Using Temperature for Performance, Brain & Body Health | Dr. Craig Heller

Introduction

In this section, Andrew Huberman introduces the podcast and his guest, Dr. Craig Heller. They discuss the topics they will cover in the podcast.

Introducing Dr. Craig Heller

• Dr. Craig Heller is a professor of biology and neurosciences at Stanford.

• The podcast will cover thermoregulation and how it can be leveraged to increase performance in athletics and mental performance.

• Learning to control your core body temperature is one of the most powerful things you can do to optimize mental and physical performance.

• The conversation also dispels common myths about heating and cooling the body.

About The Podcast

• This podcast is separate from Andrew Huberman's teaching and research roles at Stanford.

• It aims to bring zero cost information about science and science-related tools to the general public.

Sponsors

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Thermoregulation: What Is It?

In this section, Dr. Craig Heller explains what thermoregulation is, how it works, why it's important for human physiology, and how it can be leveraged to increase performance.

What Is Thermoregulation?

• Thermoregulation is the process by which the body maintains its core temperature within a narrow range.

• The hypothalamus in the brain acts as a thermostat that regulates body temperature.

• The body has two main ways of regulating temperature: sweating and shivering.

Why Is Thermoregulation Important?

• Maintaining a stable core temperature is essential for keeping neurons healthy and organs functioning well.

• The body's ability to regulate temperature affects athletic performance, cognitive function, and overall health.

Leveraging Thermoregulation

• By learning to control your core body temperature, you can optimize mental and physical performance regardless of the environment you're in.

• Dr. Heller explains how athletes can use thermoregulation techniques to improve their performance during competitions.

How To Cool Down Quickly

In this section, Dr. Craig Heller dispels common myths about cooling down quickly and explains what actually works.

Myth: Cold Packs On Head Or Neck

• Putting a cold pack on your head or neck is not the optimal way to cool down quickly.

• It can actually be counterproductive and lead to hyperthermia.

Fact: Cooling Hands And Feet

• Cooling hands and feet is more effective at lowering core body temperature than putting a cold pack on your head or neck.

• This is because hands and feet have high surface area-to-volume ratios, making them efficient heat exchangers.

How To Warm Up Quickly

In this section, Dr. Craig Heller explains how to warm up quickly using thermoregulation techniques.

Warming Up With Exercise

• Exercise increases metabolic rate, generating heat that warms up the body from within.

Warming Up With Hot Water

• Taking a hot shower or bath can warm up the body quickly by increasing blood flow to the skin.

• This is because blood vessels in the skin dilate in response to heat, allowing more blood to flow through them and dissipate heat.

Warming Up With Clothing

• Wearing warm clothing can help insulate the body and prevent heat loss.

• Layering clothing is an effective way to trap air between layers, creating an insulating barrier that keeps you warm.

Conclusion

In this section, Andrew Huberman summarizes the key takeaways from the podcast and thanks Dr. Craig Heller for his insights.

Key Takeaways

• Thermoregulation is essential for maintaining a stable core temperature and optimizing mental and physical performance.

• Cooling hands and feet is more effective at lowering core body temperature than putting a cold pack on your head or neck.

• Exercise, hot water, and warm clothing are effective ways to warm up quickly using thermoregulation techniques.

Thank You To Dr. Craig Heller

• Andrew Huberman thanks Dr. Craig

English InsideTracker and Athletic Greens

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InsideTracker

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English The Science Behind Cold Exposure

In this section, the speaker discusses cold exposure and its effects on metabolism.

Basic Responses at the Level of Metabolism

• When submerging oneself into an ice bath or taking a cold shower for the first time, one gets a tremendous shock which translates into a shot of adrenaline.

• Taking cold baths or showers stimulates vasoconstriction which makes it more difficult for the body to get rid of heat because it shuts off avenues of heat loss.

• If in a true cold bath, the overall surface area of the body is so great that it doesn't matter if one is vasoconstricted; heat loss still occurs.

The Primary Sites of Heat Loss

This section discusses the primary sites of heat loss in the human body and how they work.

Special Blood Vessels for Heat Loss

• The palms of your hands, the soles of your feet, and the upper part of your face are avenues for heat loss.

• These areas have special blood vessels that can shunt blood from arteries to veins, bypassing capillaries.

• Shaking someone's hand can indicate their thermal status based on whether their hand is hot or cold.

Cold Shower vs Immersion in Cold Water

This section discusses the differences between taking a cold shower and immersing oneself in cold water.

Boundary Layer

• In a cold bath, a boundary layer develops which insulates the skin from the still water.

• Moving around disturbs this layer and makes you feel colder again.

• In contrast, a cold shower does not allow for a boundary layer to develop.

Physical Differences

• There are physical differences between being in a cold bath versus taking a cold shower.

• If you're still in a cold bath, you won't lose as much heat as if you were flailing around.

Benefits of Cold Bath or Shower Before Aerobic Activity

This section discusses how taking a cold bath or shower before aerobic activity can benefit performance.

Increasing Capacity to Absorb Excess Heat

• Doing aerobic activity gradually raises body temperature which impairs performance.

• Taking a cold bath or shower before aerobic activity increases the capacity of your body mass to absorb excess heat.

Performance Benefit

• Taking a cool shower before going for long runs could increase speed or help some people go farther.

Pre-Workout Cold Immersion

In this section, the speaker discusses the benefits of cold immersion before a workout and how long it should be done for.

Benefits of Cold Immersion

• Doing cold immersion before a workout can help with heat absorption during exercise.

• It only takes a few minutes to extract heat from the body after cold immersion.

• For anaerobic athletes, such as strength athletes, local muscles will heat up but not the core temperature.

Anaerobic Exercise and Heat Production

In this section, the speaker explains how anaerobic exercise can cause muscle overheating and failure.

Muscle Overheating

• During anaerobic exercise, certain muscles are used which causes them to heat up.

• The blood flow to that muscle cannot go up 50 or 60-fold. So you literally have the capacity to cook your muscles.

• An enzyme critical for getting fuel is temperature-sensitive. When muscle temperature gets above 39 or 39.5 degrees Celsius, it shuts off and essentially shuts off fuel supply to mitochondria causing muscle failure.

Mechanism of Energy Production in Muscles

In this section, the speaker explains how energy production in muscles works and why overheating occurs during anaerobic exercise.

Energy Production in Muscles

• Most of the energy in our food is lost as heat due to inefficiency.

• Mammals use that heat to keep their body temperature considerably above the environment. However, raising body temperature too high can cause hyperthermia.

• An enzyme critical for getting fuel is temperature-sensitive. When muscle temperature gets above 39 or 39.5 degrees Celsius, it shuts off and essentially shuts off fuel supply to mitochondria causing muscle failure.

Understanding Muscle Failure

In this section, the speaker discusses how heat triggers a mechanism that shuts off muscles and causes them to fail. They also explore why cooling down muscles is not as effective as one might think.

Heat as a Limiting Factor

• Muscles associated with an exercise fail due to heat triggering a mechanism that shuts off the muscle.

• Temperature is one of the limiting factors for upper body fatigue curve influenced by lower body exercise.

• Heat is one of the mechanisms involved in preventing more work and can happen quickly.

Cooling Down Muscles

• Body surface acts as an insulator, making it difficult to cool down muscles by throwing a cold towel on them.

• Drinking ice water can help absorb some heat but has limited capacity.

• Applying an ice pack or squeezing a cold sponge over the head may not be very effective in cooling down overheated muscles.

The Thermoregulatory System

• The brain contains a thermostat called preoptic interior hypothalamus that regulates physiological functions, including temperature control.

Cooling the Body Surface

In this section, the speakers discuss how cooling the body surface can affect core temperature and heat loss portals.

Cooling the Body Surface

• Putting a wet washcloth over your thermostat can cause it to do the wrong thing.

• Cooling the torso with an ice vest can cause vasoconstriction of heat loss portals, impairing heat loss rate.

• Putting a cold towel around the neck puts a cold stimulus into the brain, making you feel cooler than you are.

Effects of Hyperthermia on Cognition

In this section, the speakers discuss how hyperthermia affects cognitive capacity and post-exercise effects on heating and cooling of the brain that might impact cognition.

Hyperthermia and Cognitive Capacity

• Rise in temperature decreases cognitive capacity.

• At about 39 degrees Celsius, simple activities like adding and subtracting become difficult to perform.

Heat Loss Portals

In this section, the speakers discuss what heat loss portals are and how they work.

Understanding Heat Loss Portals

• The natural portals for heat loss are our air conditioners - thermostats in our brains that receive information from our overall body surface.

• Cool, calm, and collected is always the goal in all pursuits.

• The preoptic area of hypothalamus acts as a thermostat collecting information from all over our body.

Body Temperature Regulation

In this section, the speakers discuss how the hypothalamus regulates body temperature and what happens when the body temperature gets too high.

Hypothalamus and Body Temperature

• The thermal afferent information goes to both the hypothalamus and somatosensory cortex.

• The information going to the hypothalamus is an integrated representation of body temperature.

• Feeling good from cold exposure can be deceiving because other parts of the body may still be warm internally.

Hyperthermia Symptoms

• Symptoms of hyperthermia include feeling exhausted, miserable, and having a high heart rate.

• Individuals transitioning into heat stroke vasoconstrict and stop sweating.

• People can overcome their bad feeling with motivation to continue going, leading to high-profile athletic deaths due to heat stroke during practice.

Glabrous Skin

• Mammals evolved special blood vessels in limited surface areas that don't have fur for heat loss regulation.

• These blood vessels are shunts between arteries and veins.

Physiology of Blood Flow

In this section, the speaker discusses the physiology of blood flow and how it works in the body.

Blood Flow in Capillaries

• The speaker explains that there are shunts beneath glabrous skin that go directly from arteries to veins, skipping capillaries.

• These vessels are located below the epidermis and can be seen when warm by looking at the palms of your hands which will appear red.

Importance of Heat Loss

• The speaker explains that gripping handlebars too tightly while cycling on a hot day can limit performance due to increased heat retention.

• Gloves impede heat loss from hands, so thinner protectors are better for maximizing heat loss.

• Running with loose hands is more beneficial for performance than gripping a phone or other object.

Compartmentalization of Heat Loss

• The upper half of our face and bottoms of our feet have less fur because they are areas where our primate ancestors did not have fur.

Cooling the Brain

In this section, Dr. Rhonda Patrick discusses how cooling the glabrous skin surfaces can cool the brain and potentially offset physical damage.

Blood Vessels in the Skull

• Blood vessels called emergent go through the skull and are primarily thought to be ways that blood is leaving the brain.

• When overheated, the direction of flow in those blood vessels reverses, allowing cool blood from facial regions to cool down the brain.

Cooling Mechanisms for Brain Injury

• Cooling can decrease swelling and inflammation in many parts of the body, including the brain.

• It's hard to investigate if cooling offsets physical damage or negative effects of concussion.

Observation on Anaerobic Exercise

• Cooling has a benefit to increase work volume and capacity to do more reps.

• Greg Clark, a tight end at Stanford University, was able to do 40 dips in a first set and five sets after proper cooling using glabrous skin surfaces.

Improving Performance with Cooling

In this section, the speaker discusses how cooling can improve an athlete's performance.

Cooling and Improved Performance

• The subject's second set was much better than his control day after cooling.

• The subject cooled his palms for three minutes between sets.

• After four weeks of cooling, the subject tripled his total work volume.

Delayed Onset Muscle Soreness (DOMS)

In this section, the speaker discusses delayed onset muscle soreness (DOMS) and its relationship to workout capacity volume.

DOMS and Workout Capacity Volume

• DOMS is due to micro tears in muscles that occur during anaerobic training.

• Despite exceeding their previous goals, athletes rarely experience significant muscle soreness.

• A study showed that those who were cooled did not have significant muscle soreness.

Portable Equipment for Endurance Workouts

In this section, the speaker discusses portable equipment for endurance workouts.

Portable Equipment for Endurance Workouts

• Current equipment is not portable enough for running or cycling.

• Golfers have used cooling devices on their golf carts to improve performance.

Special Ops Soldiers and Golfers

In this section, the speaker talks about how special ops soldiers tested their technology for a week. They also discuss how golfers have been using the technology to hit their balls further.

Special Ops Soldiers

• The speaker mentions that they used special ops soldiers as subjects to test their technology.

• The soldiers were hard-driving guys who didn't like to quit.

• The soldiers took the technology with them when they left and wanted to keep it.

Golfers

• The speaker mentions that the technology has added 20 yards to every club in his bag.

• The technology allows people to hit their golf ball further.

• Individuals with multiple sclerosis are temperature-sensitive, but some have been able to play golf again by using the device on their cart.

Endurance Testing

In this section, the speaker talks about endurance testing and how they were able to double endurance in one trial with proper cooling.

Endurance Testing

• The speaker mentions that most of their endurance testing has been done indoors on treadmills in hot rooms.

• They were able to double endurance for a group of 18 subjects walking uphill on a treadmill in heat up to 40 degrees Celsius with proper cooling.

• They have developed wearable systems that could go under personal protective gear (PPE), which was requested by Ebola workers in Sierra Leone.

Practical Applications of Laboratory Work

In this section, the speaker talks about the practical applications of laboratory work and why we haven't heard more about it.

Practical Applications

• The speaker mentions that the military special operators are excited about the technology, but they don't have it yet.

• The best laboratory work in its practical applications oftentimes requires many studies.

CoolMitt Technology

In this section, the speaker talks about where to get the CoolMitt technology and its availability.

Availability of CoolMitt Technology

• The company that produces the technology is Arteria, A-R-T-E-R-I-A.

• The website for purchasing the product is www.coolmitt.com or coolmitt.com.

• Currently, the technology is only available to professional sports teams and military personnel.

• However, interested individuals can sign up on the website to be notified when it becomes available for purchase.

How CoolMitt Works

In this section, the speaker explains how CoolMitt works and why it's different from other cooling methods.

Description of CoolMitt Technology

• The user puts their hand into a mitt or glove that cools their hand and through a specialized portal cools their core body temperature and all muscles in their body.

• It's not ice-cold but just cool enough to provide benefits without causing reflex vasoconstriction.

• Putting your hand in cold water causes reflex vasoconstriction which reduces heat loss from portals you're trying to maximize heat loss from.

Duration of Use

• Standardized use time is three minutes as it gets the best part of an exponentially declining curve.

• Longer durations are possible but with diminishing returns after three minutes.

Use by Professional Sports Teams and Military Personnel

In this section, the speaker discusses how professional sports teams and military personnel use CoolMitt technology.

Use by Professional Sports Teams

• NFL teams, college teams, Olympics participants, Major League Baseball players, NBA players, National Tennis Association players are using it.

• They test out new versions of the technology and report back on how it's working, how it could be changed or improved.

Use by Military Personnel

• The Navy SEALs are using CoolMitt technology.

Incognito Use by Athletes

• It's possible that athletes use the technology incognito but there is no information available on this.

• The football team at Stanford University does not use it as they mostly play in cold weather.

Cooling the Body for Performance Enhancement

In this section, the speaker discusses how cooling can enhance performance and shares a crude protocol for cooling in the gym.

Crude Protocol for Cooling in the Gym

• Hold a cold pack of peas or any other cooling medium in one hand and switch it to the other hand.

• Check if your palms feel cool to someone else's touch. If they do, it means you've vasoconstricted and sealed in more heat, which is bad.

• Use a water-profused pad with cool water circulating through it to put your feet on.

• Increase heat exchange by having convection on both sides when transferring heat between two objects.

Convection, Radiation, and Conduction

• Radiation occurs when an object emits energy as electromagnetic waves.

• Convection occurs when there is a convective stream of the cooling medium that increases heat exchange between two objects.

• Conduction occurs when there is direct contact between two objects that transfers heat from one object to another.

Standard Treatment for Hyperthermia

• The speaker mentions a study they published investigating the standard treatment for hyperthermia in the field but does not provide further details.

Cooling the Body

In this section, the speaker discusses how to cool the body effectively.

Cooling Strategies

• Studies have shown that placing cold packs on the face, hands, and bottoms of feet cools the body twice as fast as putting them in the axilla, groin, or back of neck.

• The rationale for placing cold packs on the face, hands, and bottoms of feet is to increase the heat loss capacity of the radiating surface. This is much more effective than hitting arteries close to major arteries.

• The standard operating procedure is to cool hot stuff heading towards the core by hitting arteries and veins.

Heating a Hypothermic Person

In this section, the speaker shares a story about a hypothermic person and discusses how to heat up a hypothermic person effectively.

Story About Hypothermia

• A friend who was an experienced cold water swimmer went hypothermic during a swim. They heated his torso but left his extremities exposed.

• The lifeguard took his vitals and tried to heat him up by heating up his torso. They eventually got him warm liquids and he recovered.

How to Heat Up a Hypothermic Person Effectively

• To heat up a hypothermic person effectively, it's important to cover their extremities and head with blankets or clothing while heating their torso.

Warming Up After Anesthesia

In this section, the speaker discusses the challenges of warming up patients after anesthesia and a solution they developed to address this problem.

The Challenge of Warming Up Patients

• Patients often become hypothermic after anesthesia due to vasoconstriction.

• It can take an hour or two for patients to stop shivering and return to normal temperature.

• Hospitals typically use warm pads or circulating water perfused pads to warm up patients.

A Solution: Special Blood Vessels in the Hand

• The speaker and his colleague developed a prototype device that used negative pressure suction on an appendage, like an arm, wrapped in a heating pad to pull more blood into that limb and heat it up faster.

• They discovered that it was only necessary to heat up the hand because of special blood vessels called arteriovenous anastomosis (AVAs).

• AVAs are also present in bears and other hairy animals.

Application Beyond Hospitals

• The speaker suggests that people outside of hospitals could benefit from understanding how to warm up when hypothermic.

• For example, holding a warm mug of cocoa may not be as effective as using palmar cooling by lowering just the bottoms of one's paws into cool water.

Warming Up and Measuring Core Body Temperature

In this section, the speaker discusses the importance of warming up before exercise and how to measure core body temperature accurately.

Importance of Warming Up

• Warming up is important to lubricate joints and increase flexibility.

• The ability of mitochondria to produce energy can be impaired at lower temperatures.

• Shedding layers as you go is a rational practice for warming up.

Measuring Core Body Temperature

• The best way to measure core body temperature is through an esophageal thermocouple.

• Tympanic (ear) measurement is also effective but not foolproof.

• Laser readings on the forehead are crude, but there's less insulation between the brain and skin in that area.

• Infrared technology can take surface temperature measurements, but it's not as accurate as other methods.

Improving Sports Gear for Performance

In this section, the speaker discusses how sports gear can be improved to enhance performance.

Helmets and Gloves

• Knit caps are significant in cold weather because they decrease constant heat loss from the head.

• Helmets should be ventilated with enough space and holes for air circulation. Insulating your scalp will decrease heat loss considerably.

The Benefits of Cooling Between Sets

In this section, Dr. Andrew Huberman discusses the benefits of cooling down between sets during a workout.

Performance-Enhancing Effect

• Cooling down between sets can lead to a performance-enhancing effect.

• This effect is due to the body adapting and being able to do more work per unit time or go harder in some way.

• This adaptation leads to a true conditioning effect, allowing you to keep your gains and respond to increased work volume by increasing the number of contractual elements in your muscles.

Experiment with Female Students

• An experiment was conducted on female students doing 10 sets of pushups with or without cooling.

• Some students were able to reach over 800 pushups without taking longer than 45 minutes total for the workout.

Anabolic Steroids vs Palmar Cooling for Gym Performance

In this section, Dr. Andrew Huberman compares anabolic steroids and palmar cooling for gym performance.

Research on Steroids

• There is a lot of research on strength conditioning magazines about steroids, but not all are scientific.

• Reputable papers show that there are eight or nine studies on bench press performance increase with or without steroids.

Rate of Improvement

In this section, the speaker discusses the rate of improvement in independent studies.

Independent Studies

• The rate of improvement in all independent studies was approximately 1% per week.

• The speaker mentions a study where there was a 300% increase in performance within a month.

Performance Enhancement

In this section, the speakers discuss performance enhancement and how people pay attention to nutrition and sleep.

Temperature as a Parameter

• Temperature will be one of the more powerful parameters that people are going to be focusing on due to its magnitude of effects.

Military Special Operators

• Military special operators are particularly interesting because their whole world is centered around elite and high performance with very high risk, high consequence under variable conditions.

Female Athletes and Steroids

In this section, the speakers discuss female athletes and steroids.

Comparative Study on Females

• A comparative study on females showed similar results to males when using steroids.

Stanford Athletes or Students?

• The study was conducted on Stanford students who were not athletes. However, they have done work on some athletes but generally do not conduct research on varsity teams as they have their own protocols and training programs.

Shivering and Metabolism

In this section, the speakers discuss shivering and metabolism.

Shivering for Increasing Metabolism

• Shivering is useful for increasing metabolism but can only take metabolism up maybe three or four times resting.

• Exercise can take metabolism up 10 times.

Deliberate Shivering

• Deliberate shivering without cold is essentially what happens when you get a fever. Your set point goes up in your hypothalamus and you actually, even though you're a normal body temperature, your thermostat is telling you that you're too cold, increase your metabolism.

Do Bears Hibernate?

In this section, the speaker discusses bears and hibernation.

True Hibernation

• Whether or not bears truly hibernate depends on how one defines true hibernation. However, they have done a lot of work on bears.

Hibernation and Brown Fat

In this section, the speakers discuss hibernation in bears, ground squirrels, and marmots. They also talk about brown fat and its role in producing heat.

Hibernation in Bears

• Researchers have implanted 18 wild bears with EEG, EKG, temperature sensors, and sometimes oxygen consumption measurements.

• The bears are kept in an outdoor enclosure at the University of Alaska where they hibernate for six months.

• During hibernation, bears maintain a core temperature of 33-34 degrees Celsius by shivering if necessary.

Hibernation in Ground Squirrels and Marmots

• Ground squirrels and marmots can drop their body temperature to within one or two degrees Celsius of the environment during bouts of hibernation.

• They stay in hibernation for seven or eight days before coming back up to normal body temperature for a day before going back down again.

Brown Fat

• Brown fat is a tissue that produces heat.

• It has lots of stored energy because it's fat but also has many mitochondria and blood supply.

• In humans, brown fat is distributed along with other fat tissue rather than being localized into discrete fat pads like it is in ground squirrels and marmots.

Brown Fat and Brain Freeze

In this section, the speakers discuss brown fat activation and brain freeze. They explore the effects of cold on the body and how it can activate brown fat. They also discuss the phenomenon of brain freeze and its causes.

Brown Fat Activation

• Putting ice where your spinal cord is close to the surface can hit vertebral arteries, essentially putting a cold source into the brain.

• Lowering core temperature turns on shivering and brown fat.

• Any lowering of core temperature that lets the thermostat say you're too cold will turn on sympathetic nervous system response.

• Newborns have more brown fat than adults because they cannot shiver.

Brain Freeze

• Brain freeze occurs due to a vasomotor change that increases blood pressure going to the brain, causing an expansion of arteries and activating pain receptors in blood vessel walls.

• Rubbing tongue on roof of mouth may insulate it from direct cooling effect from Popsicle causing brain freeze.

• Preliminary data suggests that using a device to heat may alleviate migraines, but further research is needed.

Anecdotal Reports and NEAT

In this section, the speakers discuss anecdotal reports of ice headaches and increased blood pressure. They also talk about non-exercise induced thermogenesis (NEAT) and how muscle activity increases energy consumption.

Anecdotal Reports

• Ice headaches and increased blood pressure have been reported anecdotally.

• Eating very hot chili peppers can cause thunderclap headache, which is severe enough to cause stroke or brain damage.

• Very hot peppers have been shown to cause brain damage.

NEAT

• Non-exercise induced thermogenesis (NEAT) refers to non-activity associated thermogenesis.

• Some people who overeat burn off that energy by shaking their knee or moving around a lot.

• Muscle activity increases energy consumption and heat production.

• Hyperthyroidism or fidgeting increases metabolic rate and body temperature.

• Any kind of muscle activity increases energy consumption, even if it's only 20% effective.

Energy Drinks and Thermogenic Compounds

In this section, the speakers discuss the use of energy drinks containing thermogenic compounds such as caffeine, arginine, beet juice, and L-citrulline. They also talk about how caffeine reduces adenosine release in muscles.

Energy Drinks

• Many energy drinks contain thermogenic compounds such as caffeine, arginine, beet juice, and L-citrulline.

• These compounds are used to increase body temperature or blood flow to muscles during resistance exercise.

Caffeine

• Caffeine is an adenosine antagonist that reduces oxygen utilization in muscles by reducing adenosine release.

• Caffeine makes you more jittery and increases NEAT.

• It's unclear whether caffeine hinders muscular performance.

Adenosine, Blood Flow and Stimulants

In this section, the speakers discuss the effects of adenosine on blood flow and how stimulants can inhibit the adenosine system. They also talk about energy drinks and their ingredients.

Adenosine and Blood Flow

• Stimulants that include caffeine can inhibit the adenosine system which supports oxygenation of muscle.

• Adenosine causes sleep while caffeine keeps you awake. Staying awake increases metabolic rate compared to sleeping.

Energy Drinks

• Energy drinks usually contain a cocktail of vasodilators, caffeine, some sort of stimulant, glucose (sometimes), and nootropics.

• Vasodilators are often included in energy drinks along with compounds that increase acetylcholine or norepinephrine transmission.

Sleep Hygiene

In this section, the speakers discuss cognitive behavioral therapy as a way to improve sleep hygiene. They also mention general rules for better sleep hygiene such as having regular bedtime and wake-up time, avoiding screens before bedtime, relaxing before bed, taking warm baths before bed, and keeping a cooler environment for sleep.

Cognitive Behavioral Therapy

• The sleep medicine community now puts more emphasis on cognitive behavioral therapy than pharmacology.

• Cognitive behavioral therapy increases sleep hygiene by following general rules such as having regular bedtime and wake-up time.

General Rules for Better Sleep Hygiene

• Avoid screens within a couple hours of bedtime because they emit blue light which affects circadian rhythm.

• Relax before bed and avoid working right up until bedtime.

• A warm bath is conducive to good sleep for many people.

• Keeping a cooler environment for sleep makes sense in terms of the circadian effect on body temperature.

Passive Regulation of Body Temperature

In this section, Dr. Craig Heller discusses how we can passively regulate our body temperature by taking advantage of our heat loss surfaces.

Sleeping in a Cool Room

• Sleeping in a cool room allows us to move our glabrous surfaces (such as one leg hanging out of the blanket) in and out, which helps regulate body temperature.

• This is because these surfaces are sensitive to temperature changes and can help us feel cooler or warmer depending on the environment.

Socks While Sleeping

• Wearing socks while sleeping can promote thermal comfort by insulating the toes, which are the most temperature-sensitive spots in the body according to an old study supported by Eddie Bauer.

• However, if it's too warm, wearing socks may not be necessary.

Conclusion and Call-to-Action

In this section, Dr. Andrew Huberman concludes his discussion with Dr. Craig Heller and provides information on how to support research at the Huberman Lab at Stanford.

Call-to-Action

• Interested individuals can register their interest for palmar cooling technology from CoolMitt on their website.

• To support research at the Huberman Lab at Stanford on stress, human performance, sleep and trauma, visit hubermanlab.stanford.edu/giving to make a tax-deductible donation.

Closing Remarks

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Thorne Discount Code

In this section, the speaker provides a discount code for Thorne products.

• Thorne offers a 20% discount on their products.

• To get the discount, visit thorne.com/u/huberman.

• Use the provided link to access the website and apply the discount code.

Thank You for Your Interest in Science

The speaker expresses gratitude towards the audience for their interest in science.

Closing Music

The video ends with energetic rock music.