How cold should the water be for deliberate cold exposure, and for how long?

The water should be uncomfortably cold enough to induce a 'cold shock,' meaning your breathing is initially rapid and difficult to control. For optimal benefits, aiming for 1-2 minutes per session, totaling about 11 minutes per week, is sufficient without needing extreme cold temperatures.

What is the 'afterdrop,' and why does shivering sometimes occur after leaving cold water?

The 'afterdrop' is when your core body temperature continues to decrease even after getting out of cold water. This happens because blood vessels, which constricted in the cold to protect core organs, dilate upon exit, allowing cooled surface blood to flow back to the core, inducing shivering.

What are the long-term health benefits of regular cold exposure?

Long-term benefits include improved insulin sensitivity and glucose balance, lower blood pressure, lower heart rate, increased brown fat activation and density, and reduced inflammation, contributing to a lower risk of lifestyle diseases like type 2 diabetes and neurological conditions like Alzheimer's.

How does brown fat get activated, and can adults increase their amount of brown fat?

Brown fat is activated rapidly by cold exposure on the skin, sending signals to the hypothalamus and directly to the fat itself. Yes, adults can increase their brown fat density and distribution through consistent cold exposure, such as sleeping in cooler rooms (e.g., 19°C) or taking cold showers.

What are the optimal times for sauna use to achieve health benefits?

Studies suggest that 10-15 minutes per sauna session, totaling around 57 minutes per week, is sufficient to gain significant health benefits like reduced cardiovascular disease risk, aligning with the hormetic stress principle.

What is the 'Søberg Principle' and why is it important?

The 'Søberg Principle' refers to ending cold/heat cycles on cold. This forces the body to rewarm itself naturally, keeping brown fat and muscles activated for hours, boosting metabolism, improving neural transmitter function, and promoting a more efficient heating and cooling system.

Are there any risks or things to avoid during cold exposure, like head submersion?

Submerging the head significantly increases heat loss from the core (36% more than neck-deep immersion), bringing one closer to hypothermia and potentially causing dizziness or 'brain freeze.' It's often recommended to keep the head out or use a cap.

Are cold exposure protocols different for children or women compared to men?

Children, being smaller in mass, have less capacity to defend their core temperature and are at higher risk of hypothermia, so their exposure time should be greatly reduced (e.g., ~1 minute). While women generally have more brown fat, the brief micro-stressing protocols appear safe and effective for both genders, though specific protocols for women may require further study.

Can cold exposure help with conditions like Raynaud's syndrome?

While logically, cold and heat exposure could improve vascularity for conditions like Raynaud's syndrome, specific directed studies are needed. Anecdotal evidence is mixed, and individuals with such conditions may benefit from keeping hands/feet out of the coldest water or using protective gear like neoprene boots.

Does it matter if I do deliberate cold exposure in a fed or fasted state?

There is no specific scientific literature or studies mentioned in the discussion specifically comparing the benefits of deliberate cold exposure in a fed versus fasted state.

What role do cultural practices, like Scandinavian winter swimming, play in health?

Scandinavian cultures have long-standing traditions of winter swimming and exposing babies to cold, which intuitively align with the benefits of cold adaptation and boosting the immune system. These cultural norms foster resilience and activate brown fat from a young age.

Key Moments

How to Use Cold & Heat Exposure to Improve Your Health | Dr. Susanna Søberg

Andrew Huberman

Science & Technology4 min read151 min video

May 15, 2023|739,744 views|13,113|1,084

andrew huberman huberman lab podcast huberman podcast dr. andrew huberman neuroscience huberman lab andrew huberman podcast the huberman lab podcast science podcast Susanna Søberg Susanna Soberg cold exposure

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Key Moments

TL;DR

Deliberate cold & heat exposure improve metabolism, brain health, and inflammation. Key is hormetic stress, with short, frequent sessions.

Key Insights

Deliberate cold and heat exposure activate the sympathetic nervous system, releasing catecholamines like dopamine and epinephrine, impacting mood and metabolism.

Cold shock response, characterized by involuntary gasping and increased breathing rate, can subside with adaptation, building resilience.

Brown fat activation is a key mechanism. Cold on the skin signals the hypothalamus, leading to norepinephrine release that activates brown fat.

Shivering, though uncomfortable, is beneficial as it increases metabolism and burns calories, contributing to improved insulin sensitivity.

Short, frequent cold/heat exposures (around 1-2 minutes cold, 10-15 minutes heat per session, totaling ~11 mins cold and ~57 mins heat per week) are more beneficial than long, infrequent sessions for hormetic stress.

Ending cold or heat exposure on cold ("Søberg Principle") forces the body to heat itself up, extending metabolic and neurotransmitter activation.

Exposure can decrease inflammation, improving insulin sensitivity, blood pressure, and potentially mitigating risks of lifestyle diseases and mental health conditions.

Physiological cascade of cold exposure

Deliberate cold exposure, whether through cold showers or immersion, triggers a potent response in the sympathetic nervous system. This leads to the release of catecholamines such as epinephrine and norepinephrine, which significantly impact metabolism and mood. The initial cold shock response, characterized by involuntary gasping and hyperventilation, is a natural reaction that can be managed and reduced with regular adaptation, building resilience over time. This physiological stress, when controlled, acts as a hormetic stressor.

The role of brown fat activation

Cold receptors on the skin send signals to the hypothalamus, initiating a cascade that activates brown adipose tissue (BAT). This 'brown fat' is crucial for thermogenesis, the body's process of generating heat and increasing metabolism. There are multiple pathways for this activation: direct signaling from skin receptors to brown fat, indirect signaling via norepinephrine release in the brain, and even through muscle shivering. Brown fat's ability to utilize glucose and fatty acids from the bloodstream means it plays a role in metabolic health. Consistent cold exposure can increase brown fat density and efficiency.

Benefits of shivering and metabolic improvements

Shivering, often perceived as an undesirable reaction to cold, is a vital metabolic process that burns calories and increases heat production. It is a signal that the body is engaging its thermogenic capacity, primarily through muscle activity. This process, along with brown fat activation, contributes to improved insulin sensitivity and glucose metabolism. Regular cold exposure can lead to long-term adaptations like lower blood pressure, reduced heart rate, and better glucose clearance, potentially preventing lifestyle-related diseases.

The hormetic principle: Thresholds and frequency

The key to harnessing the benefits of cold and heat exposure lies in 'hormetic stress' – exposing the body to a manageable stressor to promote adaptation. Research suggests that short, frequent exposures are more effective than prolonged ones. For cold exposure, this typically means 1-2 minute intervals, totaling around 11 minutes per week. Similarly, for heat exposure (sauna), sessions of 10-15 minutes, totaling about 57 minutes weekly, appear optimal. Overdoing these exposures can be counterproductive, leading to cellular exhaustion rather than adaptation.

The 'Søberg Principle' and the importance of ending on cold

A crucial protocol identified is to 'end on cold,' termed the 'Søberg Principle.' Finishing deliberate cold exposure sessions with cold, rather than immediately warming up, forces the body to generate its own heat. This prolonged internal heating process requires sustained activation of brown fat and muscles, effectively extending the metabolic benefits and neurotransmitter release far beyond the initial exposure. This continuous metabolic work can enhance cellular efficiency and the body's ability to regulate temperature over time.

Reducing inflammation and broader health impacts

Beyond metabolic improvements, cold and heat exposure demonstrably lower inflammation markers like IL-6 and IL-10. This reduction in systemic inflammation is critical for preventing a range of chronic diseases, including type 2 diabetes, cardiovascular disease, and neurodegenerative conditions like Alzheimer's. By engaging these natural stressors, the body can reset its homeostasis, repair cells, and build resilience, counteracting the negative effects of modern sedentary lifestyles and chronic heat-comfort.

Practical application and individual differences

While the science is compelling, practical application requires individual consideration. Factors like personal tolerance, adapting to cold, and the specific type of exposure (showers, immersion, saunas) matter. Children and individuals with certain conditions may need modified protocols due to differences in physiological response and heat loss. Consistent exposure, varying temperatures, and listening to one's body are key to safely and effectively integrating these practices for long-term health benefits. Using accessories like neoprene booties or keeping hands out of the water can be acceptable adaptations if pain is a barrier.

Mentioned in This Episode

●Supplements

●Products

●Companies

●Organizations

●Books

●Studies Cited

●Concepts

●People Referenced

Cold & Heat Exposure Protocols for Health

Practical takeaways from this episode

Do This

Submerge into uncomfortably cold water (up to the neck) for 1-2 minutes per session.

Aim for a total of 11 minutes of cold exposure per week, spread across 2-3 sessions.

Use sauna for 10-15 minutes per session, aiming for 57 minutes total per week.

End deliberate cold/heat sessions on cold to force the body to heat itself up naturally, enhancing metabolism and neurotransmitter activation (Søberg Principle).

Expose yourself to varied temperatures; any cold stimulus, even cold air or sleeping in a 19°C room, can activate brown fat.

Embrace shivering as a healthy stressor that trains cells and boosts metabolism.

Consider using neoprene boots or keeping hands out of the water if pain in extremities is a barrier.

For children, limit cold exposure time due to smaller body mass and higher risk of hypothermia (e.g., about 1 minute).

Avoid This

Avoid long durations in cold water (e.g., 20-30 minutes), as this can exhaust cells and be detrimental.

Do not exceed ~30 minutes per sauna session, as benefits plateau and can become overstressing.

Do not try to become overly 'cold adapted' to the point where the stimulus is no longer jarring, as the hormetic stress response may diminish.

Avoid immediate warm showers or saunas after cold exposure if the goal is to maximize metabolic and neurotransmitter benefits from natural rewarming.

Do not ignore signs of hypothermia, especially in children or smaller individuals.

Do not solely rely on consistent exact temperatures; vary them to keep the body's adaptive systems active.

Recommended Weekly Cold & Heat Exposure Thresholds

Data extracted from this episode

Exposure Type	Duration per Session	Total Duration per Week	Number of Sessions per Week
Deliberate Cold Exposure (water)	1-2 minutes	11 minutes	2-3
Sauna (heat exposure)	10-15 minutes	57 minutes	2-3 (with cold alternation)

Heat Loss Rate: Head Submersion vs. Neck Deep

Data extracted from this episode

Immersion Type	Heat Loss from Core
Submerged up to the neck	11%
Head also submerged	Additional 36% (total 47%)

Average Water Temperatures in Danish Winter

Data extracted from this episode

Month	Average Water Temperature (°C)
October	~12°C
January (coldest)	2-4°C

Common Questions

Upon entering uncomfortably cold water, the sympathetic nervous system activates, leading to a cold shock response, increased heart rate, and release of catecholamines like dopamine, epinephrine, and norepinephrine. This process is immediate and also activates brown fat.

Topics

Sleep Optimization Cold Exposure Health & Longevity Neuroscience & the Brain Human Performance Sauna Benefits Blood Pressure Brown Fat Dopamine Pathways Insulin Sensitivity Heat Exposure Stress Adaptation Immune System Modulation

Mentioned in this video

People

Susanna Søberg

Guest on the podcast and lead researcher on a seminal study about deliberate heat and cold exposure for enhancing human metabolism and increasing brown fat thermogenesis. Authored the book Winter Swimming.

Wim Hof

Known for popularizing cold thermogenesis practices, mentioned in the context of the growing interest in cold exposure.

Peter Attia

An expert in longevity and health span, who highlighted the critical importance of blood pressure control for overall health and preventing cardiovascular disease.

Andrew Huberman

Host of the Huberman Lab podcast and a professor of neurobiology and ophthalmology at Stanford School of Medicine, who has a long-standing interest in cold thermogenesis.

Craig Heller

A Stanford biology department colleague of Andrew Huberman who researches cold and its impact on physiology and sports performance.

Books

Cell Reports Medicine

The journal that published Dr. Søberg's research on deliberate heat and cold exposure protocols for improving metabolism and human health.

Winter Swimming

A book authored by Dr. Susanna Søberg that breaks down deliberate heat and cold exposure, cold acclimation, cold shock response, dangers, benefits, and specific protocols.

Companies

Plunge

A self-cooling cold plunge unit for deliberate cold exposure, which Andrew Huberman has used and recommends for its ease of use and powerful cooling filtration.

Inside Tracker

A personalized nutrition platform that analyzes blood and DNA data to help users understand their body and reach health goals, now including new hormone markers for women.

Athletic Greens

A vitamin, mineral, and probiotic drink for foundational nutritional needs, taken by Andrew Huberman since 2012 for gut health and overall nutritional support.

Concepts

Hypothalamus

The temperature-regulating center in the brain that receives signals from cold receptors in the skin to activate brown fat for thermogenesis.

Raynaud's syndrome

A condition characterized by very poor blood flow to the extremities, leading to cold fingertips and potential discoloration, for which the applicability of cold exposure is questioned.

Studies & Research

Lightner et al. 2017

A study that created overlay maps of where brown fat is located and how it can grow or decrease in the body, demonstrating its plasticity.

Hansen et al. 2017

A study showing that subjects who slept in a 19°C room for one month increased their insulin sensitivity and brown fat, while those sleeping in warmer rooms showed decreased activation.

Laukanen et al. 2015

An observational study from the Finnish cohort that demonstrated sauna use, up to 30 minutes, lowered the risk of cardiovascular disease, with a dose-response up to 19 minutes.

Organizations

Spa 88

A Banya located on Wall Street in New York, described as an amazing facility where patrons are always clothed.

Rigshospitalet

A hospital in Denmark associated with studies showing decreased blood flow to the brain when submerging in cold water.

University of Copenhagen

Where Dr. Susanna Søberg completed her doctoral thesis work at the center of inflammation and metabolism and the center for physical activity research.

Archimedes Banya

A Russian Banya in San Francisco with hot sauna and cold plunge that is clothing optional and co-ed on most days.

Drugs & Medications

epinephrine

A neurotransmitter (adrenaline) that belongs to the catecholamines, strongly impacting mood and metabolism; its production is affected by cold and heat exposure.

Products

Maui Nui Venison

A nutrient-dense red meat from USDA certified wild-harvested deer on Maui, which also produces bone broth with high protein content, touted as a sustainable source of quality protein.

Thesis

A company that creates custom nootropics designed to enhance specific mental states like focus, creativity, or clarity, based on a quiz to personalize starter packs.

Supplements

Succinate

A molecule mentioned in relation to shivering, which is thought to activate brown fat.

Momentous Supplements

A supplement company partnered with the Huberman Lab Podcast, offering products for sleep, focus, and hormone support.