Supercharge Exercise Performance & Recovery with Cooling

00:00:00.160 | welcome to huberman lab essentials where we revisit past episodes for the most potent and

00:00:05.440 | actionable science-based tools for mental health physical health and performance

00:00:10.080 | i'm andrew huberman and i'm a professor of neurobiology and ophthalmology

00:00:15.840 | at stanford school of medicine this podcast is separate from my teaching and research roles at

00:00:20.560 | stanford it is however part of my desire and effort to bring you zero cost to consumer

00:00:25.280 | information about science and science related tools to the general public we just closed out

00:00:30.320 | the episodes on hormones now we are going to talk about how to optimize physical performance and skill

00:00:36.720 | learning there are so many variables to physical performance and we can manage physical performance

00:00:43.040 | and skill learning from a variety of contexts i made just a short list of some of the things that come

00:00:48.560 | to mind that can powerfully impact physical performance and skill learning some of them

00:00:53.520 | are what i would consider foundational they allow you to show up with your current ability and if you

00:00:59.840 | were to disrupt those you would perform less well so things like getting a good night's sleep things

00:01:06.400 | like being properly hydrated things like being well nourished there are supplements there are drugs there

00:01:12.480 | are different ways to breathe there are so many tools related to mindset visualization it's just a vast

00:01:19.040 | space but it's not infinite and there are a few things in the list of things that can impact and even

00:01:27.520 | optimize physical performance and skill learning that have an outsized effect that any of you can use

00:01:34.240 | so today we are going to focus on what i believe to be one of the most powerful tools to improve physical

00:01:42.560 | physical performance and skill learning and recovery we'll talk about about why that's important and

00:01:48.880 | that's temperature believe it or not temperature is the most powerful variable for improving physical

00:01:56.880 | performance and for recovery there are two aspects to temperature of course there's heat and there's cold

00:02:04.800 | we are mainly going to focus on cold as a way to buffer heat we're going to talk about cold from the

00:02:11.840 | standpoint of thermal physiology this is a literature that's rich in scientific information that goes back

00:02:20.160 | very deep into the last century where physiologists and neuroscientists figured out that there are different

00:02:26.640 | compartments in your body that heat and cool you differently and that you can leverage those in order

00:02:32.960 | to double even triple or quadruple your work output both strength repetitions and endurance so this is not weak

00:02:40.480 | sauce as they say this is the stuff that can really shift the needle quite a bit and it's not just about

00:02:47.280 | performing well once it's about being able to perform well and recover from that performance so that you

00:02:53.120 | do even better when you're not incorporating these tools on days where for instance you can't access

00:02:59.360 | cold or an ice pack or an ice bath or things of that sort let's start by talking about temperature

00:03:05.200 | how does temperature impact the body and its ability to perform including learn new skills so

00:03:12.640 | everyone probably remembers or has at least heard of the word homeostasis right that the body wants to

00:03:19.600 | remain in a particular range of temperatures that it doesn't like to be too hot or too cold heating up

00:03:26.560 | too much is just plain bad it's not just bad for physical performance it's bad for all tissue health

00:03:34.000 | cells stop functioning they stop being able to generate energy they stop being able to digest things you stop

00:03:41.600 | being able to think and eventually those cells start dying off entirely now you don't want to become

00:03:48.560 | hypothermic either you can die from hypothermia just like you can die from hyperthermia however that you have

00:03:55.520 | a lot more range to be cold than you do to be too warm okay and in general the idea is to keep the body and brain in a

00:04:05.600 | a particular range but anytime we do anything our body temperature can shift so for instance

00:04:12.640 | if you were to stand next to a campfire where you were outside on a hot day various things would happen

00:04:19.360 | to dump heat from your body now what are those things well there are a huge category of them but the

00:04:25.680 | simplest way to think about this process is that when we get cold we tend to vasoconstrict we tend to our blood

00:04:33.520 | vessels tend to constrict and we tend to push energy toward the core of our body to preserve our core

00:04:40.000 | organs okay so our periphery our hands and our feet and our toes and our legs become colder and our core

00:04:46.800 | therefore can maintain blood to that area and we are insulating our core conversely when we heat up our

00:04:54.800 | blood vessels vasodilate they expand a bit and more blood flows to our periphery and more blood can move

00:05:02.480 | throughout the body generally and we will perspire we will sweat water will actually get pulled out of

00:05:09.200 | the blood to some extent moved up through sweat glands and will be brought to the skin surface so that

00:05:15.200 | it can be dumped we are dumping heat so it's very important that if you want to understand how you can

00:05:23.360 | leverage temperature for physical performance you have to understand that you have vasoconstriction to

00:05:29.040 | conserve heat vasodilation to dump heat that you have sweating to dump heat and you have conservation of

00:05:34.240 | fluids in order to preserve heat that's the most important thing in terms of understanding the

00:05:41.680 | mechanisms of maintaining and dumping heat and now the most important thing to understand is that if you

00:05:47.760 | get too hot your ability to contract your muscles stops okay i'm going to repeat this because it's

00:05:54.480 | vitally important atp is involved in the process of generating muscle contractions the range of

00:06:02.080 | temperatures within which atp can function and muscles can contract is very narrow somewhere around

00:06:08.800 | 39 or 40 degrees celsius it drops off and you will not be able to generate more contractions

00:06:15.520 | now it's pretty hot but it can that temperature can be generated locally really fast put simply if you

00:06:22.240 | get too hot you stop exercising you may not even realize it but your will to exercise further your ability to push

00:06:30.400 | harder is entirely dependent on the heat of the muscle both locally and your whole system if you can keep

00:06:37.680 | temperature in range however in a proper range you will be able to do more work you will be able to create

00:06:45.760 | greater output you'll be able to lift more weight more sets more reps and you'll be able to run further

00:06:52.000 | now there are data that i'm going to talk about in a little bit that are absolutely striking that

00:06:57.200 | underscore that statement there are data from my colleague craig heller's lab in the department of

00:07:01.040 | biology at stanford many if not all the nfl teams are now using this technology as well as military uses it

00:07:08.160 | and not just for sports performance but also firefighters construction workers other professions where

00:07:15.280 | elevated heat becomes a barrier to performance and you can leverage this to really improve your

00:07:20.960 | workouts so how do you dump heat in order to perform longer safely well in order to understand that you

00:07:29.200 | have to understand that the body has three main compartments for regulating temperature okay we don't

00:07:34.800 | just have a center and a periphery we have three main compartments and there's one compartment in

00:07:39.600 | particular that all of you or most all of you i have to assume have and if you can understand how that

00:07:47.360 | works you can do tremendous things for your performance and for your recovery one is your core we already

00:07:53.920 | talked about that your core organs your heart your lungs your pancreas your liver the core of your body

00:08:01.120 | the other is the other is your periphery which are obviously your arms and your legs and your feet and

00:08:06.320 | your hands but then there's a third component which is there are three locations on your body that are far

00:08:14.160 | better at passing heat out of the body and bringing cool into the body such that you can heat up or cool your

00:08:22.960 | body everywhere very quickly those three areas are your face the palms of your hands and the bottoms of your

00:08:32.640 | feet now the skin on your hands and on the bottoms of your feet and to some extent on your face are called

00:08:38.800 | glabrous skin that's g-l-a-b-o-r-o-u-s glabrous skin and what's special about those areas of your body and the

00:08:49.680 | glabrous skin is that the arrangement of vasculature of blood vessels capillaries and arteries that serve

00:08:58.320 | those regions is very different than it is elsewhere in your body in these three regions of your hands

00:09:05.600 | your face and the bottoms of your feet we have what are called avas avas are a very special pattern of

00:09:14.080 | vasculature avas are arteriovenous astomosis a-r-t-e-r-i-o arteriovenous v-e-n-o-u-s

00:09:26.080 | arteriovenous anastomosis a-n-a-s-t-o-m-o-s-e-s arteriovenous astomosis okay you want to know about

00:09:38.400 | arteriovenous astomosis trust me avas are direct connections between the small arteries and the

00:09:44.320 | small veins they bypass the capillaries to some extent they are little short vessel segments they

00:09:51.680 | have a big large inner diameter and they have this very thick muscular wall and they get input from what

00:09:59.600 | are called adrenergic neurons they get input from neurons that release norepinephrine and epinephrine

00:10:05.680 | which allows them to contract or dilate now there's some rules of physics that talk about

00:10:11.440 | how the radius of a pipe and small changes in the radius of a pipe leads to massive increases in the

00:10:19.680 | rate and amount of stuff that can flow through that pipe okay that's a rule of physics that says essentially

00:10:26.400 | that uh the radius is uh proportional to the amount of stuff that can flow through something to the

00:10:32.480 | fourth power what you need to know even if you don't want to know any of the underlying physics is that

00:10:37.200 | these avas allow more heat to leave the body more quickly and more cool to enter the body more quickly

00:10:46.240 | than other venous arterial capillary beds throughout the body in other words you can heat up best at the

00:10:54.880 | face the palms and the bottoms of the feet and you can cool down best at the face the palms and the

00:11:01.680 | bottoms of the feet than you can anywhere else on your body these three compartments of your body palms

00:11:06.960 | bottoms of the feet and face are your best leverage points for manipulating temperature to vastly improve

00:11:14.720 | physical performance so what craig and his colleagues did really illustrates perfectly what these body

00:11:20.960 | surfaces can do and why they were studying overheating in athletes and in military and in construction workers

00:11:31.680 | and trying to prevent it what they essentially found was that cooling the palms palmer cooling

00:11:38.240 | allowed people athletes and recreational athletes to run much further to lift more weight

00:11:47.520 | and to do more sets and reps to a absolutely staggering degree

00:11:54.640 | let's talk for a second a bit more about why we stop why we shut off effort when we get too hot when

00:12:04.080 | muscle heats up enzymes start getting disrupted and atp and muscles can't work so well and those muscles

00:12:12.880 | can't contract the enzyme that's involved here is something called pyruvate kinase and pyruvate kinase

00:12:21.200 | is essentially a rate limiting step it's a critical step that you can't bypass if you want muscles

00:12:27.600 | to contract and it's very temperature sensitive

00:12:30.000 | therefore if you can keep temperature lower you can do more work per unit time you can do more pull-ups

00:12:40.320 | what they essentially did is they brought someone into their laboratory

00:12:43.040 | who could do 10 pull-ups on the first set and they were able to get 10 rest two or three minutes get

00:12:50.320 | another 10 rest two or three minutes and if you've ever tried this what you find is that you start

00:12:53.920 | dropping to eight seven six etc now the person might not necessarily feel like they're overheating but

00:13:00.960 | the muscle is heating up then with their knowledge that these avas that these that these portals in the palms

00:13:10.880 | are a great way to both heat the body but also to dump heat from the body they used a device and i'll talk about

00:13:18.960 | what you can do at home but a device where they had people hold on to what was essentially

00:13:24.000 | a cold tube now this is crucial the tube can't be so cold that it causes vasoconstriction because then

00:13:32.720 | the cold won't pass from the tube to the hand and to the core but if it's the right temperature it's neither

00:13:40.720 | too hot nor too cold that cool from the cold tube passes into the hand these so-called palmer regions

00:13:49.520 | and then cools the core and in theory by lowering body temperature would allow the person or the athlete

00:13:56.960 | to do more work and indeed that's what they saw the actual data the specific data showed that subjects could

00:14:04.560 | do at least the subjects they worked with on their first day with no cooling about a hundred pull-ups

00:14:09.600 | the time frame that they had then they came back and did the cooling they did it the very next day

00:14:18.640 | which if you've ever trained a muscle the very next day typically you wouldn't do as well in its training

00:14:24.880 | if it took any damage from the previous sessions or you at least do as well but you probably wouldn't

00:14:29.280 | do what they then observed which was they started cooling after every other set the person would just

00:14:34.400 | hold the cold tube cool down the body after every other set rest everything else was kept the same

00:14:40.240 | and they found that they went to 180 pull-ups which is incredible it's a near doubling now you may be

00:14:48.240 | asking what about endurance with endurance similar increases have been shown and the way that they would

00:14:56.720 | do those tests are a little bit different and they also point to a really important mechanism of why we stop

00:15:02.880 | doing work at all when we perceive that we are putting in too much effort so it gets right to the heart of

00:15:09.200 | the relationship between temperature and muscles and your willpower those are directly related your

00:15:15.600 | body heat and your willpower are linked in a physiological way okay so let's talk about willpower

00:15:21.360 | and heat and how heat shuts you down in other words if you are cool if your body temperature is in a

00:15:28.560 | particular range not only can you go further but you will go further if you want to

00:15:34.160 | said differently if you heat up too much you will stop or you will die

00:15:40.960 | but there's a reflex that relates the body to the brain

00:15:46.480 | and the brain to the body that shuts off our effort when we get too hot

00:15:52.000 | so what craig and his colleagues and now others have done is to do a test in the laboratory where

00:15:57.200 | rather than ask people to run outside until they absolutely don't want to run anymore

00:16:01.920 | you put them on a treadmill and you set the speed okay so they have to keep up with the treadmill and at

00:16:07.920 | some point they quit and you take groups and you do those in different temperature environments so some

00:16:18.000 | people are running in a nice chilly laboratory they get their heart rate up so they get into a steady state

00:16:24.240 | cadence or rhythm and their heart is beating it more or less a steady state people will continue

00:16:30.000 | at that temperature and at that heart rate unless you start turning up the temperature in the room

00:16:35.840 | and at some point they will stop and they'll stop much earlier when it gets hot because of something

00:16:42.400 | called cardiac drift okay so let's say i'm running and i'm running at a steady cadence on this treadmill

00:16:48.960 | and my heart rate is 85 beats per minute or 100 beats per minute doesn't matter let's say 100 just for

00:16:53.520 | sake of example well just making the room hotter is going to increase my heart rate further even though

00:17:00.720 | i'm at the same output and the brain does a computation it somehow figures out that there's a heat component

00:17:09.200 | that's increasing heart rate and there's an effort component from running that's driving heart rate

00:17:14.320 | and if the heat component and the and the heart rate output from the effort get to hit a certain threshold

00:17:21.040 | i stop increasing temperature increases the rate of quitting in part not entirely but in part because

00:17:29.360 | of this thing called cardiac drift heat increases heart rate effort increases heart rate at a steady

00:17:36.640 | effort you'll have a steady heart rate if you increase the heat in the environment that you're

00:17:41.440 | engaging in that steady heart rate your heart rate will now go up due to cardiac drift and you will quit

00:17:48.240 | okay so heller and colleagues have done experiments where they do palmer cooling under these environments

00:17:54.880 | and that's wonderful because not only does it enable people to go further and faster

00:18:02.080 | for much longer that's been shown statistically significant every time

00:18:07.920 | but it also protects the brain and body against hyperthermia overheating coma nerve injury nerve death

00:18:15.760 | and actual death okay so you can see why this is such a valuable tool so how can you start to incorporate

00:18:22.400 | this well first of all i always get asked how cold should the water be should it be ice water should it be

00:18:30.240 | very cold water the answer is no if you want to experience some of this effect without a device

00:18:38.080 | one thing you could do would be for instance to do i don't know i'll use the the the gym or the treadmill

00:18:43.360 | as an example you could do your maximum number of pull-ups stop and then you could actually put your

00:18:49.200 | hands into or on the surface of a sink that is presumably stopped up with cool water so not ice water not

00:19:00.800 | freezing cold but cool water slightly cooler than body temperature before you started training would be a

00:19:08.800 | good place to start you do that for 10 to 30 seconds then you could go back and do your next set you

00:19:15.440 | would repeat the cooling you would want to extend the amount of cooling somewhat so you might want to do

00:19:19.760 | that for 30 seconds to a minute this is not going to be perfect you're going to have to play with how

00:19:24.560 | cold to make it in order to get the optimal effect but you ought to see an effect nonetheless the same is

00:19:31.200 | true if you're running and you're fatiguing obviously you don't want to become hyperthermic cooling the

00:19:37.040 | hands or the bottoms of your feet or the face would be the ideal way to dump heat in order to be able to

00:19:42.880 | generate more output now the face is something that we haven't talked a lot about everything i've told

00:19:49.360 | you up until now also says that if you are somebody who tends to get cold when you are outside say in

00:19:54.560 | the winter or even in the fall you tend to run cold warming your face is going to be the most important

00:20:00.560 | thing that you can do now you understand the principle and the locations at which to deliver heat and cold

00:20:06.480 | so let's say that you are out for a run and you want to incorporate this cooling mechanism i talked to

00:20:12.640 | craig about this i said what would be the kind of uh uh poor person's approach to this one he said well

00:20:17.520 | you you could take a uh a frozen uh juice can if you have one of those or a very cold can of soda and

00:20:25.040 | you would want to pass it back and forth between your two hands the reason the passing back and forth is

00:20:31.040 | really important is because you again you don't want to be so cold that you constrict those venous portals

00:20:37.920 | that will allow cold to go into the body now there are certainly people that are working on

00:20:44.080 | bike handles and that can actually cool the hands here's what you don't want to do you don't want to

00:20:50.720 | cool the core if you want to cool the body right if it's a very hot day and you're going to train

00:20:57.440 | getting into an ice bath first sure it will it will cool you down but that's not going to be

00:21:03.680 | as effective as cooling the palms the bottoms of the feet and the face the one that i've tried

00:21:09.600 | because in anticipation of this episode was the dips where then i would cool my hands i actually

00:21:15.760 | decided to cool the bottoms of my feet as well because it just feels good and it's particularly hot out

00:21:19.440 | lately so no shoes or socks on put my feet into uh the bottoms of my feet just kind of hovering

00:21:25.840 | about a centimeter or two below the surface of a bucket of water that was just slightly it felt cool

00:21:31.360 | slightly cooler than um body temperature um or so it just basically what came out of the spigot after i

00:21:36.960 | let it run for a little bit and indeed i saw a 60 increase in the number of dips i can do in a single

00:21:43.440 | session so it's actually a quite significant effect and you don't have to be perfectly precise in order to do it

00:21:49.280 | so up until now we've been talking about how to use cold during a workout in order to improve

00:21:54.560 | performance now i want to talk about the use of temperature in particular cold to improve the speed

00:22:00.640 | and the depth of recovery recovery is obviously vital right during a weight training session or during

00:22:08.880 | an endurance session that's just the stimulus for getting better the next time and if you don't recover

00:22:14.080 | you not only won't get better but you'll get worse there's a lot of interest in the use of cold in

00:22:21.040 | order to improve recovery in the short term we see this and probably the best example of this would be

00:22:27.600 | fighters in combat sports between rounds or athletes during uh in between quarters or half time

00:22:35.600 | that's one form of recovery the ability to go back into the sport very soon on an order of minutes

00:22:41.360 | anywhere from like one minute in between rounds in typical combat sports or several minutes at a

00:22:46.480 | half time etc and then of course there's recovery that occurs from session to session so outside of

00:22:52.960 | the game or the match or the or the exercise um session and many people are now relying on things

00:23:00.800 | like cryotherapy which requires a lot of expensive equipment big you know um liquid nitrogen driven uh

00:23:07.280 | machine that those aren't so common for most people are accessible for most people but a lot of people

00:23:12.000 | are using cold baths or ice baths or cold showers and again that's not going to optimize recovery in

00:23:18.400 | fact it's going to have an additional effect that is going to potentially block the training stimulus when

00:23:24.720 | you get into an ice bath you are indeed blocking some of the inflammation that occurs because of the training

00:23:30.880 | you get into the training session but in doing so you also are blocking pathways such as mTOR mammalian

00:23:37.600 | target a rapamycin which are involved in the adaptation for a muscle to become stronger or bigger put simply

00:23:44.400 | covering the body in cold or immersing the body in cold after training can short circuit or prevent the

00:23:52.480 | hypertrophy or muscle growth response it has other effects that can be positive right it can induce

00:23:58.240 | thermogenesis etc it can reduce inflammation but it can prevent some of the positive effects of exercise

00:24:05.280 | now it hasn't been examined so much for endurance work but let's say you come back from a round of

00:24:11.120 | endurance work a run or a bike or a swim getting into a cool bath or cooling the the palms the bombs of

00:24:19.280 | the feet of the face in my opinion based on the science would be better than completely immersing the body

00:24:25.520 | in the ice bath if you can cool the body back to its resting temperature for a and by resting temperature

00:24:33.360 | i mean within the range that you would see at any time of waking day but not in exercise if you can do

00:24:39.600 | that the sooner you can do that after a workout the sooner that the muscle will recover that the tendons

00:24:45.440 | will recover and that the person you can get back into more endurance training more weight training

00:24:50.640 | etc so cold actually can be a very powerful tool for recovery but to maximize return to baseline levels

00:24:58.160 | of temperature just simply cooling the entire body by jumping into an ice bath or a cold shower is not the

00:25:03.680 | best way to go you really want to rely on one of these three glabrous skin portals of the palms the bottoms of

00:25:09.360 | the feet of the feet or the face one of the more commonly used compounds that's sold over the counter

00:25:15.360 | are non-steroid anti-inflammatories so things like tylenol and advil and other trade names and naproxen

00:25:21.440 | sodium things of that sort almost all of those drop body temperature to some extent and that's why

00:25:29.520 | it's often recommended that people take them when they have a fever now a number of athletes especially

00:25:34.720 | endurance athletes will rely on these non-steroid anti-inflammatory drugs specifically to keep body

00:25:40.800 | temperature lower during long bouts of exertion this is a little bit of a pharmacologic version of

00:25:48.080 | dumping heat instead of using palmer cooling or you know face face ice pack cooling they're relying on

00:25:56.240 | pharmacology to drop their core body temperature that has certain obvious advantages lower temperature allows

00:26:02.800 | you to go further harder with more intensity however they do have effects on the liver and they can

00:26:09.680 | also have effects on the kidneys and during long bouts of exercise or even short bouts of exercise

00:26:14.320 | water balance and salt balance are also going to be vital to maintain in order to perform well

00:26:20.800 | generate the best muscle contraction stay mentally alert and also to stay alive you probably want to think

00:26:26.880 | carefully about whether or not you want to use non-steroid anti-inflammatories before any training

00:26:32.240 | session just for the performance augmentation effect unless you're working carefully with a coach

00:26:38.400 | i personally am more a fan of cooling of the palms cooling of the of the bottoms of my feet right by placing

00:26:45.760 | them into a bucket or uh into a cool bath after after training or cooling the face after training or

00:26:52.400 | sometimes even during training it just seems like there's more of a margin to play with the variables

00:26:56.960 | to heat up the water or cool it down a little bit um to include one palm or the other palm

00:27:03.280 | there's just all sorts of uh good parameter space as we call it in science that you can play with and work

00:27:09.120 | with to find what works for you as whereas when you pop a pill sure you can adjust the dose and you can

00:27:14.880 | adjust it next time but once it's in you it's in you and there's going to be some period of time before you can

00:27:20.400 | modulate it so it doesn't give you a lot of opportunity to play scientist which is what i like

00:27:24.880 | to do because what i'm always trying to do is trying to dial in the best protocols possible

00:27:29.840 | based on the mechanisms and data and if you can do that moment to moment that places you in a position

00:27:34.000 | of power once again we've covered a lot of material by now after seeing this episode or listening to this

00:27:40.400 | episode you should understand a lot about how your body heats and cools itself and the value of that for

00:27:46.880 | physical performance i hope you'll also appreciate that you have tools at your disposal

00:27:52.000 | to vastly improve your physical performance i've given you specific protocols and some direction

00:27:58.080 | but i've also left it slightly vague because as i mentioned earlier i don't know all the environmental

00:28:03.680 | conditions i don't know how hot your yoga studio is or how cool your gym happens to be or your body

00:28:09.120 | temperature or time of day remember your temperature will vary according to time of day going forward we're going to

00:28:14.880 | talk more about temperature and other ways to improve physical performance and skill learning we're going

00:28:20.720 | to talk about specific ways to accelerate fat loss to improve muscle growth to improve suppleness and

00:28:28.480 | flexibility these approaches and mechanisms are anchored deeply in neuroscience and physiology and the

00:28:36.400 | relationship between our peripheral organs which include our skin and our brain and all the organs in between

00:28:43.280 | and last but not least i want to thank you for your time and attention i realize this is a lot of information

00:28:48.960 | i hope you'll find some of it to be actionable and useful for you and for people that you know

00:28:53.120 | and as always thank you for your interest in science

Supercharge Exercise Performance & Recovery with Cooling | Huberman Lab Essentials

Chapters