Summary of Huberman Lab Podcast Episode: Dr. Susanna Søberg: Enhancing Health with Cold & Heat Exposure
Podcast: Huberman Lab
8 min. read
— Description —
Discover the incredible benefits of deliberate cold exposure on your health and metabolism Learn how activating brown fat through cold exposure can improve blood pressure, insulin sensitivity, and heart rate Find out the optimal cold and heat dose for maximum results and how to overcome trouble tolerating cold exposure
Dont miss out on the long-term benefits of this powerful stressor.
Dr. Susanna Søberg: Enhancing Health with Cold & Heat Exposure
Table of contents
Key Takeaways
- Any cold exposure to the skin that you register as jarring or uncomfortable activates brown fat, increasing metabolism
- Tip: don’t worry so much about the specific temperature, think more about the difference in temperature between your skin and the water
- After drop: blood vessels constrict in the cold to keep organs healthy; once you get out of the cold, blood vessels dilate again but the surface is still cold so core body temperature drops and induces a shiver
- Cycling heat and cold? End on cold for best results
- “Cold is the most potent stressor activator of brown fat.” – Dr. Susanna Søberg
- People who work outside (e.g., farmers) or were more active earlier in life will maintain higher levels of brown fat after age 40
- Long-term benefits of deliberate cold exposure: lower blood pressure, improve insulin sensitivity, improve metabolism, improve heart rate, better glucose balance
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Cold & heat dose for optimal results: cold exposure 11 minutes per week, spread out across 2-3 sessions + 10-15 minutes per session (up to 30 minutes per week)
- The goal is to keep the stimulus, a stimulus – you don’t want to build up the ability to hang out in cold for 11 minutes or sauna for an hour
- There is a tipping point at which a good, hormetic stressor can feel like chronic stress to the body and you no longer receive additional healthy outcomes
- Trouble tolerating cold exposure? You will still get all the benefits if you leave your hands out of the water, wear a cap and submerge up to the neck, and/or wear booties on your feet
Introduction
- Dr. Susanna Søberg, Ph.D. (@SusannaSberg1) is the founder of “Soeberg Institute” and “The Thermalist cure”. Susanna is a leading international scientist and expert in cold and heat therapy to reduce stress and improve health, and sleep and optimize performance. Her research focuses on the effects of deliberate cold and deliberate heat exposure on metabolism and other aspects of human physiology.
- Andrew Huberman and Susanna Søberg discuss how deliberate heat and cold can improve metabolism, cardiovascular and brain health, balance hormones, and decrease inflammation. Dr. Søberg reviews how to leverage specific protocols depending on goals, how to apply various types of heat and cold exposure and other actionable tools.
- Host: Andrew Huberman (@hubermanlab)
What Happens In The Body When We Get Cold?
- If you are hot before entering cold, you will have an easier time than if you were cold beforehand
- It’s difficult to put a precise temperature on “cold” because it is really more dependent on the difference between the current temperature of your skin and the temperature of the water
- Tip: instead of a specific temperature, focus on uncomfortably cold (but safe)
- You can train and adapt to cold exposure so shock subsides but it should be hard
- People vary tremendously in ability to embrace the cold – the more you resist it, the worse it’ll feel for you
- The more you cover your body in cold water, the more potent activation of cold receptors on the skin
- Even being outside in cold air will increase norepinephrine and activate brown fat which increases metabolism
- We know that as soon as our skin is cold, brown fat is activated – but we don’t have all the nuances of shower vs cold air, etc. for metabolism
- Two tissues increase thermogenesis: brown fat and muscles (shivering)
- Dive reflex: survival system which slows down oxygen response in the body, activation of the sympathetic nervous system after 1-2 minutes
Importance Of Shiver
- Shivering increases metabolism in the body
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After drop: sometimes shivering occurs once you’re already out of the cold
- When you get in the cold, your blood vessels will constrict because you want to keep vital organs warm but they’ll open again once you’re out
- Shivering is an autonomic response but shouldn’t be avoided – like exercise, shivering is training your cells to healthy stressors
- Perception of cold doesn’t always correlate to shivering
Long-Term Benefits & Adaptations Of Cold Exposure
- As soon as you go into cold there’s an activation of brown fat
- Every time you are exposed to cold, you’ll build adaptation – you’ll have more brown fat activated and will heat up faster because your body gets more efficient
- Stress response will subside with consistent exposure so catecholamines will increase less
- Insulin sensitivity will improve and metabolism will increase as a result
- Other benefits: lower blood pressure, improved heart rate, better glucose balance
Diving Deeper Into the Biology Of Brown Fat
- Brown fat: fat located around the organs
- Brown fat is more widespread throughout the body than originally thought
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Pathway from cold receptors to brown fat: cold receptors send a signal to the hypothalamus which increases noradrenaline which activates brown fat
- Interestingly, brown fat is also activated when we get warmth on our skin
- Brown fat is essential to our survival and evolution because temperature regulation is critical
- Brown fat is elastic, it can grow and increase if there’s an increase in noradrenaline (but we want this within certain confines)
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After age 40 people have less brown fat and obesity increases; the linearity of the relationship isn’t clear but both things exist
- If you moved a lot in your early years and throughout life, you will keep more of your brown fat later in life
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Ways to ease into cold exposure for brown fat activation and insulin sensitivity: sleeping in a very cold room (32F), dipping a hand in cold water, exposure to cold air
- Some Scandinavian countries have infants and children sleep outside in the cold in the winter to cold adapt
- Women have more brown fat than men and physiologically run colder than men
Søberg’s Landmark Study
- Was interested in potent cold exposure as proof of concept study
- Participants: started as an observational study on male winter swimmers who swam 2-3 seasons
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Method: participants stayed in cold water up to the neck for 1-2 minutes x 2-3 per week
- Cold-heat cycling: participants start in a cold, go to a sauna (176F 10-15 minutes), and end in cold
- Regular PET scans were taken to monitor brown fat
- Monitoring of comfortability in cold was conducted
- Results: winter swimmers produced less insulin and faster glucose clearance on all experimental days
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Conclusion: cold exposure 11 minutes per week, spread out + 10-15 minutes per session (up to 30 minutes per week)
- Inflammation biomarkers improved which can have a huge impact on disease
- Interestingly, one participant didn’t have any brown fat
- Regrettably, measurements of sleep were not assessed but anecdotally sleep seemed to improve
- Note, it doesn’t matter whether you are wearing a bathing suit or nude during cold exposure
Other Topics Related To Deliberate Cold Exposure
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Cold exposure can’t be translated directly to children because they are smaller in mass
- In one study, boys could tolerate for about 1 minute but could become hypothermic beyond
- It’s possible protocols may be different for men and women but more studies are needed
- It’s possible there are therapeutic benefits for those with autoimmune conditions but more studies need to be done – it is enough to be submerged up to the neck
- Time of day and fasting state is unlikely to have an effect on cold exposure outcomes
- Dr. Jack Kruse had a lot of thoughts about this episode – check out his critique here
Articles
- Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men (Cell Reports Medicine)
- Human physiological responses to immersion into water of different temperatures (European Journal of Applied Physiology)
- Variations in leptin and insulin levels within one swimming season in non-obese female cold water swimmers (Scandinavian Journal of Clinical and Laboratory Investigation)
- Mapping of human brown adipose tissue in lean and obese young men (Proceedings of the National Academy of Sciences)
- A role for brown adipose tissue in diet-induced thermogenesis (Nature)
- Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events (JAMA Internal Medicine)
- Impact of cold exposure on life satisfaction and physical composition of soldiers (BMJ Military Health)
- Thermal effects of whole head submersion in cold water on nonshivering humans (Journal of Applied Physiology)
- Thermoregulation during rest and exercise in the cold in pre- and early pubescent boys and in young men (Journal of Applied Physiology)