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The Science & Health Benefits of Deliberate Heat Exposure | Huberman Lab Podcast #69

Andrew Huberman・99 minutes read

The Huberman Lab Podcast explores the science of heat, highlighting its impact on metabolism, cognitive function, and health. Deliberate heat exposure, like sauna use, can lead to various health benefits, including increased growth hormone levels and improved mental health.

Insights

Heat, when applied properly, can engage neurochemical systems in the brain and body, enhancing brain function.
New science explores local heating's benefits, such as changing fat cell identity through heat application to increase metabolically active fat.
The preoptic area (POA) in the brain plays a key role in signaling the body to heat up or cool down, influencing physiological responses like sweating and vasodilation.
Sauna exposure upregulates FOXO3 levels, potentially offsetting cardiovascular risks and mortality, with individuals with hyperactive FOXO3 variants more likely to live longer.
Deliberate heat exposure through sauna can significantly increase growth hormone levels, with a specific protocol involving 12-minute exposures to 90-degree Celsius followed by a cool-down break in cold water proven to lower cortisol levels.

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What is the Huberman Lab Podcast about?
The Huberman Lab Podcast discusses science and tools for everyday life, hosted by Andrew Huberman, a professor at Stanford School of Medicine.

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Summary

00:00

Heat Science: Enhancing Health and Metabolism

The Huberman Lab Podcast discusses science and science-based tools for everyday life, hosted by Andrew Huberman, a professor at Stanford School of Medicine.
Today's topic is the science of heat, focusing on how the body heats up from both external and internal sources, impacting various aspects of health like metabolism and cognition.
Heat, when applied properly, can engage neurochemical systems in the brain and body, enhancing brain function.
The podcast delves into the mechanisms of heat and heating, including tools like saunas, discussing frequency, duration, and temperature for specific health goals.
New science explores local heating's benefits, such as changing fat cell identity through heat application to increase metabolically active fat.
A recent study in the journal Cell reveals how heating specific areas can convert white fat to beige fat, boosting metabolism and aiding fat loss.
The podcast is now partnered with Momentous Supplements, offering high-quality supplements with recommended dosages for optimal benefits.
Live events in May 2022 in Seattle and Portland will cover new science-based tools and topics, with Q&A sessions for audience interaction.
The podcast is separate from Stanford roles, aiming to provide free science information, thanking sponsors like LMNT, InsideTracker, and ROKA.
Understanding the body's thermal regulation involves balancing core and surface temperatures, with the brain signaling heating or cooling mechanisms accordingly.

13:06

Heat Impact on Health and Hormones

Understanding the impact of heat on both shell and core is crucial for designing effective protocols for health goals.
Transitioning between hot and cool environments rapidly can increase growth hormone release by 16 fold.
Merely staying in a sauna for an extended period without temperature shifts won't yield growth hormone increases.
Sauna and heat-related tools can optimize health, metabolic health, cortisol control, and mental health positively.
Heat and cold science, dating back over a century, are now gaining renewed interest for health optimization.
Caution is advised when heating the body to avoid hyperthermia, especially for pregnant, nursing, or heat-sensitive individuals.
Neurons in the skin, spinal cord, and brain form a circuit that regulates heating and cooling responses.
The preoptic area (POA) in the brain plays a key role in signaling the body to heat up or cool down.
The POA influences physiological responses like sweating, vasodilation, and behavioral changes to regulate body temperature.
The POA can also activate the amygdala, triggering the sympathetic nervous system's fight or flight response in extreme heat situations.

25:43

Sauna Use for Health and Longevity

The process of heat regulation in the body involves signals from the skin to the spinal cord and between different brain areas, particularly the preoptic area (POA).
The POA triggers autonomic responses like sweating and vasodilation to cool the body, as well as behavioral responses such as spreading limbs and feeling lethargic in hot environments.
Deliberate heat exposure, like sauna use, is highlighted as a method to understand biological changes due to heat and improve health and longevity.
A study from 2018 titled "Sauna Bathing is Associated With Reduced Cardiovascular Mortality and Improves Risk Prediction in Men and Women" demonstrated the benefits of regular sauna use in reducing mortality from cardiovascular events.
Sauna temperature ranges typically vary between 80-100 degrees Celsius (176-212 degrees Fahrenheit), with exposure times ranging from 5 to 20 minutes per session.
People who used the sauna two to three times per week were 27% less likely to die from cardiovascular events compared to those who used it once a week, with even greater benefits for those using it four to seven times per week.
The study involved 1,688 participants with a mean age of 63, showing significant health improvements with increased sauna use.
Various methods, including hot tubs, infrared saunas, and wearing heavy clothing, can be used to achieve heat exposure benefits if a traditional sauna is not available.
The importance lies in reaching the temperature range of 80-100 degrees Celsius for optimal results, regardless of the specific sauna type used.
Personal circumstances, budget, and accessibility determine the choice of heat exposure method, emphasizing the flexibility in achieving the desired health benefits.

38:44

Heat Exposure Benefits: Sauna and Health Benefits

Sauna or deliberate heating activates mechanisms in the brain and body, leading to health benefits like reduced risk of cardiovascular events and mortality.
Exposure to a hot environment triggers responses in the body, including increased blood flow, plasma volume, stroke volume, and heart rate, akin to cardiovascular exercise.
Hormone effects from hot environments can lead to shifts in cortisol levels, with a study showing a significant decrease in cortisol output after sauna sessions.
Controlling cortisol levels is crucial for managing stress, with methods like breath work and sauna exposure proving effective.
A specific sauna protocol involving 12-minute exposures to 90-degree Celsius followed by a cool-down break in cold water significantly lowers cortisol levels.
Heat shock proteins are activated in response to heat exposure, protecting proteins from misfolding and maintaining cellular health.
Heat shock proteins play a crucial role in longevity, with studies in animal models showing extended lifespan through heat exposure.
Sauna exposure upregulates FOXO3 levels, a molecule involved in DNA repair pathways and clearing senescent cells, potentially offsetting cardiovascular risks and mortality.
Individuals with hyperactive FOXO3 variants are more likely to live longer, but deliberate heat exposure can increase FOXO3 activity for others.
While the optimal sauna protocol for increasing FOXO3 activity is not yet clear, any deliberate heat exposure within the range of 80 to 100 degrees Celsius can impact various beneficial mechanisms in the body.

52:26

Optimizing Growth Hormone with Sauna and Cold

Sauna sessions should last between five to 20 minutes per session.
A study by Susanna Søberg found that 57 minutes of sauna exposure per week, along with 11 minutes of deliberate cold exposure, improves metabolism and increases brown fat.
To boost metabolism, aim for 11 minutes per week of cold exposure divided into multiple sessions and 57 minutes per week of sauna exposure.
Growth hormone is crucial for tissue repair and growth, and its secretion decreases with age.
Deliberate heat exposure through sauna can significantly increase growth hormone levels.
A study in 1986 showed that subjects in an 80-degree Celsius sauna for 30 minutes, four times a day, experienced a 16-fold increase in growth hormone.
The effects of sauna exposure on growth hormone decrease with more frequent exposure.
Heat exposure is a stressor to the body, similar to cold exposure, and can lead to adaptations that reduce the impact over time.
To maximize growth hormone increases, limit deliberate heat exposure to once a week or every 10 days.
Balancing heat exposure with cold exposure is essential for optimizing growth hormone release and overall health benefits.

01:05:28

Benefits of Cold and Heat Exposure

Norepinephrine, also known as noradrenaline, and dopamine levels increase significantly during brief cold water exposure, leading to improved mood, focus, and alertness.
Exposure to 16 degrees Celsius weather with minimal clothing for six hours can result in even greater increases in norepinephrine.
Short exposure to extreme cold or heat can stimulate heat shock proteins and growth hormone, while longer exposure to milder temperatures can also be beneficial.
Consult a doctor before attempting deliberate cold or heat exposure to ensure safety.
For heat exposure, temperatures of 80 to 100 degrees Celsius (176 to 212 degrees Fahrenheit) are recommended, with durations ranging from 5 to 20 minutes, increasing as tolerated.
Sauna sessions of three 20-minute sessions per week are suggested, preferably after a workout or in the evening.
Timing of sauna sessions should consider the body's circadian rhythm, with evening sessions potentially aiding in sleep.
Cold exposure late in the evening may increase body temperature, potentially affecting sleep, while early-day exposure aligns with natural temperature fluctuations.
Heat exposure, like sauna, is recommended later in the day to aid in cooling down the body for better sleep.
Hydrate adequately after sauna sessions, replacing lost water and electrolytes based on individual sweat rates and salt excretion. Aim for at least 16 ounces of water for every 10 minutes in the sauna.

01:17:09

Heat exposure boosts mood, mental health benefits.

Deliberate heat exposure can improve mood and mental health, not just cardiovascular effects or growth hormone levels.
Heat exposure enhances the brain's pathways for experiencing pleasure fully.
Endorphins, natural molecules in the brain and body, are released in response to stressors, like exercise.
Dynorphins, a type of endorphin, can make us feel worse in response to stressors and are released in hot environments.
Dynorphine binds to the CAPA receptor, triggering stress, agitation, and pain responses.
Over time, deliberate heat exposure leads to increased efficiency in feel-good endorphins, elevating mood levels.
Deliberate heat exposure can activate pathways that enhance joy and happiness in response to life events.
A study in 2018 found an inverse association between frequent sauna bathing and the risk of psychotic disorders.
Sauna protocols, done regularly, can improve cardiovascular and mental health, reducing cortisol levels.
Specific skin surfaces on the face, palms, and feet can be targeted for quicker heating or cooling to regulate core body temperature effectively.

01:30:23

"Skin Surfaces and Body Temperature Regulation"

Glabrous skin surfaces like palms, feet, and upper face have arteriovenous anastomoses (AVAs) that allow rapid heat or cold transfer to change core body temperature.
To cool off quickly, place cool towels on palms, feet, and face, ensuring they don't constrict veins; temperature depends on individual heat levels.
For hyperthermia, use frozen items like broccoli or blueberries on feet, hands, and face, avoiding ice packs; cool compresses on neck and head are beneficial.
Heating core body temperature efficiently involves warming feet, hands, and face with warm objects or fluids, not just covering with a blanket.
Fever is an adaptive response to kill pathogens; reducing fever with pills hinders the body's natural defense mechanism.
Local hyperthermia can convert white fat to beige fat, increasing metabolism; deliberate cold exposure can boost brown fat stores and core metabolism.
Local hyperthermia therapy involves heating skin to 41 degrees Celsius without damaging it, inducing UCP1 to increase mitochondrial function and convert white fat to beige fat.
UCP1 in beige fat generates heat in the body, aiding in metabolism; children have more brown fat for heat generation as they can't shiver.
Local hyperthermia triggers HSF1 binding to DNA, activating A2B1 to regulate glucose and lipid metabolism, leading to systemic increases in metabolism.
Local hyperthermia study in mice and humans showed conversion of white fat to beige fat, suggesting a potential method for fat loss and increased metabolism.

01:43:24

"Heat boosts metabolism and cell activity"

UCP1 increases mitochondrial function, leading to more ATP production and increased cell activity, resulting in higher metabolism.
Heat shock factor one and A2B1 play roles in lipid and glucose metabolism and regulation.
Spot reduction is not possible through local tissue heating, despite observed increases in beige fat cells in specific body areas.
Local skin heating may potentially increase the conversion of white to beige fat, boosting metabolism and improving glucose metabolism and thermogenesis.
The study involved equal numbers of males and females, following normal daily schedules and meals, with local hyperthermia therapy at 41 degrees for 20 minutes, three days per week for five weeks.
Mitohormesis describes how stressors like cold and heat activate pathways like UCP1, leading to increased metabolism and fat conversion.
Sauna or heat exposure for growth hormone benefits should be done less frequently but intensely, while cardiovascular and general health benefits may require more frequent sessions.
Mental health benefits from heat exposure can be maximized by getting slightly uncomfortable, aiding in dynorphin release for mood enhancement, with timing after workouts or in the evening for better sleep quality.

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