Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. I’m Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford, but is part of my desire and effort to bring zero cost to consumer information about science and science-related tools to the general public.

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This episode marks the beginning of a new topic for the Huberman Lab Podcast. As many of you know, we explore a particular topic in depth over four or five episodes.

We just closed out the episodes on hormones and now we are going to talk about how to optimize physical performance and skill learning. We’re going to look deep at the science behind this as well as specific practices. In fact, today, you’re going to hear about specific tools that you can use to improve endurance and strength by up to three or four times your current capacity. This is based on studies that were done at Stanford and are currently in use by collegiate and professional teams.

If you’re not a professional athlete or a serious athlete, that’s okay. The topics this month and all the information we are going to cover are going to make you a better recreational exerciser as well. If you’re not an exerciser and you’re thinking about getting into that, or if you live in the Northern hemisphere and you’re just thinking about the beach this summer or fat loss, muscle building, that sort of thing, this month we’re going to cover all of that as well.

There’s so much confusion out there about how to optimize fat loss, muscle building, improvements in flexibility, for instance, or skill learning. I know many of you aren’t so focused on the cosmetic aspects of physical exercise but are interested in actual skill learning, we’re going to talk about that too.

We want to take a moment to reflect on something that came up in the last episode. If you didn’t see that episode, that’s quite all right. In the last episode, we were talking about the hormones, adrenaline, and cortisol, and how to leverage those towards attention and learning. There was a little bit of confusion that I want to clarify.

I mentioned an optimal protocol for learning that involves leveraging adrenaline, also called epinephrine, and it involved four steps. The steps were to be calm and focused while trying to acquire or learn the new skill, cognitive skill or motor skill. Then, to have a spike in adrenaline using cold or breathing or other tools, immediately after the learning episode. After that, to incorporate what I call non sleep deep rest, a 20 minute episode of a shallow nap or some other protocol. Finally, to try and optimize sleep later that night and the subsequent night.

Some of you heard this and it sunk in right away, while others said, “Wait, I thought from a previous episode even before that, you said you’re supposed to do non sleep deep rest immediately after learning?” No, we added another step. The logic still follows that you want to be calm and focused during learning, then you want to spike adrenaline at the end.

Most people get the process of learning and physical performance backward. They try to increase their focus by drinking too much coffee or taking nootropics and other drugs, such as Adderall, which I do not recommend. The data and physiology suggest that the proper order is to spike adrenaline at the end or immediately after a learning episode, followed by non-sleep deep rest, and then sleep itself.

When it comes to physical performance, there are many variables to consider. We can manage physical performance and skill learning from a variety of contexts, including foundational elements like getting a good night’s sleep, being properly hydrated, and being well nourished. Disrupting any of these elements will lead to poorer performance.

Some of you may like to exercise fasted, while others prefer to have food in their stomach or have eaten a couple hours before. There are many tools related to mindset, visualization, machines, drugs, supplements and devices that can impact and even optimize physical performance and skill learning. However, one of the most powerful tools to improve physical performance and skill learning, with low to zero costs, is temperature. Many may think that the “magic pill” to improve physical performance is something else, but temperature is actually more important than sleep, as it dictates how well and when one sleeps and the depth of total recovery. Temperature has two aspects, heat and cold, with the latter being mainly used to buffer heat.

In a previous podcast episode, I talked all about growth hormone and how heat can be a powerful stimulus for increasing growth hormone which is involved in tissue repair, burning fat and improving metabolism. However, I would argue that cold is even more powerful than heat as a tool. We’re not just talking about putting ice packs on sore muscles or slightly sprained limbs, but rather leveraging compartments in the body that heat and cool differently to double, triple or even quadruple work output in terms of strength, repetitions, and endurance. Furthermore, understanding the physiology of cold and heat can help you to implement the tools in the best and most flexible ways for your needs. At the Huberman Lab Podcast, I never just list the things that you should do without explaining why.

The logical framework that this is grounded in is homeostasis, which is the body’s ability to remain in a particular range of temperatures. This is important for the body’s ability to perform, including learning new skills. To distill this down to specific protocols, there are millions, if not billions, of other resources out there that can take you into the cul-de-sac of one protocol. However, here we are more focused on understanding the mechanism so that you can tweak, modify, and adjust the timing and dosage of things to get the most out of these tools and protocols. This applies to both endurance exercise and strength and speed type exercise, such as sprints and weightlifting, as well as flexibility and suppleness of movement. We will cover flexibility in depth in a subsequent episode. Let’s start by talking about temperature and how it impacts the body.

I want to emphasize from the outset that there are many mechanisms that are installed into us by way of our evolutionary design and our genome. This means that we were born with this stuff ready to keep our body temperature in a particular narrow range. Heating up too much is bad for physical performance and all tissue health. If the brain heats up too much, neurons start dying and these neurons do not come back. Neurogenesis, the ability for the brain to regenerate itself or generate new neurons, is very limited after puberty. Hyperthermia should be avoided as it causes neurons to die in the central nervous system. We also have enzymes in all of our cells which usually end in the letters A-S-E. For example, lipase is an enzyme that exists to digest fats.

Proteases are enzymes that digest proteins. Anytime you see A-S-E, it is likely an enzyme. Enzymes are proteins that have a particular structure, which is modified when heat increases. This is not good as the enzyme will not function properly, like a car with four wheels, if it gets too hot. The body and nature have mechanisms to make sure that we don’t become too warm, as when we do, cells stop functioning, energy is not generated, digestion stops, thinking stops, and cells start dying off. Keeping temperature in a particular range is important and although we have more flexibility in terms of getting cold, we don’t want to become hypothermic either.

Hypothermia and hyperthermia are conditions in which the body’s temperature is outside of the normal range. Hypothermia occurs when the body is too cold and hyperthermia occurs when the body is too warm. The body and brain must stay in a particular range in order to remain healthy. However, our body temperature can shift when we do certain things. For example, standing next to a campfire or being outside on a hot day can cause the body to dump heat, while getting into a cold shower or lake can cause the body to insulate heat. In order to regulate body temperature, the body secretes adrenaline when in cold water, and heat shock proteins when in a hot environment such as a sauna or desert.

The simplest way to think about this process is that when we get cold, our blood vessels tend to constrict, pushing energy toward the core of our body to preserve our core organs. Our hands, feet, toes, and legs become colder, while our core maintains blood flow. Conversely, when we heat up, our blood vessels vasodilate and expand, allowing more blood to move throughout the body. We may perspire, with water pulled out of the blood and moved up through sweat glands to be dumped at the skin surface. Animals vary in their capacity to sweat; dogs pant, while camels spit. Humans can sweat, but on a humid day, the air does not allow transfer of sweat into the atmosphere as readily, resulting in sweat stains.

On a hot day, we evaporate off sweat to cool down. We also vasodilate to dump heat and vasoconstrict to maintain heat. When it’s cold, we get goosebumps, which are a throwback to the time when we had fur over most of our body. The process of pilo erection occurs when adrenaline is released into the body, activating sympathetic fibers that reach up into the skin. On a hot day, the hairs lie down to let more heat dissipate out through the skin, while on a cold day, the hairs stand up to insulate the body.

The hair of certain animals, such as Malamutes and Huskies, can act as an insulated blanket of warm air. On hot days, the animal will pant and its hair will lay down. On cold days, their hair will stand up on end, trapping heat between the hairs and creating a well-insulated layer. To understand how to leverage temperature for physical performance, it is important to understand vasoconstriction to conserve heat, vasodilation to dump heat, sweating to dump heat, and conservation of fluids to preserve heat. If you get too hot, not only will the enzymes stop working, but your ability to contract your muscles will also stop. This is because the range of temperatures within which ATP can function and muscles can contract is very narrow.

At around 39 or 40 degrees Celsius, it drops off and you will not be able to generate more contractions. This temperature can be generated locally really fast, but if you’re too cold it’s hard to generate muscle contractions. I got into cold water swimming a while ago and we would joke that when you come out of the water, you feel like you have claws for hands and can’t even move your face.

Heating up muscles causes them to fail to be able to generate more contractions. Put simply, if you get too hot, you stop exercising, without even realizing it. Your will to exercise further and your ability to push harder is entirely dependent on the heat of your muscle and your whole system. I just described heat dumping and heat maintaining, which can help regulate your body temperature.

If you can keep your body temperature in a proper range, you will be able to do more work and create greater output. This has been demonstrated by data from Craig Heller’s lab in the department of biology at Stanford, which is now being implemented in many NFL teams, as well as firefighters, construction workers, and other professions.

Proper cooling of the body has allowed recreational athletes, college students, and typical adults, as well as professional athletes, to go from doing their usual output to impressive results. For example, a member of the 49ers at the time was able to do 10 sets of dips unassisted, starting with 40 reps on the first set and ending with 10 reps on the last set.

40 dips is a respectable effort, especially for a large guy. These were strict, full-range dips and by the 10th set there was a steep drop-off. However, using proper cooling of particular body compartments, it was possible to triple the performance within less than a week and maintain it even without the cooling approach. This was due to a conditioning effect. There were other fantastic leaps of effort and performance demonstrated, including endurance running.

It is important to note that overheating is terrible and can have deadly consequences. This was evidenced by a number of dietary supplements that included stimulants like epinephrine and Clenbuterol which were then banned from the Olympics and are still in recreational use. These drugs improve fat loss due to their effects on metabolism, but they can also heat up the body. This became apparent when high school football players and professional athletes were dropping dead due to overheating during practice or in competition.

Clenbuterol is a drug that was banned due to its dangerous side effects, such as hyperthermia. Recently, an incident of its use in professional boxing was attributed to contaminated meat. It increases body temperature and fat loss, but carries severe danger. My first project in science was to evaluate the thermogenic effects of MDMA or ecstasy, and we found that drugs that remove your understanding of how warm you are can cause you to not take on the appropriate behaviors to cool yourself. To prevent overheating, the main thing to do is stop.

When we are running in the desert or when we are running very hard and suddenly we stop, oftentimes this is because our muscles are overheating. This is a subconscious thing; we don’t often think, “I’m really much too warm,” but instead we just stop. This is a self-preservation mechanism, and it can kick in too early or too late. If it kicks in too late, it can be deadly.

As an example, during the 1984 Olympics there was the first year of the women’s marathon. One of the front runners, who was in position to win or at least take second place, got totally disoriented and did miserably in the race. It was later discovered that she was hyperthermic and running against the reflex to stop.

In order to perform longer safely, it is key to dump heat. To understand this, you must understand that the body has three main compartments for regulating temperature. Understanding how these compartments work can have a tremendous impact on performance and recovery.

You have three compartments for increasing or dumping heat in your body: your core (organs such as the heart, lungs, pancreas, and liver), your periphery (arms, legs, feet, and hands), and a third component with three locations on your body that are better at passing heat out of the body and bringing cool into the body quickly—your face, the palms of your hands, and the bottoms of your feet. The skin on these areas is called glaborous skin, and what makes it special is the arrangement of vasculature (blood vessels, capillaries, and arteries) that serve these regions is very different than elsewhere in the body.

Now, this has ancient roots. Typically, if you were another mammal, like a bear or some sort of ape, you would have hair all over your body. We all know some pretty hairy people and I know a few excessively hairy people. However, Castilla is excessively hairy, but he’s not a person obviously. All mammals have hair on their bodies, too. Some people have very light hair or very fine hair, but we don’t have hair on these glaborous skin regions. Of course, you can have beard or facial hair growth, but there are still regions like the cheeks and other areas that maintain this special vasculature.

The hands and feet are real glaborous skin and the face is not always quite classified as glaborous, but these three locations – face, palms of hands and not tops and bottoms of feet – are very good at dumping heat and bringing in cool. The reason is there’s a rule in vascular biology that blood moves from arteries to capillaries and then to veins, and then back to the heart. Arteries are the big ones, capillaries are the little fine ones where oxygen and carbon dioxide are exchanged, and veins then bring blood back to the heart and other tissues of course.

AVAs are a special pattern of vasculature found in three regions of the body: the hands, face, and bottoms of the feet. They are described in medical textbooks, such as Grey’s Anatomy (the textbook, not the television show). AVAs are arterio-venous anastomosis (A-R-T-E-R-I-O, V-E-N-O-U-S, A-N-A-S-T-O-M-O-S-E-S). These AVAs allow us to heat or cool ourselves more readily in these regions. In particular, they are found on the palms of the hands, not the tops.

Now, before I said blood flows typically from arteries to capillaries, to veins, and then back to the heart. But AVAs (Arterio-Venous Anastomoses) are direct connections between the small arteries and the small veins. They bypass the capillaries to some extent, and are little short vessel segments with a big, large inner diameter and a very thick, muscular wall. They get input from what are called adrenergic neurons, which release norepinephrine and epinephrine, allowing them to contract or dilate.

There is a rule of physics that states that the radius of a pipe and small changes in the radius of a pipe leads to massive increases in the rate and amount of stuff that can flow through it. What is important to know, even without having to understand the underlying physics, is that these AVAs allow more heat to leave the body more quickly and more cool to enter the body more quickly than other venous arterial capillary beds throughout the body.

In other words, you can heat up best at the face, the palms and the bottoms of the feet, and you can cool down best at the same three compartments of your body than you can anywhere else on your body. And when I say heat up or cool down, I mean actually heat or cool the core end your brain. Okay, so this is vitally important. I realize we’re getting down into the mechanistic weeds here, but you need to know that these three compartments of your body, palms, bottoms of feet and face are your best leverage points for manipulating temperature to vastly improve physical performance, okay?

I also want to point out that the work that I’m going to tell you about is not work from my laboratory. It’s the work of, as I mentioned, my colleague Craig Heller’s laboratory at Stanford and we’re going to have Craig on as a guest to talk more about these discoveries, they are his and his colleagues discoveries and how you can leverage them. They’re building out some amazing technology. I had a conversation with Craig yesterday as a prelude to this episode and to the future conversation with him so you’re getting the very latest on this topic.

So what Craig and his colleagues did really illustrates perfectly what these body surfaces can do and why. They were studying overheating in athletes and in military and in construction workers and trying to prevent it.

Craig and his colleagues conducted experiments that found that cooling the palms—palmer cooling—allowed athletes and recreational athletes to run much further, lift more weight, and do more sets and reps to a staggering degree. This begs the question of why we shut off effort when we get too hot. Enzymes, such as pyruvate kinase, start to get disrupted and ATP and muscles can’t work as well, preventing muscles from contracting. Pyruvate kinase is a rate-limiting step and is very temperature sensitive. This means that if you can keep the temperature lower, you can do more work per unit time, like more pull-ups. Craig and his colleagues tested this theory with both cooled and uncooled pull-ups, though it is unknown how many pull-ups Craig can do.

But what they essentially did is bring someone into their laboratory who could do 10 pull ups on the first set and rest two or three minutes to get another 10. If you’ve ever tried this, you start dropping to eight, seven, six, etc. The person might not necessarily feel like they’re overheating, but the muscle is heating up. With their knowledge that these AVAs, or portals in the palms, are a great way to both heat the body, but also to dump heat from the body, they used a device where they had people hold on to a cold tube. This tube can’t be so cold that it causes vasoconstriction, as then the cold won’t pass from the tube to the hand and to the core. If it’s the right temperature, it’s neither too hot nor too cold, the cool from the cold tube passes into the hand, cooling the core.

In theory, by lowering body temperature, this would allow the person or athlete to do more work. Indeed, the data showed that subjects could do, at least the subjects they worked with, on their first day with no cooling about a hundred pull-ups across the timeframe they had. Then they came back and did the cooling on the very next day. They found that they went to 180 pull-ups, which is incredible, it’s a near doubling. By doing this repeatedly over several sessions, they quickly went in the cooling group from a maximum of somewhere between 180 and 200 to 600 pull-ups in the equivalent amount of time.

Researchers conducted a study on the bench press and found that a control group taking anabolic steroids (testosterone cypionate) improved at a rate of 1% per week. Additionally, the cooling group left all other groups in the dust due to cold passing through the palms because of the unique vasculature there. This allowed the subjects to do far more work per unit time and still recover, even after doing 600 pull-ups or 500 pull-ups. This was both an excellent performance and an excellent training stimulus that professional teams, the military, and others capitalized on quickly. They also found that people could bench press two 25 pound plates on the 45 pound standard Olympic bar for repetitions of six to 10.

Athletes have been able to increase the amount of work they can do by taking breaks between sets and cooling their muscles. This has been demonstrated to be true for endurance as well. There is a physiological relationship between body heat and willpower which explains why we stop when we feel we are putting in too much effort. Heat can shut us down, and if we are cool, we can push ourselves further. People can push themselves to the point of blacking out or even death, but it is not recommended.

People will go until it’s painful and then take a big breath. There are always those individuals who can override that reflex and go until they pass out, however this is very dangerous and should not be attempted. Craig and his colleagues have done laboratory tests in which people run on a treadmill in different temperatures. The heart rate increases from a baseline of 40-50 up to 80-100 and then they plateau. This is a steady state cadence and the person will continue until they reach their pain threshold.

People will eventually stop running at a certain temperature and heart rate due to something called cardiac drift. This happens when the heat component and the heart rate output from the effort hit a certain threshold. Even though some people can run for a long time, eventually everyone stops, either because the race is over or because people quit. Increasing the temperature increases the rate of quitting in part because of cardiac drift, which can be experienced when walking uphill on a hot day or sitting in a sauna.

Heat increases heart rate, effort increases heart rate, and at a steady effort, you’ll have a steady heart rate. However, if you increase the heat in the environment that you’re engaging in, your heart rate will now go up due to cardiac drift and you will quit. Heller and colleagues have done experiments where they do palmer cooling under these environments. This is beneficial as it enables people to go further and faster for much longer, and it also protects the brain and body against hyperthermia, overheating, coma, nerve injury, nerve death, and actual death. To do this, they are having people cool their hands and the palms, and cooling the face could also work. We will be discussing how to incorporate this in further detail.

I want to impress upon you the fact that you have three surfaces of your body – the palms and the bottoms of the feet and the face – that are very good at passing cold into the body, such that it cools the core body temperature. This is good for health and safety, as well as for increasing work output and willpower. Heller and colleagues have also explored how these can be used to heat up the core. Most of the heat escapes through the face, the palms of the hands and the bottoms of the feet. This is important to remember when going outside in cold weather, as we typically hear that most of the heat escapes through our heads and put on a hat.

For post-surgery patients or people that are hypothermic, indeed you want to heat the core. Recently, I was on a swim with a friend who became hypothermic. He was slurring his words and staggering around when we got him back on the beach. We brought him to the lifeguard station and he turned out to be fine. This is why cold water swims should be done in groups and people should know what they are doing. We were walking down the beach sandwiching him between our chests because we were warmer than the environment around us. We were pushing our chest against him to try and warm his core, which in retrospect was the wrong thing to do. In talking with Craig and other colleagues that work on thermogenesis, I now understand why this is the case.

We should have warmed the palms of the patient’s hands, the bottoms of his feet, and his face to insulate heat loss. He was very cold, so presumably there was vasoconstriction of the veins at these locations. This would not have been the only strategy to use, but it is one of the best ways to heat up post-surgery patients. To do this, warm socks should be put on the feet, gloves on the hands and, if it can be done safely, the face should be warmed. However, care must be taken not to obstruct respiration. Heat can be passed into the body or removed from the body most effectively through these three surfaces.

Craig and colleagues have spun out a company from Stanford that has made engineered devices to keep the veins open and the size of the veins correct to pass cool into the body quickly for sports performance. This can be incorporated into recreational and elite sports performance.

The answer to the question of how cold should the water be is no – it should not be ice cold or very cold. To experience some of the cooling effect without a device, one thing you could do is put your hands into or on the surface of a sink that is stopped up with cool water. This water should be slightly cooler than body temperature, and the cooling should last for 10 to 30 seconds. After each set, the amount of cooling should be extended to 30 seconds to a minute.

Using a frozen juice can or a very cold can of soda, you can cool your body while running in order to generate more output. Warming your face is the most important thing to do if you tend to run cold. You can do this by wearing a ski mask, although it may look strange. Craig suggested a “poor person’s approach” to this, which is taking a frozen juice can or a very cold can of soda and passing it back and forth between your two hands. This is important because you don’t want it to be too cold and constrict your veins.

Now, there are certainly people that are working on bike handles, and that can actually cool the hands. You can expect with the Olympics coming up, people are aware of these data and are starting to incorporate it into a number of things.

Here’s what you don’t want to do and there are sports teams that I won’t mention by name or brand that have made this mistake and it costs them dearly. You don’t want to cool the core if you want to cool the body, right? If it’s very hot day and you’re going to train, getting into an ice bath first, sure it will cool you down, but it’s not going to be as effective as cooling the palms, the bottoms of the feet and the face.

I have a friend who does some important work in this space with people in various, let’s just say cultures where heat is generated quite a lot and they need to dump heat, ice packs delivered to the face are something that they actually use in order to dump heat quickly.

Now, again, you don’t want to keep the ice pack on your face. These are people that are very high work output, right? Firefighters and similar, at very high work output and then they’ll put this essentially, it’s like a cool face mask on their face. It allow their core body temperature come down and then they remove it, they’re not keeping it on there so long that they’re getting the vasoconstriction, okay?

There are a number of ways that you can use cold to improve your performance and recovery. For example, I recently tried cooling my hands and the bottoms of my feet with a bucket of water that was slightly cooler than body temperature. This resulted in a 60% increase in the number of dips I could do in a single session. You don’t have to be perfectly precise to benefit from cold temperatures. Additionally, you can use cold to improve the speed and depth of recovery.

Recovery is obviously vital during a weight training session or an endurance session, as it is the stimulus for getting better the next time. If you don’t recover, you not only won’t get better, but you will get worse. There is a lot of interest in the use of cold to improve recovery in the short term. An example of this would be fighters in combat sports between rounds or athletes during halftime. Typically, people cool their core, back of the neck, and top of their heads. This could be done with a sponge with cold water, an ice pack, or even a cold ice vest. However, these are inefficient ways to improve recovery. Far better would be to cool the face, palms of the hands, or bottoms of the feet. Submerging the body in an ice bath, taking a cold shower, or jumping in a cold lake would be more effective than getting under a cold shower in the locker room. This is because cooling the palms of the hands, bottoms of the feet, or face are more effective ways to cool off the body quickly.

Cooling the body can help optimize recovery, but it is important to cool only one or two regions of the body and not the whole body. Submerging or covering the body in cold can cause vasoconstriction, which can block the training stimulus. The best way to cool down is to splash cold water on the face, hold a damp cool cloth on the face, or take a cold shower. Cryotherapy, which requires expensive equipment, is not accessible to most people. Therefore, cold baths, ice baths, and cold showers are not recommended for recovery.

When you get into an ice bath or a cold shower, provided the temperature is not too low, you are blocking some of the inflammation that occurs due to the training session. However, this also blocks pathways such as mTOR, which is involved in the adaptation of the muscle to become stronger or bigger. In other words, covering the body in cold or immersing it in cold after training can prevent the muscle growth response. It can also have positive effects, such as inducing thermogenesis and reducing inflammation.

It has not been examined as much for endurance work, but cooling the palms, the bottoms of the feet or the face after a run, bike or swim is better than completely immersing the body in the ice bath or the cold shower. The time and place for the use of the ice bath or the cold shower is when you want to deliberately increase brown fat thermogenesis or work on mental resilience.

I mainly rely on textbooks and special volume books, such as “Thermoregulation in Human Performance, Physiological and Biological Aspects” by Effie Marino, for further information.

No business relationship or deal exists with the publisher or author of the text “Thermoregulation in Human Performance”. This excellent text can be found online and the studies therein show that if the body’s temperature is cooled back to its resting temperature, muscle and tendon recovery is accelerated. It is believed that the best way to maximize return to baseline levels of temperature is to rely on one of three glaborous skin portals: the palms, the bottoms of the feet, or the face. Additionally, one should consider how food, drink, and other substances may impact body temperature.

Many of us are impairing our performance by taking pre-workout drinks, caffeine, and other substances to bring our body temperature up before exercise. This can limit the amount of exercise we can do. I remember taking ephedrine in college to energize myself for workouts, but I now realize this was foolish. It increases core thermogenesis, but data shows that cooling can significantly increase performance if done properly. Taking thermogenic compounds, pre-workout drinks, pills, or high levels of caffeine is the wrong thing to do as it can prevent us from generating good muscle contractions.

It is not advisable to be like the speaker, coming out of the cold ocean with claws for hands. The speaker advises that one should keep their body temperature in a range that still allows them to work hard and perform well. In terms of recovery, alcohol is a vasodilator and can cause people to drop body temperature, however, the speaker does not advise drinking alcohol as it can be a problem for those with alcohol issues, or those who are not of drinking age. The speaker has a friend who is an accomplished athlete and drinks beer after running or cycling, and this is probably a good tool, provided one does not have issues with alcohol. Anything ingested after exercise that increases body temperature will impede recovery, whereas anything that lowers body temperature in safe ranges will accelerate recovery. The speaker advises against taking compounds to increase fat burning and metabolism as this will impede performance, especially if performance is the focus as opposed to body recomposition.

Stimulants such as caffeine and other pre-workout drinks can be beneficial for performance and body recomposition goals. However, the increase in body temperature that results from taking these compounds can block or prevent optimal performance. Therefore, it is important to consider if the increase in energy and performance is worth the potential decrease in performance due to the rise in body temperature. Additionally, stimulants can also affect recovery time, so it is important to consider if other methods to improve recovery, such as hormone augmentation, are being used. Ultimately, it is important to consider the pros and cons of taking stimulants before exercising.

I like yerba mate and I’m a chronic caffeine user. I drink various kinds of coffee, such as mushroom coffee, black coffee, and espresso. I’m not an addict, but I’m used to drinking caffeine, so when I do, my heart rate doesn’t increase as much. For people who don’t drink caffeine often, it will constrict their blood vessels and increase retention of body heat, which is not ideal before exercise. However, for those who are caffeine adapted, it will cause vasodilation and allow them to dump body heat. Therefore, I use it before I train, as it won’t prevent me from sleeping, and afterwards I’m aware that it causes vasoconstriction when the caffeine wears off.

For those who drink two to three cups of coffee or mate a day, which equates to an intake of anywhere from a hundred to 400 milligrams of caffeine, it is best to consume it before exercise and not after. This is due to its thermogenic effects and its ability to constrict blood vessels, making it harder to dump heat. However, for those who are used to consuming caffeine, not drinking it can cause vicious headaches and make it difficult to get motivated. It takes about three weeks to become accustomed to no caffeine. Therefore, if you like caffeine, use it in moderate amounts before exercise, and if you don’t use it often, stay away from it before or after exercise.

Non-steroid anti-inflammatories, such as Tylenol, Advil, and Neproxin sodium, are commonly used over-the-counter compounds and can reduce body temperature. Although fever should not be allowed to go too high, artificially lowering body temperature with these compounds can be tricky. Athletes, especially endurance athletes, may rely on these drugs to keep their core body temperature lower during long bouts of exertion. The advantages of this should be obvious, as lower temperature allows for more intensity and further performance. However, these drugs can have effects on the liver and kidneys and can affect water and salt balance, which are vital for optimal performance and safety. Therefore, when considering using non-steroid anti-inflammatories for performance augmentation, it is important to carefully consider the situation and work with a coach if possible. Additionally, one should be aware of the effects of alcohol, caffeine, and other drugs on temperature and performance.

I personally am more a fan of using caffeine in moderate doses for the reasons I described before, as well as to use the cooling of the palms, cooling of the bottoms of my feet, and cooling the face after or even during training. It just seems like there’s more of a margin to play with the variables, to heat up the water or cool it down a bit to include one palm or the other. There’s all sorts of good parameter space that you can play with and work with to find what works for you, whereas when you pop a pill, you can adjust the dose and you can 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 modulate it.

What I’ve offered today are ways in which you can use temperature to powerfully improve performance. You can vary that from set to set, you could do your pull ups or your sprints and then cool your palms, and then try and go with colder water the next round or warmer water the next round or do both feet and palms and face. This gives you essentially zero cost or no cost, whereas when you pop something, you take a pill, you’re basically in that regimen for the next hour or two or more. You can always take more, but you can’t really take less. You can’t really extract it from your body in real time, so it doesn’t give you a lot of opportunity to play scientists, which is what I like to do. I’m always trying to dial in the best protocols possible based on the mechanisms and data, and if you can do that moment to moment, that places you in a position of power.

Once again, we covered a lot of material. By now, after seeing this episode or listening to this episode, you should understand a lot about how your body heats and cools itself and the value of that for physical performance. I hope you’ll also appreciate that you have tools at your disposal to vastly improve your physical performance. Should you try these, please let us know how it goes. If you decide to do palmer cooling during your runs, weight workouts, yoga sessions, or whatever it is, please place that in the comments.

I’ve given you specific protocols and some direction, but I’ve also left it slightly vague because I don’t know all the environmental conditions, your body temperature, or time of day. Remember your temperature will vary according to the time of day – typically rising early in the day and coming down as you approach the late evening and late night hours for sleep. In the middle of the night, your temperature is very low at its absolute lowest – something we call the temperature minimum. So, you need to take the information that you receive today and, should you try and incorporate it, try and do it intelligently.

Don’t cool yourself off so much that you become cryogenic and please don’t warm yourself up. In fact, we didn’t talk at all about warming yourself up because warming yourself up too much can be quite dangerous. You never, ever, ever want to be hypothermic, that’s what your body and your brain are trying to avoid.

We talked a little bit about supplements but not the standard sorts of supplements I usually list off on these episodes. Rather, we talked about caffeine, non-steroid anti-inflammatories and how those can impact temperature, how alcohol can impact temperature. We also discussed how every time we eat, we increase temperature due to the eating induced thermogenic effect, however, it tends to be really minor and so you wouldn’t worry about eating before training because of its effects on temperature.

Going forward, we’re going to talk more about temperature and other ways to improve physical performance and skill learning. We’re going to talk about specific ways to accelerate fat loss, to improve muscle growth, to improve suppleness and flexibility.

These approaches and mechanisms are anchored deeply in neuroscience and physiology and the relationship between our peripheral organs, which include our skin and our brain, and all the organs in between. It is a pleasure to look to the textbook literature that exists and which has been developed over the last 50 to 100 years. Unlike many areas of neuroscience which are still mysterious, such as consciousness and dreaming, these core mechanisms of temperature and physiology are powerful and involve very concrete studies which are actionable.

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And last but not least, I want to thank you for your time and attention. I realize this is a lot of information and I hope you’ll find some of it to be actionable and useful for you and people that you know. As always, thank you for your interest in science. [upbeat music]