Heat exposure has profound effects on our biology, including improving brain function and metabolism. Local heating can change the identity of certain fat cells, potentially impacting metabolism and aiding in weight loss. Deliberate heat exposure, such as sauna use, has been shown to reduce mortality rates from cardiovascular events and all-cause mortality. It can also lower cortisol levels, improve mental health, and activate heat shock proteins. The timing of heat exposure is important for optimizing its benefits, with sauna sessions recommended in the second half of the day or before sleep. Hydration is crucial during sauna use, and deliberate heat exposure can also improve sleep and body temperature regulation. Heat exposure stimulates the release of growth hormone, with the best time for sauna use being in the evening or at nighttime. Deliberate heat exposure can also improve mood and mental health by upregulating pleasure pathways in the brain. Cooling specific areas of the body, such as the palms and soles, can help cool off the core body temperature quickly. Local hyperthermia therapy has the potential to convert white fat to metabolically active beige fat. Heat and cold exposure can increase metabolism and improve overall health and longevity.
Heat & Health
Heat has a profound effect on our biology, impacting our metabolism and cognition. Properly applied heat can improve brain function. The science of heat and heating, including the use of tools like saunas, is discussed. Local heating can also be used to heal and improve tissues. A recent study published in the journal Cell shows that heating up skin and fat can change the identity of certain fat cells, potentially impacting metabolism. Heat exposure can increase the conversion of white fat to beige fat, which is metabolically active and helps burn off more white fat. This finding has emerged from studying the biology of burns and has led to the development of tools to combat obesity and metabolic disorders.
The Brain-Body Contract
The Brain-Body Contract is a lecture series hosted by Andrew Huberman, discussing science and science-based tools. The series covers both familiar and new topics, with a focus on the brain and body connection. The events include a question and answer period for audience engagement. Tickets for the live events in Seattle and Portland are available on hubermanlab.com/tour.
- Lecture series hosted by Andrew Huberman
- Covers science and science-based tools
- Focuses on the brain and body connection
- Includes question and answer period for audience engagement
- Live events in Seattle and Portland
- Tickets available on hubermanlab.com/tour
Body Shell Temperature vs. Body Core Temperature
The human body has two distinct temperatures: the temperature on the skin (shell) and the temperature of the core (organs, nervous system, spinal cord). The brain constantly regulates these temperatures based on the external environment. Neurons release chemicals to heat up or cool down the body as needed. Understanding these temperatures is important for understanding the body's response to heat and cold.
Key points:
- The body has two temperatures: one on the skin and one in the core.
- The brain regulates these temperatures based on the external environment.
- Neurons release chemicals to heat up or cool down the body.
- Cooling down the surface can heat up the core, while being in a hot environment triggers mechanisms to cool down the body.
- Understanding the effects of heat on both the shell and core is crucial for designing effective protocols for heat exposure.
- Heat should be understood as a process, not just a static concept, to improve biology, health, and performance.
Thermal Regulation, Hyperthermia
Thermal regulation and hyperthermia are the main topics discussed in the summaries. The key points include:
- A specific sauna protocol can increase the release of growth hormone in the brain and body by 16 fold.
- Transitioning between hot and cool environments repeatedly over a short period of time is crucial for this increase in growth hormone.
- Simply staying in a sauna for a long time without temperature transitions will not produce the same effect.
- Sauna and other heat-related tools can improve metabolic health, control cortisol, and positively impact mental health.
- The mechanisms of heating and cooling will be explained in a clear way, even for those without a background in biology.
- Understanding the importance of both the shell and core of the body is crucial for optimizing biology using heat-related tools.
- The science of heat and cold has been studied for over a hundred years.
- Thermal regulation has gained significant interest in various fields including neuroscience, mental health, and health optimization.
- Caution must be exercised when heating up the body, as excessive heat can cause neuron damage in the central nervous system.
- Hyperthermia should be avoided, and ways to rapidly protect against it will be discussed.
- Pregnant women, nursing mothers, and individuals sensitive to hot environments should avoid saunas and similar heat-related tools, unless advised otherwise by a doctor.
- It is important to approach any heating-related methods with caution and gradually increase the temperature if necessary.
Heat Removal Circuits, Pre-Optic Hypothalamus (POA)
The Pre-Optic Hypothalamus (POA) is a key component of the heat removal circuits in the body. These circuits involve neurons in the skin, brain, and body that communicate with each other. The POA receives signals from the lateral parabrachial area and activates various heat-dissipating responses in the body. It can also influence behavior and activate the sympathetic nervous system. Understanding these circuits is important for regulating body temperature and utilizing tools related to heating.
Protocols & Benefits of Deliberate Heat Exposure
Deliberate heat exposure, such as sauna, has been shown to improve health and longevity. Studies have demonstrated that regular use of sauna can reduce mortality from cardiovascular events and other causes. The recommended temperature range for heat exposure is between 80 to 100 degrees Celsius (176 to 212 degrees Fahrenheit), with a duration of 5 to 20 minutes per session. Going into the sauna 2 to 3 times per week can lower mortality rates from cardiovascular events, and those who go 4 to 7 times per week have an even lower risk. Sauna use has also been linked to a reduction in all-cause mortality. Incorporating deliberate heat exposure into one's routine, starting at 2 to 3 times per week, can have positive impacts on overall health.
Tools & Conditions for Deliberate Heat Exposure
Deliberate heat exposure, such as sauna use, can have impressive health benefits. It is not necessary to use a sauna specifically, as long as your shell and core heat up properly. There are various ways to create a hot environment, including saunas, hot tubs, or simply cranking up the heat in a room. Moving around and wearing a lot of clothing can also increase shell and core temperature. Saunas are a convenient option for research studies due to their controlled and uniformly hot environment.
- Deliberate heat exposure can be achieved through various methods such as saunas, hot tubs, or wearing a lot of clothing.
- The recommended temperature range for heat exposure is between 80 and 100 degrees Celsius.
- Sauna sessions should last between five to 20 minutes.
- Infrared saunas may not reach the optimal temperature range, but they can still provide benefits.
- It is important to be cautious and avoid excessive hyperthermia or overheating.
- The choice of tool or sauna depends on individual circumstances, budget, and accessibility.
Deliberate Heat Exposure, Cortisol & Cardiovascular Health
Deliberate heat exposure, such as sauna sessions, has various health benefits, including reducing the risk of cardiovascular events and all-cause mortality. It activates neurons in the preoptic area, leading to vasodilation and increased blood flow. Heat exposure also causes hormonal shifts, affecting the output of hormones from various glands. A study on young adult men showed positive endocrine effects from repeated hot thermal stress and cold water immersion.
Specifically, saunas have been found to lower cortisol levels, a stress hormone. Participants exposed to saunas at high temperatures experienced a decrease in cortisol output, which is beneficial for managing acute and long-term stress. This research is relevant for individuals with high stress levels.
A protocol of 12-minute exposures to a hot environment followed by a cool down break has been found to significantly lower cortisol levels. This low-cost method can be achieved through hot and cold water contrast or hot weather and a cool shower. While this protocol did not impact other hormones significantly, there are other sauna protocols that can. Overall, deliberate heat exposure is a potentially useful method for reducing stress and improving cardiovascular health.
Heat Shock Proteins (HSPs), Molecular Mechanisms of Heat Regulation
Heat shock proteins (HSPs) are activated in response to heat stress and play a crucial role in protecting the brain and body by preventing protein misfolding. Activation of HSPs through deliberate heat exposure has been shown to extend lifespan in model organisms. Studies on humans also suggest the benefits of deliberate heat exposure. However, prolonged activation of HSPs can have negative effects. Sauna exposure is one way to activate HSPs.
Longevity & Heat Exposure, FOXO3
Deliberate heat exposure, such as sauna use, can increase the activity of FOXO3, a gene associated with longevity. Individuals with additional copies or hyperactive versions of FOXO3 are more likely to live to 100 years or longer. For those without these genetic variations, deliberate heat exposure can still increase FOXO3 activity. The optimal sauna protocol for increasing FOXO3 is not yet clear, but any deliberate heat exposure is likely to impact other beneficial mechanisms such as reducing cortisol and activating heat shock proteins. A rough guide for sauna use is a temperature range of 80 to 100 degrees Celsius and a duration of five to 20 minutes per session.
Deliberate Cold & Heat Exposure & Metabolism
Deliberate heat and cold exposure can improve metabolism and increase brown fat in the body. The recommended threshold is 57 minutes of sauna exposure and 11 minutes of cold exposure per week. This can be divided into multiple sessions. The Søberg Protocol suggests 11 minutes of cold exposure and 57 minutes of sauna exposure per week. Sauna sessions can also decrease cortisol levels and increase heat shock proteins.
Deliberate Heat Exposure & Growth Hormone
Deliberate heat exposure, specifically through sauna use, can significantly increase growth hormone levels in the body. This has implications for muscle growth, fat loss, exercise recovery, and injury repair. However, the frequency of sauna sessions has an inverse relationship with the magnitude of growth hormone increase, as the body adapts to the stress over time. To trigger significant increases in growth hormone, it is important to limit deliberate heat exposure to once a week or less, and time it with other events such as hard workouts or fat loss goals.
Parameters for Heat & Cold Exposure
The most profound aspect of the text is that in order to design the optimal protocol for deliberate heat exposure, it is important to consider the effects of cold exposure.
- Cold exposure increases norepinephrine and dopamine levels, leading to improvements in mood, focus, and alertness.
- Longer exposure times are required for cold exposure compared to heat exposure.
- Brief exposures to heat or cold can stimulate heat shock proteins and growth hormone.
- The recommended temperature range for heat exposure is 80 to 100 degrees Celsius (176 to 212 degrees Fahrenheit).
- The duration of heat exposure can range from five to 30 minutes, depending on individual goals.
- The choice of wet sauna, dry sauna, hot shower, or hot bath depends on personal preference and accessibility.
- The purpose of the video is to provide an understanding of the underlying mechanisms and general parameters for achieving desired results.
- The speaker personally follows a protocol of three 20-minute sauna sessions per week, usually after a workout.
Circadian Rhythm & Body Temperature, Cold & Heat Exposure
The circadian rhythm of body temperature is crucial for our sleep-wake cycle. Cortisol levels rise in the morning as body temperature gradually increases. In the afternoon, body temperature peaks and then starts to drop, signaling the body to prepare for sleep. Sauna or cold exposure can affect body temperature, so timing is important, especially for those struggling with sleep. Cold exposure should be done early in the day to match the natural increase in body temperature, while deliberate heat exposure, like using a sauna, should be done later in the day. Many find it easier to fall asleep after a sauna session in the later half of the day, as body temperature drops.
Heat Exposure & Growth Hormone
Heat exposure, such as sauna sessions, can stimulate the release of growth hormone. The best time to do sauna for maximum growth hormone release is in the evening or at nighttime, especially if you haven't eaten in the two hours before sleep. It is important to rinse off the sweat from the sauna with a warm or cool shower before sleep. Keeping glucose and insulin levels low in the bloodstream can enhance growth hormone release, as elevated levels of these hormones tend to reduce it. A study showed that combining sauna with low blood sugar or exercise can further increase growth hormone release. However, repeating sauna sessions in a short period of time may not yield the same level of growth hormone increase.
- Sauna sessions can stimulate the release of growth hormone
- Best time for sauna is in the evening or at nighttime, especially if you haven't eaten in the two hours before sleep
- Rinse off sweat from sauna with warm or cool shower before sleep
- Low glucose and insulin levels enhance growth hormone release
- Combining sauna with low blood sugar or exercise can further increase growth hormone release
- Repeating sauna sessions in a short period of time may not yield the same level of growth hormone increase
Heat exposure, specifically through sauna use, can stimulate the release of growth hormone. However, it is important to note that the release of growth hormone is reduced if it has already been released earlier in the day. To maximize the release of growth hormone in response to sauna use, it is recommended to do it on an empty stomach or at least a few hours after eating. The timing of sauna use in relation to meals and sleep should be considered to optimize growth hormone production. However, it is not necessary to obsess over the exact conditions, as regular sauna use a few times a week can still provide numerous health benefits.
- Sauna use stimulates the release of growth hormone
- Growth hormone release is reduced if it has already been released earlier in the day
- Sauna should be done on an empty stomach or a few hours after eating to maximize growth hormone release
- Timing of sauna use in relation to meals and sleep should be considered for optimal growth hormone production
- Regular sauna use a few times a week provides numerous health benefits
Deliberate heat exposure, such as sauna use, can have positive effects on sleep and body temperature regulation. It can aid in the transition to sleep and promote decreases in body temperature. Therefore, it is recommended to schedule sauna sessions in the second half of the day, and possibly even before sleep, to maximize these benefits.
- Sauna use aids in the transition to sleep and promotes decreases in body temperature
- Schedule sauna sessions in the second half of the day or before sleep to maximize sleep and body temperature regulation benefits
Tool: Hydration & Sauna
Hydration is crucial when using a sauna as water loss occurs through sweating. To maintain proper hydration, it is advised to consume at least 16 ounces of water for every 10 minutes spent in the sauna, considering individual factors like sweat rate and salt excretion. Additionally, deliberate heat exposure offers various health advantages.
Heat, Endorphins & Dynorphins, Mood
Deliberate heat exposure, such as sauna use, can improve mood and mental health by upregulating pleasure pathways in the brain and body. This is due to the release of endorphins, which alleviate pain and induce euphoria. However, heat exposure also triggers the release of dynorphins, which initially cause discomfort. Over time, this discomfort leads to increased efficiency in the feel-good endorphin system, resulting in an elevated baseline mood and heightened happiness. Heat exposure can also leverage the dynorphin system to improve mental health and reduce the risk of psychotic disorders. Overall, deliberate heat exposure has benefits for metabolism, cardiovascular function, and mental well-being.
Tool: Glabrous Skin To Heat or Cool
This video discusses the deliberate heating or cooling of specific parts of the body, such as the palms of the hands, the bottoms of the feet, and the upper half of the face. These areas have specific types of vasculature that allow heat and cold to move quickly. The ability to cool off the core of the body quickly can be beneficial and even life-saving in cases of hyperthermia. The video also mentions the dangers of overheating and provides tools for cooling off the core.
- Glabrous skin areas (palms, soles, and upper face) have vasculature that allows for quick heat and cold transfer.
- Cooling these areas can help cool off the core body temperature quickly.
- Cool towels or frozen items can be used on glabrous skin areas to cool the body.
- Warm objects or fluids can be used on glabrous skin areas to warm the body.
- Targeting glabrous skin areas is more effective than applying cold compresses to the torso.
- Deliberate heat exposure can have various health benefits.
- Fever is a natural mechanism to kill pathogens, but hyperthermia should be prevented.
Local Hyperthermia, Converting White Fat to Beige Fat, Metabolism
Local hyperthermia therapy has the potential to convert white fat to beige fat, which is a metabolically active form of fat. This therapy involves heating a specific patch of skin without causing damage. A recent study found that heating the skin to 41 degrees Celsius can induce browning of white fat and treat obesity. Beige and brown fat cells act as a fuel source that can be burned to generate heat in the body. Deliberate cold exposure and local heating of skin tissue can both induce the conversion of white fat to beige fat. This conversion leads to increased metabolism throughout the body. However, more controlled studies are needed to fully understand the effects of local hyperthermia on fat conversion.
Hormesis/Mitohormesis & Heat/Cold Exposure
Hormesis and Mitohormesis & Heat/Cold Exposure:
- Hormesis is subjecting oneself to enough stress to induce adaptation.
- Mitohormesis involves activating certain pathways to induce changes in mitochondria and increase metabolism.
- Heat and cold exposure can lead to increased metabolism and conversion of white fat to beige fat.
- Both heat and cold exposure activate specific cellular pathways that promote cellular repair and adaptation.
- Heat exposure improves cardiovascular function, insulin sensitivity, and cognitive function.
- Cold exposure increases calorie burning and improves immune function.
- Deliberate heat and cold exposure can be a powerful tool for improving health and longevity.
Benefits of Heat Exposure
Heat exposure, such as sauna sessions, can activate certain biological pathways in the body.
Key points:
- Sauna should be done infrequently, about once per week, with multiple sessions in one day, to maximize growth hormone increases.
- For cardiovascular and potential longevity benefits, sauna should be done three to four times per week, or even daily.
- For general health effects, about an hour per week of sauna broken up into three sessions is recommended.
- To access mental health benefits, it is best to get a little uncomfortable in the heat environment, as this increases dynorphin levels and enhances the positive effects of endorphins on mood.
- Sauna after a workout or in the later part of the day is most beneficial for sleep.
- The post-sauna cooling effect is also important for sleep.
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