature in your core. Of course years ago Wimhof I heard him talk about the drop and I've heard colleagues of mine talk about the drop but that's the
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first time I've ever heard it explain clearly. Let me make sure I understand this. So um I get into cold water obviously I'm cold. Vessels constrict to keep blood near the center of my body, keep me alive. I get out. The warming up
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of my body allows those vessels and capillaries to dilate again. The blood goes out to the surface, but the surface is still cold and so that blood is cooled and then my core body temperature drops. And that's what you're referring
Speaker A
to as the drop and that's what induces shiver. Exactly. Great. And then am I right in thinking that then the shiver activates brown fat which then warms me up again?
Speaker A
Yes. Got it. That's why you should end on the cold. It's training. It's training for your for all your cells. is training for your muscles. It's training up your metabolism and that's going to increase your what's called the insulin
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sensitivity. So if you can like in your mind get used to the thought of shivering is just like when you go exercising in the training center and get that feeling of like oh this is tough now it hurts a little bit. Yeah
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it's going to hurt because that's what shivering also does but it's just a different way of training your cells in your body. It's going to create what is healthy stress. It's called homesis in the cells. And the more you expose your
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your muscle cells or your brown fat cells to these kind of like healthy stresses, exercise, cold and heat exposure, it's going to make them uh better at like activating and also at keeping you healthy. So as long as the
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the cells get exposed to this it's going to keep them on its toes you can say because it becomes more robust um increasing these heat shock proteins and cold shock proteins in the cells to um make you more robust for the next time
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and that is also what happens when you go to the training center and I keep like do drawing that parallel because people today know more about we know more about exercise and what that's is going to do to your muscles cells. But
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the same kind of like training is also what you do when you go out and and into the cold water and submerge into cold water because that is just your cold training center. You can say that and and also your heat training center going
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into the sauna because the cells are getting stronger with hormetic stress. So it's the same process just different practice.
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What are some of the other things that happen at the level of metabolism and brown fat in let's say the hours and um day after deliberate cold exposure?
Speaker A
Yeah. So what happens is that you you get adapted a little bit every time you go. So you will like exercise get a little bit stronger. So every time you go into the cold water for every time you will be more exposed to it. You will
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you will feel more comfortable in the cold. So you going to you're going to build your adaptation which happens on a metabolic level which is going to be the brown fat. So you will have more activation of your brown fat. the
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mitochondria in the the brown fat cells are going to be um you'll have more of those and they will be more efficient at heating you up because it expects the body expects you to to do this again so
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you are prepared. The capillaries in your skin is also be will also become better at like constricting so you will have a better shield of your body to uh prepare you for the next time. your stress response will also be uh subside
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a bit. So you will have a less increase of your catacolamines because of this activation of your uh brown fat or your muscles. You will have an increase in um uh in in your metabolism which will then make your insulin sensitivity uh better.
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And this is shown in in studies. For example, um there was this interesting study I found just before I I started my PhD which was from Gibbore Stormer um at L from 2016 where they measured insulin sensitivity in middle-aged men and women
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uh during one winter swimming season. During these four or five months they were winter swimming, they saw that they had a lower blood pressure after the season and they had a lower heart rate and they also saw that they have a
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better insulin sensitivity. And I think that is very interesting because if you can have a better insulin sensitivity, you can prevent lifestyle diseases and will lower blood pressure, which is a a very strong outcome also for telling how
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much inflammation you have in the body. And because they didn't measure uh brown fat, um I figured that it could be that was the missing link. That was the one of the explanations to why we see this um less inflammation in the body. So the
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longer outcomes, the long-term outcomes could be that you lower your blood pressure and you have a lower heart rate. Um you also um have a better insulin sensitivity and a better glucose balance. But that was shown that is
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shown in my study. Is it the case that as we're just moving around? I've heard of NEAT non exercise induced thermogenesis. So if we're just moving around um that we are activating brown fat or does there need to be this
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stressor? Does there need to be shiver and a cold stimulus or a heat stimulus to activate the brown fat?
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So cold is the most potent stressor activator of our brown fat because it's our temperature regulating organ in our body. So first responder to that. So actually just exposing yourself or or hand actually just to cold water. So
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studies have shown um that if you just put your hand in cold water, not that you're going to going to do that all day or or every day or anything, it's not it's it's not something you have to do,
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but it just shows that you can activate your brown fat just by getting a temperature change on your skin. People who works outside or move a lot or get out in and out of it like changing the temperature of their body all the time,
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they will have more brown fat and uh activating that is going to keep your metabolism higher and your insulin sensitivity. Studies have also shown this. So the brown fat can be activated as soon as you just change your
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temperature in the skin. So going outside in a t-shirt, wearing cooling vests, also studies have shown this for 10 days, it's going to also h grow your uh your brown fat. So you can get more brown fat if you expose yourself to the
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cold. You don't have to start in a cold uh shower. You don't have to start in a cold uh plunge if you're not really ready for that yet. But just exposing yourself to the cold wind has also shown
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to activate your brown fat. Or if you don't want to be like in this uh awake state um then you can also just sleep in the cold and you won't notice it that much maybe. But studies have shown that
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if you sleep in 19° C um then you will activate your brown fat and you will grow your brown fat so you have more of it. So this very nice studies um from Hansen ital from 2017 showed that a
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group of subjects who slept in a room at 24° and then they made this PET CT scannings to see how much brown fat do they have from the beginning so what we call baseline then they measured again after um a month of sleeping in 19° and
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they saw I think it's remarkable just one month at 19° sleeping there they had a duvet on And they were still had clothes on when they're sleeping.
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So they're under a cover under a duvet. Under under a duvet. Yeah. Yeah. Okay.
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The subjects were sleeping at 19 degrees for one month had increased his insulin sensitivity. The next month they slept at 24°. They measured this again and then [laughter] they had decreased actually a little bit. And then they slept at 27°. So quite warm room
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actually for for the fourth month. Um and they saw even less activation of the brown fat and also insulin sensitivity.
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So it seems that you can expose yourself and pretty rapidly the brown fat will respond to this because it's so sensitive to no adrenaline, right? So if you keep exposing yourself to a little bit of cold, you also get a little bit
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adapted to it. But that's because the brown fat um has grown these more mitochondria in the cells. So these small energy fabrics that's going to activate the cells and that's going to take up glucose and fat from the fatty
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acids from the bloodstream to keep uh the thermogenesis up and that's going to clear up some sugar and it's going to clear so in the in the bloodstream and some some fat as well. So the brown fat can in that way decrease uh our
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unhealthy fat which is the white fat. Um, and the white fat is what we don't want too much of, but we still need some. Of course, it's our energy storage. So, it's very important that it's there. We just don't need a lot of
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it. So, on our thighs and also around our inner organs, that's where it's it's located. So, if we can have activation of the brown fat just by going out in the cold and just by sleeping in a cold
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room or if you are have courage for it, you can go out and expose yourself in a cold plunge. Cold showers is also going to do the trick. So you can do different variations of this. Just exposing yourself to various temperatures is
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going to activate the brown fat because it was involved to keep us in a perfect homeostatic balance. Regarding temperature, so to keep us alive.
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I want to just get a clarification around this 19° C um room that they're sleeping in. So they're under a comforter, a duvet, and um and you mentioned they have clothes on. uh the room is 19 degrees C, but the
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temperature underneath their blanket might not be 19 degrees C. So presumably it's the cold on their face that's activating the increase in brown fat. Is that a reasonable uh expectation?
Speaker A
I think so. Yeah, because it's you have so many co-ceptors in your face. So it's actually it's enough and I think corresponds very well with the studies showing that you can activate the brown fat just by putting a hand into a a
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bucket of cold water. Uh, and I did this experiment myself in in my studies just to see how well did they uh respond to cold water. So it was four degrees Celsius cold water for 4 minutes and then I just measured blood pressure and
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heart rate to see do they have like an activation of this. I actually also measured the brown fat during this uh cold exposure for four minutes with an infrared thermography camera. Usually you cannot really see activation of your
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brown fat because it's located centrally in your around your central nervous system and the biggest depo as you mentioned before is up here under the the calvicular bones very close to the skin surface and because it's so close
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to the skin surface I could measure it with this very expensive camera. We measured the brown fat with this um and and I could see that after a few minutes that the activation was there an increase in temperature uh arose from
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that um activation just four minutes. So it's very rapid and I'm also measured in my study how deep was the brown fat under your skin. So it's very close to the surface which also shows that it it needs to be there to to heat you up and
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co-enzyme Q10 with your first AG1 subscription. I'd like to talk about your study. It explored not just cold but sauna and the co-use of cold and sauna as a way to probe metabolism and brown fat and other markers as well. If
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you could tell us about your study, what you did and what you discovered. When I started this research in 2016, I wanted to see if we can do like some kind of activity so we can have people move also or go and do something do
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something together or whatever. and and and the code uh made us think about well what about winter swimming? So we were just thinking okay winter swimmers um must in theory activate the brown fat right but we kind of didn't really know
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with was this kind of stressor too much too little or what will happen actually I read the literature I understood in theory what happens when you go into cold water but I completely understood it when I first tried it. It was really
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uncomfortable just doing it, but afterwards, as soon as I got up, I felt fantastic. And we went into the sauna and I did three rounds because I just loved it. I loved the feeling afterwards because you have all these
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neurotransmitters going in your brain and you feel more positive. You feel I feel invigorated. I had so much energy.
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Uh, and that like I I could totally see why people would do this to get energy throughout the day because I definitely had that. I didn't have to do three dips to to get that. I think one would be
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enough. I wanted to study the lowest dose you can say the lowest amount that we can get away with but still see health benefits. So I recruited winter swimmers who have been swimming for two to three seasons and they stayed only in
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the water for one to two minutes. So the cold subsides very quickly and you would get this activation of your rest and digest system which is your parasympatic nervous system. So the the other branch of your autonomous nervous system and
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you get that activation because you submerge into cold water and when you do that you have an activation of your diving response and you will slow down your um your oxygen consumption in your body and that is because the body tries
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to res preserve um oxygen so you will not get hypothermic too fast. So it's kind of like a survival system in your body. Um so this survival system is very um important for us of course so that will be activated and uh because of that
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you will after maybe 1 minute or so I'm I can't be precise on that because I maybe also varies a bit in in humans. So one to two minutes you will have full activation of the sympathetic nervous system but also the parasympathetic
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nervous system. So they do this two to three times per week and for each time they go each day they go uh they take three rounds uh of so three dips and two sauna sessions. So they start in the
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cold and they end in the cold water. What is the temperature of the sauna?
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Uh about 80° C. Then how long are they in the sauna? So they stayed there uh for 10 to 15 minutes. So depending on if they went two times per week or three times per week and we will talk about why it's
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important to end on cold the so-called sober principle. How cold was the water in this particular give an average because I realize it's outdoor winter swimming so it's going to vary.
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It's a very uncontrolled environment to do this kind of study then but I wanted to do something that was also very close to something people could do for free going out in nature and use that and also have the nature like it's a very
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healthy impact on us. it lowers our stress uh stress level as well. So, it's within the spectrum of very cold water.
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I would say from around 15 15° C and and down, but it was actually not colder than like 2 to 4° like in in on average when it was the coldest. So, it doesn't have to be that cold to be good enough
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and and enough to activate our metabolism. So what did you discover in terms of changes in brown fat, insulin resistance or insulin sensitivity rather and um metabolism?
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So what we we saw uh was we had this kind of different measures uh to see what's to try and unrell what what's actually going on when they are already adapted to the cold water compared to a control group who was matched on on
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various parameters. We did see that the winter swimmers had an increased insulin sensitivity, they produced less insulin on all the experimental days. So besides from just cooling them and measuring the brown fat on each of these cooling days,
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there were two cooling days and one thermomfortable day. Right? So I wanted to measure insulin when they just they were fasting, meaning that they hadn't eaten in uh eight hours before the study day. Um and they were completely laying
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still, not moving, just in a bed. Um and we measured insulin uh during the experimental day just to see how what level are they on and we could see that the the the winter swim had lower production of insulin and they also when
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they had an glucose drink. So we give them that to see if they to test before we enroll them in studies to see if they have diabetes for example and not knowing for example that that wouldn't that would like ruin maybe the study. So
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we test for that and see if they have like a normal curve. So what we did see in that was that the winter swimmers had a faster glucose clearance in the bloodstream. So after two hours uh we could see that they had a lower level
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and it went the curve went down faster than in the control group. So despite having lower insulin release, they have better blood glucose clearance, which is really what you want, what we all seek, right? You don't excessive insulin is
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bad. Insulin being a more or less a chaperone for blood glucose. How much cold exposure do people need? How much heat exposure do people need in order to extract these benefits?
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Yeah. So when we then calculated the numbers together, we can see that this was ended up being 11 minutes uh in total per week. uh so not in one session of course but they had two to three visits to the water and the sauna per
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week. So when we divide that out, it corresponds to being in cold water 1 to 2 minutes at a time, but also in the sauna 10 to 15 minutes at a time. And I think this is very like um also similar
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to what we see in other studies. Then I think it fits very well with what we call the homatic stress or healthy stress. So you expose the cells to this kind of like potent very stressful situation uh where they increase
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heatshock proteins in the cells and that will repair the cells. It shows that you don't have to expose yourself very much to the heat or very much actually to the cold to get this healthy benefits uh from going into cold going to heat and
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have healthy benefits on your cardiovascular system. So I think this is very important also message to to to get out that you don't have to go extreme. You don't have to swim for a half an hour in the cold water. You can
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go in the water for 1 to two minutes um per session but go up to 11 minutes per week in total. And for the sauna my study showed 57 minutes in total per week. And if we also then divide it out
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on these two to three days and two sessions each day correspond to 10 to 15 minutes. So it's a low threshold but I think it's it's good to have that to maybe we can aim for that if if people
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need to have something to to aim for. And I think and I think it's really good to have that because then you you don't have then you don't overdo it and if you overdo it you exhaust the cells and that
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addition to looking at regulation of blood sugar, round fat, metabolism and so on, were there any markers that you examined in the deliberate cold exposure group as compared to controls um that reveal to you that deliberate cold exposure could
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have additional benefits um say for uh immune system function um or for any function for that matter.
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Yeah. So for um we looked at in inflammation of course we measure the outcome of blood pressure and so on but we also measured the IL6 in the study just to see also an inflammatory anti-inflammatory marker. So IL is 6
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went up and it also follows with the IL is 10. So that is like also very known in the literature. So we measured that and I think it's very important to to think about the cold exposure and the
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heat exposure as something that then lowers the inflammation in the body and with if we can do that we will have an open door for um preventing lifestyle diseases right so for um type two diabetes but actually also for some
Speaker A
mental uh diseases as well so as known as depression and anxiety and also Alzheimer's disease which are all associated um in research also newer research showing that that inflammation increases the risk of depression, anxiety and Alzheimer's neurological diseases. So if we can decrease
Speaker A
inflammation in the body, we will decrease modern lifestyle diseases but also these increasing mental diseases that we see in these modern lifestyle times. I think it's very interesting that we can go out in nature and we can use these natural
Speaker A
stressors and it it I don't want to have it sound very romantic or anything. It's just it's just exposure to temperature actually just to cold or to heat that is going to twerk our body into a natural state again and and reset it where the
Speaker A
the homeostasis the balance has is lost a bit. So the body is going to repair itself in that way. And I think it's beautiful that we can do that just by changing the temperature of our body.
Speaker A
And although people are very scared of doing this because in our times we have been away from cold away from heat temperature for some for decades now um since we isolated our houses better and uh we are more sedentary. We also sit
Speaker A
more indoor. We don't move as much. So this very um modern sedentary lifestyle has made us more temperature comfortable just neutral. So no no wonder I mean that obesity is increasing. We don't expose oursel to the natural stasis that
Speaker A
we did earlier on um in in our involvement but al up until maybe the 70s the 60s where we started having more like uh comfortable lifestyles right and obesity increases in the in the 80s we can see that from statistics so I think
Speaker A
that if we can take in cold and heat it all increases the homatic stress in the body so it's doesn't have to be other than natural stresses to the body which then could keep us in that natural balance again.
Speaker A
Could we talk about what I refer to as the Soberg principle which is to end on cold in order to force your body to heat itself back up and thereby increase metabolism further still.
Speaker A
Yes. So when you when you end on the cold, you you force your body to heat up by itself and that will require that you activate you keep your brown fat activated and also your muscles which is a good thing. It's a good collaboration
Speaker A
to keep your thermogenesis up and that's like an an exercise even when you go home. So in that way you don't have to think about your cold exposure dipping in in your plunge uh or open sea or what
Speaker A
it is as just a an exercise that you do for one to two minutes and then it's over. If you end on the cold you have an exercise for your body going on for hours afterwards and that's not only on
Speaker A
your metabolism but it's also going to keep your neurotransmitters activated as well and increase that because your body is still cold. So you need that those neurotransmitters to activate the brown fat as well. So that's going to make
Speaker A
your brown fat cells more efficient and also your muscle cells more efficient. So increasing mitochondria in the cells which will then generate heat very fast.
Speaker A
So if you have done this for a few times, so maybe three, four, five times, you will notice a switch where you like feel that you get easily warmer and you can keep yourself warmer. And that is also what was shown in in my study is
Speaker A
that the the winter swimmers were physically uh warmer on the skin compared to the control group. So they they when they are out of the cold when they're out of the cold just relaxing and we tested this in in on the
Speaker A
days where they were sleeping in the lab. So we could see that they had a more activation of the brown fat a higher temperature. So probably because they also lose heat uh they have a higher heat loss to the body compared to
Speaker A
the control group because they have a more vascular skin uh because of the contrast of cold and heat. So they lose heat faster from the body during the day. But is that a bad thing? No, probably not because that's going to
Speaker A
keep your brown fat and your muscles a little bit activated. So you will have to it has to work to keep you warm.
Speaker A
Let's say somebody only had two days a week um to do deliberate cold exposure.
Speaker A
Maybe they don't have access to a sauna. Maybe they do. Would you suggest that they get in for one or two minutes, then get out, then get back in for another couple of minutes, then get out and call
Speaker A
that four, you know, four or five minutes um to try and get to that 11 minutes total per week.
Speaker A
Yeah. as definitely I think the the changes in temperature is what is strengthening your your cells in the body. So if you can do the short amount of uh exposure and then get out and get back in that is going to you can say um
Speaker A
um strengthen your cells because you are challenging them to to adapt to um changing temp temperatures. That's really what I keep hearing coming through in as you explain these data and all these um beautiful studies, yours and others, is that it's not really
Speaker A
about getting cold. It's about going from warm to cold and from cold to warm.
Speaker A
M I think if people can internalize that idea that they're going to um have a lot more flexibility, a lot more fun and and get a lot more benefit as opposed to thinking, okay, I need to get into X
Speaker A
degrees of water for X amount of time on X number of days, you know, in a very way all the time, how much and how cold and and I mean it's like it's just like well because we also don't have studies
Speaker A
showing exactly if you just keep 5° in your water and you do that for a month, then what happens we maybe in the future we will know much more about this and I'm I'm sure it's going to come and I
Speaker A
really hope so but I just think by logically changing that temperature up and down up and down and you also do that in your water it doesn't really it's not that important what temperature you you will have your water then then
Speaker A
just keep changing it going up and down it could be all up to 12° C you're going to activate your brown fat anyways I mean 12 uh 19° cold air is enough to activate your brown. So maybe we don't have to go as
Speaker A
cold as I think many people think. Um and putting ice even all the time. You don't have to. It's not I don't think it's necessary to to expose yourself to that cold uh temperature all the time.
Speaker A
Um but vary it a bit. Well, listen, I I want to really thank you for coming here today to talk about your work um and the incredible direction that it points to because I think that um you know, no one
Speaker A
study is definitive, but your study really again stands as a landmark in the landscape of exploring deliberate cold exposure and heat. So, first of all, I just want to thank you for doing the work that you've done and for the work
Speaker A
that you continue to do, which includes coming here today to to share knowledge with me and uh our audience. So, thank you ever so much.
Speaker A
I'm very grateful for being here. [music]
Topics:cold exposurebrown fatthermogenesiscold shockwinter swimmingmetabolic healthnorepinephrineshiveringinsulin sensitivityHuberman Lab
