Dr. Luke and his colleagues at Kickback Science have a habit of going deeper than the headline claims — reading primary sources, accounting for methodology, and presenting what the evidence actually shows rather than what we wish it would show.
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hello and welcome to Kickback science podcast I'm your host Dr Luke this podcast is your place to get the tools and knowledge necessary to navigate the world of Health and Wellness so kick back let's talk science this is good content this stuff has gone great we'll jump into it let's dive in let's do a little science I'm going nitty-gritty science right now I've been looking forward to this kind of going on a little bit of a tangent oh yeah that's right I forgot about that the information we discuss in this podcast is not meant to be taken as medical advice it is simply informative we're not affiliated with any organization or institution just a few guys talking science and having fun hell yeah welcome back guys good morning miss you guys oh good good morning you missed me too you miss I did miss you I did damn right you did so I just wanted to say uh that workout you got for me Reed kicking my butt that one took an hour to complete that yeah I was sitting there you say it's an hour workout I've been there for like an hour and a half plus okay but that's all right yeah you know using those rest times that he's got 30 seconds it's you know you say 30 seconds I might be pushing A little over 30 probably closer to I know it's tough I know I'm just like sore I'm sore which is impressive so for the listeners that don't know we've got something fun coming to you pretty soon in the near future and it is uh workout templates they're going to be customized workout templates that you're able to kind of shape to your goals your activity level and all that and Reed's got Joe starting his and sounds like it's working pretty darn good yeah yeah it is I I think it is we'll see
is we'll see we got to get some before and after pictures we should do that oh little photo shoot yeah a little photo shoot yeah Joe stri down to his skinnies snap some pics birthday suit we should have you do one of those like model struts and walk down back naked and on top of the workout Luke's putting together a little diet plan for me yeah so we're going to have um nutritional templates too for different goals whether it be build m lose weight lose body fat and you know how to follow a specific caloric inape protein targets and all that and uh I'm going to track my progress through all this so you can follow along my journey and uh join in if you want um yeah I think it's going to be fun you're a little lab rat I am we got to show that it works before we send it off to the public yeah you give me feeding times you just come over you're like all right you go put a little running wheel in his bedroom oh jeez all right welcome back everybody to another episode of Kickback science today we're going to be talking about all things cold exposure yes so uh Dr Luke let's kind of just get started on what cold exposure is well cold exposure I think is like the new trend like if you don't do it then you're not tough you're not cool yeah literally everyone seems to do it and it's it's one of those things where if you don't film yourself doing it were you really doing it dude that's so true you see every video is he has to film it's like all right just sit there like people will just get in the cold water and what's funny is they'll hold as steady as they can and try to like show you know I'm so adapted and calm and tough and there's actually something to this when you get into cold water and you're going to notice you get this like gasp reflex where takes your breath away initially it's called isn't it called
initially it's called isn't it called like the divers what is it called um well the mamalian dive reflex I see getting that so that's actually after you're in the water for a period of time we'll talk about the physiology of that but there are these reflexes of like cold shock yeah and so people will get into the water and over time you'll get adapted to this level of cold and so you won't get that cold shock quite as much and so these these people will like hop into these cold tubs and just be like look how calm I am I'm so tough but it's funny because they're actually not getting as much benefit when they're holding steady like that because your body temperature actually creates this thermic layer around you and you you can actually feel this next time you're in a a pool that's colder than really I mean any pool this is going to work for uh but when you get in any water that's colder than body temperature and you hold really steady for a while and then slowly move you'll notice all of a sudden the water feels colder as you start to move your limbs and it's because you get this thermic layer where the water that's right around your body noticed that before yeah the water that's right around your body is actually warmer when it's in contact with your skin and so next time you see someone pretending to be all tough cuz they hold steady you should comment and be like actually you're not that tough if you just slowly moved your limbs then you'd be tough so yeah you feel the if you're in the shower if you feel the water bouncing off your skin that's also a different temperature have you ever noticed that the so like like just hitting your skin and then heating up it is I swear to God I'm going to have to try that out I swear it is maybe I'm just like crazy but whatever I don't know I've never like checked like oh I wonder what the water temperature is it's bouncing off my skin so but the [Laughter] [Laughter] um now I lost my train of thought good yeah oh well so like on this like
yeah oh well so like on this like holding steady I just wanted to mention too like if you are trying to get the greatest benefit out of cold water and make sure that you keep getting this stress moving just slightly is going to be the best way to do that because you don't allow this thermic layer to develop around your skin and you don't want to move super fast and shiver because shivering actually produces heat on its own when you start shivering your body is actually Contracting your muscles to generate heat that's a method of heating yourself up so you don't want to like do that in the cold water sorry for the shaking sound for the people who are not watching video of this I am shivering U you you don't want to do that but just moving slightly in the cold and so we just dove into the science right away but I mean this it's funny how much this has blown up it seems oh yeah see Joe Rogan you got Kevin Hart yeah the coldest balls BS I love that's awesome everybody's doing like I see on my Instagram reals it's just people sitting in cold tubs or like my buddy's mom she actually in the metro area she' go in the lake in the winter time and just with a group of people and they just go all just standing there in the lake and this isn't like a polar plunge this is them just every morning they're just going doing this yeah they actually had an article about it in the paper it was crazy have you guys done cold water immersion like whether it be like cold tubs or or shower or anything you know when we had talk talked about cold water a while ago uh you mentioned to try it out and uh I didn't you didn't one of my old take back I did try it but man I hate cold water it's tough yeah well that's that's the reason that it actually has a lot of benefits is because of how uncomfortable it is see we're kind of we live in this like Society where it's easy for us to fall into the path of leas resistance you know you you don't have to do anything uncomfortable in your life if you don't want to you can sit at home and get one
want to you can sit at home and get one of those incline or beds that just reclines up so that you can eat and drink from your own bed never leave the house you can order door Dash your groceries you can order like groceries and a stuffed bald eagle to your front door you know there's literally no limits to what you can get delivered to you so you never have to have any discomfort and as humans naturally it's easy for us to follow this path of leas resistance so something that creates such a high level of stress it like cold water immersion it's hard to get people to do that when I've done it I've had to like really slowly turn it down and then so you slowly adapt yeah and then I get to that point where the breath gets taken away and I'm like yeah no I'm good you kind of start gasping yeah I do it for like a couple couple seconds good but I'm probably not getting any benefits from it well what's interesting with the research um is there's such a range of temperatures that are studied I mean some of these the the water can be as low as freezing and then some it it's a lot warmer and so there's not really this like temperature range or this specific temperature it's quite a range here here yeah because don't you just you want to start higher really because your body needs to adapt to it adapt otherwise you're just putting your body in shock which I know I get that's part of it it but if you go into too much shock like couldn't some [__] happen I mean you're you're not going to have any detrimental effects from just the initial shock itself it's when you stay in that c water for longer periods of time and we'll dive into that here in a second no pun intended um but yeah so like this this temperature range
yeah so like this this temperature range in the research you often see from 40 to 60 ° Fahrenheit which is from 5 to 15 ° C in that range uh that's what's most often studied that's a pretty wide range and and 60 ° Fahrenheit 15 degrees cels I mean that's that's cold and not comfortable but it's not freezing so you don't have to get into like like your friend's mom with like that that water is right at freezing you know uh you don't have to and if you do you have to change the time you're in these the the cold water there so if you're in a higher temperature you need to All Right video went out here so I had to get the video going so back to the uh temperature here um there's quite a wide range you know and you don't have to get into freezing cold water if you do get into freezing cold water water then you don't have to stay in there quite as long and so if you're in the warmer water you got to increase the temperature and it all comes down to this like stress induced stimulus and we're going to talk about this a lot in this podcast because we're going to talk about exercise a lot in other protocols that when you initiate this process referred to as hormesis where you have these acute stressors in acute meaning these temporary short-term stressors for your body when you have these over time your body starts to adapt to these stressors and so it's important to stress your body out more to get these adaptations and and so this you need to stay in the water for a certain amount of time to make it a stressful experience or like to force your body into this stress response if you hop into 60 ° water and then you keep doing you know 5 minutes for months at a time that water you're going to become adapted to which is a good thing you
adapted to which is a good thing you know your body is adapting to this stress and so you actually have to either increase the time increase the or increase decrease the temperature it's the same thing with exercise you know over time you have to increase you let's say resistance training weight sets or repetitions volume has to go up somehow uh if you don't you're going to be fully adapted to that and you're no longer going to get these benefits that that stressor will provide and so progression in cold water it goes down the same path as progression and exercise you know you kind of follow these same Concepts and uh you know before we dive so much into the protocols and stuff let's talk about like why the hell are people getting in cold water in the first place like where did this start yeah yeah where did it start cuz all of a sudden like you were saying Joe Rogan Kevin Hart like that [__] started popping up and then it was I mean honestly it's everywhere oh yeah people are buying those they got the little tubs tubs little like packages and Amazon you can buy for a cold tub it's they're just everywhere yeah it that industry is booming yeah like a trainer back in like 2015 16 that I worked with he used to do take cold showers every morning and we all thought he was crazy but like now it's really like caught on said started selling the tubs I know I was like whoa I should have started tub selling right there but yeah like what what's the craze behind why are people doing it so what's interesting about cold water is they um you know people have been doing this a lot like the Polar Plunge well the Polar Plunge was sorry you're probably not going there but I did yeah yeah the Polar Plunge is more of like one of those like charitable events yeah but it is the same thing yeah I mean doing a Polar Plunge the the benefits you're going to see but where you have seen cold water a lot is with athletes
seen cold water a lot is with athletes so this high-intensity activity where um after any sort of game practice a lot of athletes that are doing high volume work are hopping in the cold tub afterwards that's been happening for quite some time and it's because of this group of studies that have shown that cold water immersion reduces this delayed onset muscle soreness or what is referred to as Doms anyone who is involved in resistance training is familiar with that soreness Effect one day and then two days after your workout Joe's going through that right now you should right you could hop in some cold well we'll talk about you might not want to later yeah the the like so athletes hop in because you know you think about a a sport like let's say hockey for example you're going such high intensity for hours at a time and then you've got practice the next day you've got a game two days later and you've got to try to perform at this high level again uh that's going to take a toll on your body and if you feel sore you're not going to perform at that Optimum of a level and so there is a group of studies that has demonstrated that there is some significance here when you get into cold water there is a reduction in delayed onset muscle sess and this is actually true in terms of muscle damage itself and so it preserves this damage of the muscle and there's a reduction in inflammation in a variety of studies but this is actually interesting because some papers show that there's no effect on inflammatory markers and and when we throw around this inflammation word uh again you want to ask people when they say inflammation like what aspect of inflammation are you referring
aspect of inflammation are you referring to because inflammation is beneficial when you exercise you get a rise in inflammatory markers you you don't want to you know avoid that uh but in terms of recovery reducing inflammation is going to result in a reduction in feeling of soreness and so it you can can look at these inflammatory cyto kindes which we talked about in another podcast episode uh where these cyto kindes are these markers that are released to recruit different immune cells and to start this process of recovery and repair of the muscle those cyto kindes actually trigger these Sensory neurons these nerves that result in the feeling of pain and discomfort and such and so if you have a decrease in these cyto kindes your muscles aren't going to be quite as sore uh so there are a plenty of papers that show this reduction in inflammation now again that that area is kind of all over the place and some showing no change so the reason we see a reduction in delayed onset muscle soreness actually might not be due to this reduction in inflammation but either way it's happening people get into cold water after this level of exertion and they see that their feeling of soreness so perceived soreness how they actually feel is improved so they don't feel as sore and then they look at muscle damage and um the muscle is not quite as damaged if they do this now this is only true in these uh according to where we're at with the research right now there's a a recent metaanalysis that came out in 2022 that took 52 different studies this was done down in Australia Australia Adelaide actually shout out Ben tikle um and they they looked at 52 different papers with people who exercised and did cold water after they exercised for 15 minutes uh the temperature ranges were from 40 to all the way up to 68 ° fah um and they
all the way up to 68 ° fah um and they well the temperature or the time wasn't always 15 minutes that ranged to from 10 to 15 with if you're at a warmer temperature you're in there for longer but what they found is that it depended on the type of activity in terms of the benefits you get in delayed onset muscle soreness that um there was a Improvement in high-intensity exercise especially and so high intensity and then also endurance train you say high intensity are you talking like Sprints longdistance running CrossFit CrossFit lift and heavy weights so that's a good question so the high-intensity exercise included a a variety of things but really it was making sure that the participants or athletes were going to failure some level of fatigue uh so as opposed to you know just like a moderate walk jog type thing Sprint or Sprint till you're l or even resistance training multiple sets of multiple reps to failure that's high intensity until you can't lift the weight basically right and so this delayed onset muscle soreness seems to to apply to you know these high-intensity athletes and this is also true for endurance training so it helps the feeling of recovery here uh what's interesting though is there's another meta analysis that came out before this 2022 paper from Australia uh this one was uh the year before and they looked at the a variety of randomized controlled trials these are highly controlled studies uh that that tend to give us a little bit more of a of an Insight on causitive factors of the intervention being measured as opposed to to these cohort studies they're referred to where we observe populations and just you know see do they get diseases over time when we're assessing different
time when we're assessing different interventions so randomized controlled studies are much highly much more highly controlled and they tend to be a little bit more interesting in terms of findings so they in this paper they looked at a group of randomized control trials for cold IM cold water immersion and then also for sauna use so heat exposure it wasn't just saas it was you know some of it was like heating pads versus non-heating pads so they looked at ice versus heat or cold versus hot and they found and they were just looking at Doms we're still just talking about delayed onset muscle soreness here and they found that both heat and cold reduced delayed onset muscle soreness 24 hours after the workout but only heat was able to sustain that feeling of you know perceived muscle soreness and also muscle damage so actually heat is more Superior in terms of this delayed on set muscle sorness that you're going to get this is something that people don't really talk a ton about is like everyone's just hyping up the cold water cuz it's trendy right now and you can record a cool video yourself being tough but people fail to bring up that heat is probably a little bit better at this you know and and so I want to bring that up cuz we talk about sauna and all these impacts it has and and we're going to move through you say probably at 100 no I shouldn't say 100% it's 99% better well in in terms of recovery based on this group of studies it points to heat being Superior to cold uh but you know in in a research world and something that's hard to study it's hard to make these conclusions cuz you think about cold water and heat it's really hard to have a control group you know it's hard to conin someone that they're in cold water when they're not you know cuz you want to compare cold water versus you know the not cold water you can do that as a control but it helps
can do that as a control but it helps when you have like a placebo type trial where you can have people not know which group they're in you can't really blind these studies you know if you're cold or you're not cold and so it just makes them a little less controlled so the the data tend to be a little bit more variable there but still I mean you you do see these trends when you're looking at these systematic reviews and meta analyses that group all the research together they can point to these more causitive factors of what we're assessing uh and and so that's what we're seeing right now is heat seems to be superior if you're looking at trying to feel better 48 hours or longer than 24 hours after if you're doing a heavy workout and you want to feel better just tomorrow seems to not matter you can do cold or heat but if you're trying to prolong that heat seems to be superior does cold water have any cardiovascular benefits like the sauna does what's interesting so that that stuff hasn't been studied there are some papers showing um a reduction in blood pressure with certain populations like there's a a huge study that came out of Denmark where they looked at people who were swimming in cold water and that was just their way of training uh and and those people had a reduction in blood pressure now the problem is and we're going to talk about this study because probably like if you listen to the huberman podcast and uh he brings this up as being like this pillar of cold water research you know this groundbreaking study but I don't agree at all with that statement uh so we'll we'll dive into how that relates to other aspects but when you're looking at a population that's exercising we know exercise has these cardiovascular benefits you can't sit here and tell me that it's the the cold that's doing that I'm not going to buy it uh but there are you know papers suggesting a reduction in blood pressure we do not have the data suggesting these improved cardiovascular risk factors like we do
cardiovascular risk factors like we do with sauna though so doesn't seem to be that there's this cardiovascular benefit however think about it in terms of like what's actually happening when you get in cold water this cold shock response resembles on some level of similarity what we see with sauna and then also we see with exercise so if you listen to the sauna podcast you heard me relate the physiological outcomes that happen while you're in the sauna to what's happening in exercise now a similar set of effects is happening when you get into the cold you hop into the cold you know You' you're going to start increasing your respiratory rate this happens right away and then Joe you brought up this mamelon dive reflex that we'll talk about in a second but right away you're going to increase respiratory rate blood pressure is going to go up so your blood vessels constrict because they're trying to maintain heat so you've got these nerve receptors that On Your Skin Sense holy [__] it is freeing and we need to make sure that we don't get rid of any heat we don't want any blood going to the skin we don't want to be sweating we want to save that heat so it redirects all that blood flow to your core has all these vital organs that need to maintain a certain temperature we don't really care about our fingertips at this moment here and and so all the blood flow is getting redirected there now that constriction in blood flow and the increase in respiratory rate along with an increase in heart rate these things increase blood pressure and all these acute stressors again acute being the shortterm stress your body again is going to be like whoa what the heck just happened and how can I make it so next time I have this level of stress I don't freak out as much and that's the process of adaptation to these stressors so you see the heart becomes more efficient at pumping blood blood pressure drops you know you're going to become adapted to temperature you're going to Thermo regulate better and and so I bring that up to form a hypothesis of maybe there
up to form a hypothesis of maybe there is some cardiovascular benefit you're getting here now I don't know though we we don't know the answer to that question could be that it actually provides some level of risk we just don't know the answer to that question what we do know is that sauna does that though yeah okay yeah see yeah that'd be interesting to see a study like that that seees if you have that cardiovascular increase but yeah because there's a lot of studies on sauna but that'd be cool if they did a study on that as well yeah yeah I'd be curious to see it um let's talk about other forms of uh cold immersion uh cryotherapy like you'll see it like Antonio Brown did it but oh yeah he also lost like a toe I think AB what are the benefits of that compared to like think going nuts I maybe cry turns Antonio Brown you'll see it in those like therapy clinics pushing that but I don't know if there was a big craze compared to like the cold plunge or like in the cold tubs or cold showers this is kind of quieted down in my opinion I I only heard about it one time like a few years ago I had a buddy doing it he's like it's the best thing ever you just walk in this freezing cold room and you just standing there for a while and then get out you feel like a brand new baby well I mean that's essentially it you're trying to feel like a brand new baby so um it it people were latching on to this trend and then these cryo Chambers is what they are they essentially are pumping this freezing cold liquid nitrogen gas into these Chambers and so it it's actually like way way colder in terms of temperature it's from like negative 160 to 260 degrees Fahrenheit this liquid nitrogen gas getting pumped into the chambers uh but what's interesting is that subjectively meaning the perception
that subjectively meaning the perception of the person going into different cold subjectively people feel more uncomfortable in cold water versus cryo now I haven't actually done cry I had the opportunity to do it and I totally turned it down because I just like wasn't feeling like going in and I kind of wish I would have cuz now I'm kind of curious you do it when you're in Minnesota yeah basically hop outside it's basically negative 160 out right now and we walk out when you take your dog out in shorts and a t-shirt so you know yeah but so you're in this freezing cold liquid nitrogen chamber essentially but the gas versus liquid in terms of temperature gas isn't able to you know extract heat from your body as effectively and so it's it doesn't feel as cold uh but the typical Protocols are about 3 minutes you hop into these Chambers and a lot of like wellness centers were really pushing these like Oh Come hop in because of all these effects we see and there are some comparative studies looking at cryo versus cold water and it seems to be based on a majority of the data that cold water is far ior than cryo in terms of the benefits you're getting so I wouldn't say anyone should waste their money on going to a facility that has a cryo chamber when you could go get a bag of ice and pour it in your bathtub and fill it up with cold water or just as cold as you're setting on your bathtub or even a shower which we'll talk about here in a minute uh that's all free minus the water payments but you know you don't have to spend the money on cryo and so like one paper for example looked at um recovery from exercise induced muscle damage and cold water versus whole body cryo and they did single leg Ecentric exercise so it was five sets of 15 reps to fatigue and
five sets of 15 reps to fatigue and Centric can you just explain yeah yeah good question so uh when you contract muscle there's different ways of different types of muscle contraction you have shortening of the muscle which is what you often think of in terms of Contracting that's called concentric the shortening phase and then you have lengthening of the muscle so if you've ever seen people uh go slow on like the down phase of a lift that is them focusing on this Ecentric phase of the movement or the lengthening of the muscle which has been shown to induce more muscle damage so people that are really into hypertrophy based exercise growing muscle size will'll focus a lot on heavyweight Ecentric or lengthening muscle movement ments um and and really try to you know Harvest that effect of potentially having more muscle damage so when I say Ecentric here I'm talking about like inducing muscle damage in a lengthening phase of the repetition um and then isometric is just Contracting your muscle but not moving the joint itself uh so what they did is they had them do these um different strength or Ecentric exercises and then hopped in either cold water for 10 minutes or cryo after the session and then they did a variety of tests afterwards uh one of those being a counter movement jump assessing like power and they found that cold water was Superior than cryo in terms of counter movement and then they also found it was Superior in terms of muscle damage that was experienced as well from the Ecentric exercise so cold water seems to be better and then there's also this in paper uh This was done in 2018 with a group of marathon runners and these people where this was in London where they essentially had them go run a marathon and they checked all these Baseline metrics of um inflammation and
Baseline metrics of um inflammation and muscle damage and all this before they ran the marathon and then they did it again right after and then at 24 hours and 48 hours they also test tested things like strength and other assessments after the marathon was done to see what is the impact we have on cold water versus cryo and then they also had a placebo group which was super cool so they had this group of participants that they told about this juice that was shown to be anti-inflammatory and they're like oh yeah we're studying the anti-inflammatory effects of this juice so drink it 5 days before your Marathon so that they'd have this placebo effect of like oh I'm going to get decreased inflammation because you want to see is there Placebo impact here too but they actually just gave them a flavored water and it wasn't had no anti-inflammatory no antioxidants nothing super cool and so then they compared these three groups you have the cold water cryo and then that controlled juice drinking group that was your placebo group and they compared Muscle Recovery performance and inflammatory markers and they found that cryo is actually worse wow than Placebo than the juice even the placebo wa yeah so it it was worse it had a negative impact on muscle function and this feeling of soreness and so they actually felt more sore than the placebo group group feel a feeling companies out there are going to be coming after us you ruining our our business Well it Well the the I keep that's a doubt of my data when you start talking so then I have no idea what you guys are saying we'll get a I'll hear it when I listen back to the all good um but you know I don't want to say um cryo has a a negative impact because there are papers that show it is superior than cold water there's um one study that just showed these are middle
study that just showed these are middle and long distance Runners and they looked at after one workout what happens if you do cold water versus cryo two inflammatory markers and cryo was it was able to reduce inflammatory markers better than cold water but this wasn't consistent they measured a variety and some were higher in cold water so it kind of seems like a I don't know like this it tight of a study basically is what you're saying well I mean it was a good study but what I I point all this out to say when people act like cryo is superior to cold water that is absolutely not the case and you know there's papers suggest that cryo is actually worse than cold water at all these you know perceived soreness even exercise performance and inflammatory markers but you know and this comes back to this like when there's some causitive factor of some intervention you're going to tend to see consistent results especially at these uh meta analyses that are done the hard part with cold water and this goes this is true with sauna as well the hard part with these cohort observational St studies that are done is you know we we've talked about that but even the meta analyses that are done you in order to perform a accurate metaanalysis you want to look at making sure that the studies that are being done are among consistent populations you want to try to control for all these variables of you know are they comparing the same age groups same activity level same population in terms of all these other aspects diet does Diet have any absolutely yep and and so um in meta analyses they're able to do this really really well but if you don't have a lot of consistent studies then you don't have a lot of data to choose from you know so there's just not a lot of research on certain things this being one of them the cold water versus cryo uh but it it does seem that there's a pretty
there's a pretty clear group of research suggesting cryo is absolutely not more beneficial than cold water and and so Reed you asked about the different modalities of cold water there's also just shower in general and even just like being outside yeah cuz a lot of people don't have access to a cold tub those are pretty expensive so like most people have access to showers so like what's the protocol just take their old freezer and fill it up with water yeah yeah that works too you got to waterproof it though watch videos I thought about doing yeah you see people like coming in with sludgehammer the morning breaking the ice um yeah you can use a shower and there is a paper that looked at just cold showers and saw do you have the same like physiological adaptations that you do with cold water immersion and they tested a couple different protocols with a couple different shower temperatures and found that the coldest was at 10 ° which is 50 ° or 10 Dees Celsius 50 ° Fahrenheit which actually happens to be like the coldest you're going to get your shower anyways so they went to this um this temperature for that reason full blast yeah that's like absolutely as cold as you can get it most households are going to be right around that 50 some can't even get like you go to these hotter climate areas in summer freezing water when I'm doing it Minnesota Minnesota we we for sure get down to that 50 degree or 10 ° C Freez whereas like you go to like Florida or Texas or something and like in the summer it's harder to get the water temperature that cold but anyway they comp Ed the um essentially it was like 50 to 60 ° or 10 to 15 ° C water temperatures and 50 ° seem to have more significant benefits here but it did result in a similar level of adaptations now what's important to note when you're doing a shower protocol you don't have to put your head under the shower at all
to put your head under the shower at all and and the thing about it when you do cold water immersion I mean how many people on the videos do you see just like holding themselves underw these are all out immersions that are being studied yeah like you I mean people will like go under water come right back up but the benefits you're getting uh you don't have to put your head under at all and so when you're in the shower what you want to do is the the one area that will cause this reflex is your torso upper chest area uh that's going to like you notice that when you get into like a cold lake and you're walking in the shore at some point all get well it's that that's a different uh that's a different reflex there of like yeah feeling um feeling the little boys getting a little cold but you get that that gasp reflex as you start getting more towards your di Fram your chest and and so that's the area that you want to make sure get through yeah exactly you're keeping like your arms out of water so so you can do that in the shower and and what you want to do is just make sure the the water is hitting your chest for a period of time and then flip around make it hit your back and then keep doing that and switching and you can treat the protocol the same try three minutes on the chest switch do three minutes on the back and then end with like 30 seconds on each side or so yeah Gary Breco was saying your your best buddy uh Gary Brea was saying like two to six minutes is kind of where that sweet spot where you want to go where you see benefits at 2 minutes but like don't exceed six ah that yeah I feel like exceeding isn't going to matter cuz you're adapting the problem with well problem with Gary Brea is a lot of things but the problem with the two to six minute thing is like you're going to adapt to that and you're going to actually need to go above that six minutes okay you know think about it as what we were talking about before where it's going to not induce this stress response if you keep stopping at the same amount of time at some point you're going to have to if you want to continue
going to have to if you want to continue to see these adaptations you're going to have to get out of the shower and and hop in an ice bath because the shower can only get so cold and you don't want to sit in there for an hour maybe I mean go ahead yeah the 2 to six range is just a madeup number uh classic Gary but you um yeah I wouldn't stop at two but or stop at six now for the two minute thing it's totally going to be different hop in the shower and make sure you induce that gasp reflex where it takes your breath away you're going to feel that and then try to stay in there till where you can feel this level of and this is where you know we'll talk about the mamalian dive reflex where you get in this cold shock response and then your body actually tries to like preserve oxygen and they call it the dive reflex similar to when people are like diving underwater and cold or yeah diving in cold water and your respiratory rate is going to go down it kind of resembles like holding your breath in a way your blood pressure is going to drop your heart rate drops your parasympathetic nervous system gets really in control and that's your like rest and digest calm yourself down part of your nervous system there's a lot of theories suggesting that that's actually what happens after a period of time in cold and um Joe when you do this you'll notice Reed you you've probably noticed this so uh and this is what I shoot for getting in the cold and it happens a lot earlier but you you get in the cold you get this cold shock and then after for me it's right around like 30 seconds I can actually get pretty comfortable and it's not like you get acclimated yeah and then you actually start to calm yourself down and so that initial cold shock is what you have to kind of push through and that's the hardest part so if you're getting into like a cold water immersion protocol uh just try getting to that point where you can actually sustain it because once you get past that point I mean you can stay in there
that point I mean you can stay in there for quite a while um but you don't want to stay in there too long and if water is really cold so when you get into like the approaching freezing temperatures that water can reduce your body temperature pretty significantly if you stay in there for a long period of time I mean I wouldn't recommend anyone go in these freezing cold tubs for longer than a few minutes I mean definitely not longer yeah so you can get hypothermia where your body temperature when it drops induces these ectopic heart conditions which are essentially like these improper conduction in the heart that causes these irregular heart beats that can actually kill you and so you you definitely do not want to stay in there to that point and so if you're doing much Co let's say kind of just sorry uh let's say you've adapted you've slowly worked your way down to that freezing temperature are you more adapted at that point or does it really matter with it being free you will never be able to sit in that water and not have it have an impact on your body temperature um yeah I mean like some of the studies like one study when we talk about like the mental health side of things uh they used an hour they had cold water their participants sit in cold water for an hour but that water was 57 ° you know just short of 15 ° C and so you can sit in there for an hour but you're definitely not sitting in 32 to 40 some degrees at that time so yeah you definitely don't want to to induce hypothermia I wouldn't recommend people try to push passes Point yeah when you're in cold water um so can I touch on athletes again real quick yeah so
on athletes again real quick yeah so with them doing the cold water to reduce their uh soreness what about with um people who work out and bodybuilders and trying to gain muscle and then they hit that cold water yeah I was thinking the same thing cuz like I'm doing a really high protein diet I'm trying to build muscle like is this something that'll be beneficial for me to gain muscle or does it have a decree this is the part hey for all you people listening that just absolutely love cold water plug your ears for this okay because this is going to be controversial no this is not it's not controversial because the Reon I think is controversial no it's just like people have this thought of like cold water is going to cure cancer and it's going to solve all the world's problems just everyone hop in a cold tub so this is the area that people get a little bit like wait what no cold water only has benefits no risks um but there's a group sound just like that there's a group of papers showing this clear negative impact cold water has on muscle hypertrophy so muscle growth even strength adaptations and then also protein synthesis so when I say muscle growth when your muscles need to grow they'll go through protein synthesis which if you haven't yet listened to the protein episode where we break down really all the mechanisms of how that's happening but essentially your muscles need to take up amino acids from the blood and then use them to build back stronger and build back larger and cold water when done in combination with any strength training resistance training that's aimed at improving strength and muscle size has a negative impact on this wow and I say that's so that's not for me then I say that's controversial so we brought up this 2021 meta analysis when we were talking about
meta analysis when we were talking about uh people who were exercising and doing cold afterwards and how it improve delayed onset muscle soreness well what they also found is you know in this group of research things like one rep max were decreasing so people's strength adaptations were declining and this is pretty well represented in a couple different studies one of them being on protein synthesis and what happens to your muscle protein synthesis after you exercise if you go in the cold water so they took a group of young male adults and they had them do a single leg resistance training exercise to fatigue and did um it was like a 20 minute protocol that they did on one leg and then the other leg was not you know pushing weight at all and then they had them put the muscle or the lower body in cold water and then they came back another time and did it with the other leg and used room temperature water so you've got a cold water versus you know this control part and and they're their own control participants so it's the same person and they use different legs to make sure they're wasn't anything that happened with the previous resistance protocol on that one leg that impacted the other so it's a pretty tightly controlled study and then they had them drink this uh labeled protein drink that we talked a lot about in the protein podcast how you can actually label these amino acids so you can see when if they get absorbed into the bloodstream when you drink a protein shake and then you can see where they end up and so if you you know stab the muscle and take out this little chunk of the muscle the biopsies it's a brutal process I when I had these done a few times the muscle biopsies and that was in my leg too which is what happened in these participants and I was just crying like a baby it actually when I was doing research down in Australia and everyone was like laughing at me because I'm just like oh my God because you go into the muscle and
God because you go into the muscle and it literally is like a apple core process where they they put this um this thing into into the muscle that is when they twist it it will pull some of the muscle out and then you use a suction component to pull it out and I got to be on both sides so I've done this process and I've also had it done to me and it is it's more uncomfortable for some people like me is apparently I'm a baby but it is it's painful but anyway so they do this and then they can then assess how much of that protein is absorbed into the the muscle itself and they found that the cold water decreased the ability of the muscle to to absorb this protein and obviously that's going to have an impact on protein synthesis and that was actually demonstrated in another study too like what's actually happening within the muscle the cold water I didn't think it would have any effect that's just wild so basically if you're trying to build muscle you don't want to do any cold I mean that's what it's sounded like so then another group or another paper they assess kind of a similar approach here where they had a group of participants that were their own control subjects did lower body resistance training what happens with cold water versus just an active recovery so you know stretching just cooling down and what does cold water do to within the muscle cell itself and so when your muscle is damaged that is sensed by a variety of things within the muscle and it it your muscle has multiple nuclei within it it's the only multi-nucleated cell in the body and that just showcases how important your darn muscle is uh these nuclei are just kind of hanging out the nucleus of the cell is really what has this blueprint and ability to send out all these different proteins and make all these different components of the cell to make sure it survives and can grow and so the muscle just got a bunch of these they're referred to as satellite cells and they're just kind of hanging out waiting
they're just kind of hanging out waiting to see if anything's damaged that they just kind of like wake up and like whoa let's fix that and that initiates this protein synthesis process or it's involved in this protein synthesis process and they found that cold water immersion suppressed this activation of these satellite cells so it hindered that cell's ability to grow and then and it resulted in a decline in the size of the muscle now that wasn't tested in this study but this same group of authors did a kind of a a followup on this exact same mechanism so they found that there were these enzymes that were suppressed in terms of activating protein synthesis and then that satellite Cell Activation declined too so the muscle's ability to do this now this was just one acute bout of exercise what happens over time though and they found so what they did is they took a group of people and measured them over 12 weeks and had them either doing cold water after their resistance training sessions or active recovery and this training protocol was aimed at improving strength and increasing improving muscle size and they found that the participants doing cold water immersion had a decline in strength adaptations decline wow like they didn't even maintain I'm glad you just brought that up cuz I don't want to confuse people no they they still improved strength it doesn't diminish your ability to increase strength they still did it was just if they didn't do cold water they had a much greater increase in strength okay and so cold water just hindered the ability to improve strength but they still did have an increase and they they it was pretty significant too they they still did see quite a bit of strength it was just much more of an increase in that Recovery Group so if you're trying to build muscle just stay away from cold Merion yeah and they they actually have this interesting point at the end where it's a group of data suggesting okay we saw a decline in muscle cross-sectional
saw a decline in muscle cross-sectional area so they looked at the size of these muscle cells which is what grows that causes your muscles to look larger or to be larger I should say and so that was declined protein synthesis was declined and strength was declined so they say taken together these studies S suggest that individuals who use strength training to improve athletic performance recover from an injury or maintain their health should therefore reconsider whether to use cold water immersion as an adant to their training so if you fit amongst that group of people which I'd argue even if you don't I mean why would you ever want to impact your ability to to grow muscle I mean tune in to the protein podcast where I mean we touch on it and I would love to talk about the importance of muscle as a whole podcast itself with the cold water it's it's like a mental strengthening more than anything yeah I mean that's kind of what I'm getting from this is like it wakes you up in in the morning you're kind of pushing yourself through that stressor and in that way but as for athletic athletic abilities I would say it's negatively impacting you is that kind of true or is that a bad question I mean no that's that's a good question question no dumb question yeah it's a good question but I wouldn't say it it's necessarily true now because think about the athlet that do cold water immersion afterwards so that they can come out and perform uh the cold water did not have an impact on your ability to go through this high intensity performance after you know so like when you hop in a cold tub after a game you can still perform at that level and you're not as sore that improves inance stamina well and just ability to do the high-intensity exercise strength is diminished but a lot of athletes you
is diminished but a lot of athletes you know it's not they're relying on their capacity to perform at these high intensities relative to like get your heart rate up you know and and be able to sustain these long games and practices at high intensities that is not impaired that's improved and so it still serves a purpose here but they don't often during the season you don't see Athletes Training for muscle growth and strength adaptations your training actually shifts while you're in season to really not you're focusing more on specific movements and not working on or not inducing as much muscle damage in muscle growth that is not your goal during season that stuff comes off season and then you wouldn't incorporate cold water you wouldn't incorporate ice during that period of time so it still plays a role in athletes so these studies sound like they're doing cold water immersion like right as they're doing training is there any studies that show like cuz I take a shower in the morning but I don't out in the morning would that still decrease my muscle gains if I take if I did in the morning like or is it just like that short time period where your muscles are trying to rebuild I'm really glad you brought that up because the paper that looked at the satellite cell you know delaying the satellite Cell Activation that was still present after 24 hours they still saw this attenuation in activation of protein synthesis and building so even if you did a cold water immersion in the morning to wake yourself up and you did training in the evening it seems to be that there could still be this effect wow um this you know prolonged impact that cold water has so no I wouldn't say that you could just change the time I mean if you're not going to do if you're not going to lift for a couple days and go ahead and hop in the cold water but if your goals are strength and hypertrophy I'd stay out of the tub now I it's interesting though because I don't want to tell people to stay out of it because of this other really cool area I mean Joe brought up this like
area I mean Joe brought up this like wake up in the morning determination best cup of coffee I kept read reading that on Reddit like people are like this is the best cup of coffee I've ever had I'm so awake so alert yeah and and that like that plays a huge role in people's lives I mean again I don't ever want to tell someone that their goal shouldn't be preserving maintaining muscle mass or anything um as you go through life and have stressful things happening and you want to take advantage of cold water and the impact that it has on you know this alertness and also mood and things like depression and anxiety that area of research is really interesting uh so there's this really cool study I talked about where they had people sit in water for an hour it was 58 Dees and they had this group of people sit in there and they measured these circulating catacol amines and these catacol amines are dopamine norepinephrine and epinephrine and these catac colines play a role in reward hard mood that Feelgood determination and they measured them before they got in the cold water and then they looked at them right after and then for couple hours after that time point and they saw a 500% increase in epinephrine and a 250% increase in dopamine that's huge and I mean that level of dopamine increase is similar to what you see from like these dopaminergic medications that are used for or I I should say like drugs that increase dopamine that are so addictive and it's so like you hear people like say they're addicted to this cold water I don't buy that because of what I talked about at the beginning where the path to leaste resistance we will get addicted to things that are not uncomfortable for us and if you're doing cold water correctly it's going to be uncomfortable for you so it's hard to get yourself to do it so whether or not you can be addicted to that we don't
you can be addicted to that we don't know that I don't think so just because again it's difficult to initiate well but yeah I mean you do have this crazy post response of the dopamine and that Feelgood and that grit that drive that determination that is there it's hard to study that but this increase in these catac colomines that play a role in that point to okay there's a role here and they they found that these levels did drop after they got out of the water but they were still higher than Baseline after a couple hours there and so they remained elevated and there's another study this was a survey analysis of um de of depression symptoms this was done in 2020 and they randomized people into um they did this was actually with cryo oddly enough and they had people do 10 cryo sessions over the span of two weeks so it was five cow sessions um one week and then five the next week and then the other group was just a control they had the actually stand in the cryo chamber but they didn't drop the temperat they still dropped the temperature but it wasn't to induce the cold water or the cryo stimulus and so they had the two groups and then they looked at assessing depression symptoms there's a group of surveys that um are validated to actually assess somebody's level of depression you see these used in clinical settings they're accurate to determine if somebody does have depression and especially accurate to assess symptoms of depression but they're subjective meaning that the participants just kind of filling out how they feel at that day so take it with as much salt as you want uh but they did show that the cryo improved symptoms of depression so there's this impact of cold again probably on these catac colam Mees improving mood improving symptoms of depression there that area research is really cool and so when I push people away from
when I push people away from using cold you know if if you're relying on it for the mood aspects and you know you're you're not losing mus depend on what your goals are it does and because you're not losing the ability to grow muscle you're not losing the ability to gain strength you're just decreasing that you're attenuating it it's harder to grow mus harder to strength and so so it does still obviously serve a purpose and and yeah that's just a a fascinating area of research um so I was listening to Gary Brea's podcast and he was talking about Brown fat you go into it he's saying like you use these cold tubs and you'll lose Brown fat I I don't know a whole lot about Brown fat can you kind of dive into that yeah this is that that stupid swimming study from Denmark I shouldn't say this this is a great study uh I I'm really like I I do love the outcomes that were found I just hate it when people Mis represent what was actually found I I mean um and before I get into that I mean Gary Brea has just like this classic way of talking about things that he knows people are going to really tune into one of them being like weight loss and this cold water immersion is the best tool for weight loss that is just crazy um now Dr Luke loves Gary well cuz I saw him talking about cold water he starts talking about these like heat shock proteins like K you you have no idea what you're talking about maybe you're talking about here um but anyway we'll we'll save that for another time sorry not sorry Gary but so the brown adapost tissue this is a a common area of debate with cold water and people trying to use cold water as this like weight loss tool and it's like why are people trying to come up with these just like tactics of weight loss like get out there and move go do some freaking exercise stop trying to figure out this two-minute solution to your life's issues you know um not saying
life's issues you know um not saying that like weight loss is your life's issue fat loss improves Health but like people are always looking at ways to lose weight and trying to make it as simple as they can uh but in brown adapost tissue and cold water tends to to be that little Target there that people go after now brown adapost tissue your your body has different types of fat it's got white fat and beige fat or brown fat and atopos tis tissue is fat and brown adapost tissue the reason it has a beige brown color to it versus white fat is it has a lot of mitochondria mitochondria and inside of these cells there's this uh thing called myoglobin it's the the ability to bind oxygen and utilize it in the mitochondria it's why you see like red meat versus white meat it's relative to this myoglobin and mitochondria content and mitochondria are oh go back throw back to biology the PowerHouse of the cell right so so mitochondria produce a ton of energy they also have this ability to induce nonshivering thermogenesis so Thermo regulation regulating your body temperature without shivering and the way they do that is actually really cool there's two layers without getting too much into the weeds I'm going to get in the weeds guys I'm sorry so there's there's a couple layers of the mitochondria or membranes there's the outer in the inner membrane and the mitochondria is able to keep these different concentration levels from the inside membrane to the outside membrane and everything in nature follows this concentration gradient things want to go from high to low concentration high to low pressures that's why you you know things like wind you know moving from high to low pressure um when you again sorry bringing you down all this crazy process but anyway the mitochondria can keep the the high different concentrations on different
different concentrations on different parts of the membrane and that allows the mitochondria to prod produce energy because when it opens up a door on that membrane stuff goes funneling through from the outer to the inner membrane and that process there allows the mitochondria to produce energy it's like a a wind turbine or like one of those what are the things in the water why am I blanking on it that produce energy by moving like a turbine you know you see them at like dams dams have this underneath the dams that's why there's a dam it's higher pressure to low pressure yeah like I'm not a physics guy wind uh uh but essentially I mean that's now it's killing me I don't know all the physics people please comment in here and explain it but essentially like it's this same process happening in the mitochondria high to low pressure it's like this production of energy and energy is the production of heat and so when cold there's this protein called an uncoupling protein it's able to kind of open up that membrane and just allow these concentrating gradients or concentration gradients to do their thing and generate heat and raise body temperature so if you have more mitochondria you have a better capacity to increase body temperature and brown adapost tissu is involved with regulating body temperature now then everyone's like oh well if you can increase Brown adapost tissue you're increasing energy production you're increasing metabolic rate therefore you're going to lose weight and you don't have to exercise anymore uh and and that's where this area of debate comes in because there's this study with a group of people who they term them winter swimmers they go and swim in the water in Denmark that is freezing cold and then they were assessing so this population that does this habitually versus a group that does not do winter swimming and looking at what does cold exposure and sauna do to
what does cold exposure and sauna do to you know energy expenditure Brown atopos tissue and they looked at other metabolic metrics that uh we won't spend time talking about because it's not essentially as relevant here but they did find that the winter swimmers had an increase in brown adapost tissue activation and increase in metabolic or energy expenditure relative to the controls but the problem is they're swimming in the winter now this is so exercise is a great way to increase Brown adapost tissue activation increase energy expenditure so and also SAA does this too there's research showing just SAA alone increases Brown adapost tissue and now you've got three different things that we know increase Brown adapost tissue and you're studying a population and then ALS sudden every and and that's not what the researchers were telling us in this paper they were saying using sauna and cold water in Winter swimmers improves Brown adapost tissue that's what they found but then everyone's like cold water it was the Cold Water it was only the cold water nothing nothing matters with the sa nothing matters with the exercise cold water's going to help you lose weight it's like they're just trying to figure out how they could prove this point now it seems as though cuz cold water is Big right now they're like you know what let's just take that like you would say cherry pick the data yeah well and even if that was true whether or not that has an impact on total daily energy expenditure to the point where it's going to do anything for weight loss that is totally not evident as adults and especially as we age we start to lose Brown adapost tissue a child is really well able to Thermo regulate they have a lot of brown adapost tissue but as we age that declines and it makes up such a small portion of atopos tissue and contributes to such a small level of our total daily energy expenditure that even if you had this increase you likely wouldn't change
this increase you likely wouldn't change weight loss it would not move the needle there's a paper showing that increase in brown adapost tissue in uh individuals that were mid to late 30s only had a 20 calorie per day influence on energy expenditure that's doing nothing this paper here though they found like a range of like 500 to 1, 000 calories per day that's incredible but again they're exercising they're getting in the S they're getting in the cold like it's stop telling me it's the cold Gary and like I don't know what's what's actually really funny about this topic is so in one of his videos he says something like this is the best weight loss tool we have and he even says like and and what's interesting for the women listening is it's like G that's so sexist like you're saying that like women care about weight loss like I don't know this guy's crazy but anyway so he says that this is the number one weight loss tool here there's actually research to suggest well two interesting things one cold increases appetite so you if you look at people who do cold water immersion or are in colder climates they're increasing energy intake and it's pretty subconscious like they just feel hungry they're taking in more energy this has been studied cold induces an increase in energy intake so sorry Gary you might actually be gaining weight oh in cold water in addition to that there's papers comparing people that exercise in cold water versus people that exercise in body temperatured water they can have them do you know you've seen these like pools people could swim there's different ways to test like underwater exercise showing that cold water exercise reduced energy expenditure while you're going through this exercise protocol so there was a reduction in energy expenditure so if you're telling me that cold water immersion increases energy expenditure is going to lose fat like no it is not that is just not a tool okay maybe we'll see more papers come out and I feel like
see more papers come out and I feel like it would do the opposite your body's cold like I need more fat store like Hy yeah I'm to increase fat myself warm well I mean and I should point this out there is a cool area of research on Brown adapost tissue and the role it plays in metabolic Health it seems to be that people who have more larger quantities of brown adapost tissue are more metabolically healthy and you see that with people that are active throughout their life they don't lose as much Brown adapost tissue that's a pretty cool correlation there so I'm not saying Brown adapost tissue does nothing for your health it absolutely does but it's just like don't call this a weight loss tool because of brown atopos tissue this is like classic Gary Brea and other people on the internet that you hear just talk about like mitochondrial uncoupling and inflammation and all these big words that are like whoa this guy knows his stuff this is stupid um so another question I have I was listening to the hubman lab and they're talking about um the effects it has on the immune system like some people out I think it's either Denmark or like Norway where they leave their kids outside of like coffee shops to build up that immune system that's definitely Denmark Denmark they love the cold stuff but like my kids get sick every other week and like should I be incorporating my kids being outside in the cold more or like have you seen any research can't leave your kids outside I'll be watching them neighbors call cops like no you don't understand this is science they do in Denmark who's my new hippie neighbor um no so that um that is Denmark and I saw that uh so that the person who was on Andrew huberman's lab uh Dr s ber she is the one who brought that up she's the one who did this winter swimming study that was her study and so she came on to talk about it and you hear her talk about it like again like there's just the topic
like again like there's just the topic of the podcast is cold exposure so that's what Andrew huberman is probing on MH and so then a lot of people are listening to it thinking it's only the cold water immersion that's having these effects but if you listen to her talk about it she's explaining they looked at sauna they looked at exercise and and like going back to the study they address a lot of different differences in the control versus the intervention group one being there was a significantly larger amount of adapost tissue in the control participants white adapost tissue and if you have an increase in white adapost tissue that can impact the detection of brown adapost tissue so when they look at Brown adapost tissue in this study they looked at heat generation on the surface of the skin up near the chest that happens to be where we keep most of our Brown adapost tissue and they can see if it's activated based on heat production there if you have more adapost tissue your temperature is going to be if you have more white adapost tissue that temperature is going to drop um you could still have just as much Brown adapost tissue activation but it's harder to tell with the temperature on the surface of the skin in addition to that you're looking at a swimming population that has increased Thermo regulation from the muscle generation of heat from the muscle itself so if you're just looking at temperature how can you tell me it's brown adapost tissue it could also be muscle generated heat too and again that's just kind of poking holes in this and she addresses that she admits this stuff now to to come back to the inflammation thing um an immune function now the um leaving your kids outside no I'd say you can bring them in okay good there is the this inconsistent area of research so one the acute effects of cold are a little bit different than Theon than the chronic impacts of cold so chronic being long-term acute being just one bout of cold water reduces certain inflammatory markers that's also
certain inflammatory markers that's also another area that's not consistent you see some papers show it does some it doesn't but more often than not people suggest there's a reduction in inflammation if there's a reduction in these cyto kindes then there's going to be a reduction in immune cell Recruitment and activation and then you're actually decreasing your immune system activation that's an acute effect and so if you're you know looking to increase immune function you definitely don't want to hop in the cold or if you're like feeling sick you know um a colder environment there's actually research on like cold dry environments resulting in an increased susceptibility to viral and bacterial infections versus like warm humid climates uh but the interesting part of the research comes when we talk about chronic cold water immersion there are Trends to an increase in in immune function with an increase in cold exposure and I think Andrew huberman does a good job explaining the research but doesn't do a good job in explaining what a trend is so when he talks about immune function in chronic cold water immersion you'll notice him say a trend of an increase and then he says that is not significant now the way he says it people think when I say a trend and increase what are you taking what what do you take that as meaning it's trending upward yeah there's an increase right you're taking that as an increase right statistically though there is no difference when you hear someone say a trend it means we found no significance here but there was a difference in terms of just the raw numbers there but there was no statistical significance so therefore they cannot actually say cold water improved immune function they can say there was a trend toward an increase in immune function we have to do more
in immune function we have to do more research to see if there's any positive factor there uh but and so that's just a little pointer there when you hear people say Trends that's kind of this key word of and I do this like when I was talking about some of the research I was doing in my pH D like I If I ever said there was an increase uh but it wasn't significant you know you'd get called out like whoa then there wasn't an increase you could say there was a trend but it wasn't significant so you cannot say there was an increase so listen for those key words when you're hearing people interpret data this isn't me saying Andrew huberman has some you know initiative to try to misw things intentionally which maybe he does maybe he's trying to make people think things about cold that aren't necessarily true but I don't think so I think it's just the way that people who are not familiar with conducting and interpreting research and how statistical analyses work uh if you don't have that level of familiarity you're not going to know what he's saying there uh but that's what a trend is and so I don't know I mean maybe there's this impact of chronic we'll see as it plays out but right now you it doesn't seem to be that there's this clear increase in immune function that thing in Denmark she was saying that that was just like historically done you know people just that's like one of those Traditions that just happens cuz people are like maybe they just want peace and quiet Cofe or something garlic on your nose sinus infections put onions in your socks you scare vampires it's just these things that get into Traditions I'm not saying it doesn't happen it's just it's not we don't have that answer so basically I got from this podcast is like if you're trying to gain muscle stay away from this but if you're trying to improve mood this would be a good um good thing to do I I would agree that's that's really the main points I grab from yeah I mean you you did say you can still gain but it's very it's sign you said
gain but it's very it's sign you said significantly less than not doing cold water yeah so like the ability to go through that protein synthesis and grow muscles was significantly a 10 Ed which means delayed and then decreased in cold water versus not cold water yeah really that's really what what it comes down to I don't do it anyway that's what your goal you should try it I mean it it's actually really cool um I've tried it I just I don't enjy you got to get past that I I don't do it because I like to focus on strength and and hypertrophy mainly hypertrophy uh but there was a period of time like on and off where I would do it and I had an easier time doing it in the shower because I could I took shower every day I could always incorporate it into yeah it's more accessible but what was interesting is when you get past that shock Point um that's always kind of cool you know I had something I was thinking about a little bit ago um you ever been outside in the Heat and you take a ice cold rag and put it on your neck and it the water on your neck and it drips down your spine I get that same take your breath away feeling is there something to say that instead of just whole body immersion could you just focus on the neck and spine I don't know this just a thought ahead so that um gasping reflex is because of that those peripheral nerves that sense temperature that communicate it to this area in your hypothalamus that's job is we're going to regulate our core body temperature and so if you feel something cold it's similar to feeling something hot like you get that reflex that you know you could have the cold and well you actually you don't get that reflex unless it's like up at the diaphragm or above you wouldn't have that with the toes You' pull your toe
that with the toes You' pull your toe away but the Gasping reflex is is not happening there but you that's what you're experiencing now to answer the question of like could you just put it on your back in that cold water uh shower protocol study they did both chest and upper back those were the only areas so like that would just be your focus is making sure it's on your upper body I wouldn't say just doing the back um you're going to get more benefit off chest and back and so if people are like trying to come up with a protocol um you don't have to get an ice bath you know you don't need ice you could do this in the shower uh it seems to be that 3 minutes on the front 3 minutes on the back have it as cold as the shower can get cuz that's right around that 50 ° uh you'll work your way into it you don't have to start at that point just start until you feel the breath get taken away and then try to get to that point past that shock process where you're calming yourself down because then you'll just be able to stay in there a l long longer people will hop out early on because of that shock process but you will get past that the first time you do it your body's going to calm itself down you can't just stay in this level of shock um your body's not going to do that and then um if you're wanting to move past the the shower into a cold tub to drop the temperature you could toss some ice in there you can even wait for it to like heat up a little bit so it's not like right at that freezing cold level and just start with a few minutes I wouldn't go any longer than 10 minutes here I mean you it you're not like a lot of of these papers use 10 to 15 minutes but in the really cold temperatures they actually have them doing it in multiple bouts so hopping in for you know two minutes coming out hopping back in for two minutes coming out and not staying in there for that long period of time again you don't want to induce hypothermia uh but play around
to induce hypothermia uh but play around with it and then you just want to progress to induce that stress response and and pay attention to how your body's adapting but again if you're not if you're training for hypertrophy strength then use the sa because again the sauna has after your workout I mean there's really no benefit that cold has that SAA doesn't and SAA has even more benefits there you know and saa's just not as like sexy online you know people aren't taking pictures of them sweating with random other people in the sauna and posting it online it's just people want to c one except for Jo R yeah well any other uh thoughts here that was awesome yeah I learned so much today yeah yeah that was thanks Dr Luke you're welcome guys I'm gonna miss you guys miss you too thanks for listening everybody should we go hop in cold tub no let's get Joe in a cold tub again for tuning in to the kickback science podcast we love talking science with all of you and if you feel the same you can support us by subscribing hitting that like button and giving us a follow on our social media Pages don't forget you can submit questions through our website and in the comments section of all our social media have a good one everyone he
Transcript auto-generated by YouTube. Verbatim — duplicates intentionally preserved.
This 84-minute conversation on cold water immersion is one of the more thorough lay-science treatments of the topic available. It covers everything from the acute physiological response to the long-term adaptation pathways, without the promotional framing that characterizes much of the cold plunge content ecosystem.
200–300% Norepinephrine increase from cold water immersion 50–59°F Optimal temperature range for hormetic cold exposure 2–5 min Target duration for maximum adaptive benefit
cold water immersion for health triggers a cascade of immediate physiological responses. Within seconds, cutaneous blood vessels constrict dramatically as blood is shunted away from the periphery toward the core. Heart rate initially spikes — the cold shock response — before stabilizing as the dive reflex partially activates.
Breathing is involuntary and rapid in the first seconds. This is not a character failing; it is a deeply conserved survival response. The key skill that cold practice develops is the ability to override this initial respiratory chaos — to find a slow, controlled breath — which in turn signals safety to the nervous system and allows the parasympathetic branch to begin its work.
Norepinephrine floods the system. Endorphins release. Cortisol initially rises, then falls below baseline post-immersion. The full hormonal picture of a cold water immersion session takes several hours to resolve.
The cold works through hormesis — the paradoxical phenomenon where a stressor in controlled doses produces beneficial adaptation, while the same stressor in excessive doses causes harm. The dose makes the medicine. The dose also makes the poison.
For cold water immersion, the hormetic window is relatively well-defined: temperatures between 50–59°F, durations of two to five minutes, frequency of three to five times per week. Within this window, the body's adaptive response outpaces the stress response. Outside it — particularly with extended immersion in very cold water — the risk of genuine hypothermia and cardiovascular strain increases without proportional benefit.
Understanding hormesis reframes the cold practice entirely. The goal is not to endure the most extreme cold. The goal is to reliably trigger the adaptive response — and then allow recovery to occur.
The most consistently replicated finding in cold immersion research is the norepinephrine response. A single two-to-four-minute cold immersion session can produce a 200–300% increase in norepinephrine — a neurotransmitter and hormone central to focus, attention, mood, and what is sometimes called "a sense of agency."
The effect persists for three to six hours post-immersion. This is a large, durable signal. For individuals dealing with low motivation, depressive mood, or difficulty with focus, a morning cold practice offers a pharmacologically meaningful intervention — without pharmacology.
Dr. Luke's team notes that this is one area where the subjective reports from cold practitioners closely align with the measured biology. People say they feel sharper, more driven, and more emotionally stable after cold. The norepinephrine data explains why.
The most contested area of cold immersion science involves its interaction with strength training adaptation. Cold suppresses the inflammatory response that follows resistance exercise — and that inflammation is part of the signal that drives muscle protein synthesis and hypertrophy.
The finding that concerns strength athletes: cold applied immediately post-training can blunt gains over a training cycle. The practical concern is real, but the magnitude is sometimes overstated. The impact appears most significant with very cold water (under 50°F) applied within 30 minutes of training, performed consistently over months.
The pragmatic solution is straightforward: separate cold from training by several hours, or reserve cold for non-training days. The recovery benefits of cold — reduced soreness, accelerated readiness — can be preserved while avoiding the adaptation trade-off.
The goal of cold practice is not to endure the most extreme cold. It is to reliably trigger the adaptive response — then allow recovery.
The norepinephrine data is one of the most compelling single-mechanism arguments for cold water immersion as a mental health tool. — Kickback Science
Hormesis requires a window. Too little cold produces no adaptation. Too much cold produces harm. The skill is finding the dose. — Dr. Luke
Target the hormetic window: 50–59°F, two to five minutes, three to five times per week. This range produces adaptation without excessive stress.
Expect a 200–300% norepinephrine increase after your session — and a three-to-six-hour window of enhanced focus and mood. Time your plunge to use that window productively.
Separate cold plunge from strength training by at least four hours, or use cold only on recovery days, to avoid blunting hypertrophy signals.
