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

Episode 124 May 15, 2023 2h 26m 20 insights
In this episode, my guest is Susanna Søberg, PhD. She earned her doctoral degree at the University of Copenhagen in Denmark, researching the effects of deliberate cold and deliberate heat exposure on metabolism and other aspects of human physiology. We discuss how cold or sauna can improve metabolism, cardiovascular and brain health, balance hormones, and decrease inflammation. Dr. Søberg discusses how deliberate cold protocols can improve glucose metabolism and insulin sensitivity and trigger release of neurotransmitters like dopamine and norepinephrine which enhance energy, mood, and focus. We compare cold showers and cold immersion, traditional and infrared saunas, and other variables. This episode provides actionable tools and answers to common questions about the use of deliberate cold and heat to improve health. For the full show notes, visit hubermanlab.com.
Actionable Insights

1. Minimum Cold Exposure Protocol

Engage in deliberate cold exposure for 1-2 minutes per session, 2-3 times per week, totaling 11 minutes per week. This duration is sufficient to activate brown fat, increase metabolism, and improve insulin sensitivity.

2. Minimum Heat Exposure Protocol

If combining with cold, use sauna for 10-15 minutes per session, 2-3 times per week, totaling 57 minutes per week. This duration is effective for cardiovascular health and cellular repair, and going beyond 30 minutes per session does not yield additional health benefits.

3. The Soberg Principle: End on Cold

Always conclude your cold/heat alternation with cold exposure. This forces your body to heat up by itself, extending metabolic activation, neurotransmitter release, and brown fat efficiency for hours after the session.

4. Embrace Cold Discomfort & Shivering

Actively seek uncomfortable cold that induces a ‘cold shock’ (e.g., initial hyperventilation) and allow yourself to shiver. This ‘healthy stress’ (hormesis) trains cells, boosts metabolism, and enhances insulin sensitivity, leading to long-term health improvements.

5. Vary Temperature Stimuli

Intentionally vary the temperature of your cold exposure or alternate between cold and heat. This continuous challenge keeps your body’s cells robust and adaptive, preventing over-adaptation and maintaining the hormetic stress response.

6. Hydrate with Electrolytes Daily

Dissolve one packet of electrolyte mix (sodium, magnesium, potassium, no sugar) in 16-32 ounces of water first thing in the morning and during physical exercise. This is critical for optimal brain and body function.

7. Utilize NSDR/Yoga Nidra for Energy

Practice Non-Sleep Deep Rest (NSDR) or Yoga Nidra, even for short 10-minute sessions, to significantly restore cognitive and physical energy.

8. Sleep in a Cool Environment

Maintain a room temperature of approximately 19°C (66°F) while sleeping. This activates and helps grow brown fat, which can improve insulin sensitivity and overall metabolism.

9. Wear Fewer Layers for Cold Adaptation

In colder weather, intentionally wear fewer layers of clothing (e.g., a t-shirt) to expose your skin to cold. This activates brown fat and builds resilience to cold, enhancing your body’s natural heating mechanisms.

10. Prioritize Cold Water Immersion

Submerging most of your body in cold water (up to the neck) provides a more potent activation of cold receptors and the nervous system compared to cold air or showers, leading to greater physiological benefits.

11. Time Cold Exposure Flexibly

Perform deliberate cold exposure when it fits your schedule. If done in the evening, monitor its impact on your sleep quality and adjust if necessary, as it activates the sympathetic nervous system.

12. Children’s Cold Exposure Caution

Children require significantly shorter cold exposure durations than adults due to their smaller body mass, which makes them more susceptible to hypothermia.

13. Avoid Head Submersion in Cold Water

Do not dunk your head in very cold water, as it drastically increases heat loss (by 36% from the core) and decreases blood flow to the brain, elevating the risk of hypothermia and the ‘after-drop’ phenomenon.

14. Wear a Beanie in Cold Water

When immersing in cold water up to the neck, wear a beanie to prevent dizziness, brain freeze, and reduce heat loss from the head, allowing for a more comfortable and potentially longer safe exposure.

15. Manage Extremity Pain

If cold exposure causes intense pain in your hands or feet, keep them out of the water or use neoprene booties. This allows you to still gain full-body benefits without the barrier of localized pain.

16. Submerge Fully (Excluding Head)

To minimize discomfort at the water’s surface interface, submerge your entire body (up to the neck) rather than partial immersion.

17. Cold/Heat Lowers Inflammation

Deliberate cold and heat exposure are effective in lowering systemic inflammation, which can help prevent various lifestyle diseases and improve mental health conditions like depression and anxiety.

18. Cold Exposure for Mental Well-being

Cold exposure activates the parasympathetic nervous system and increases neurotransmitters like serotonin, contributing to improved mental balance, positive mood, and anecdotally, reduced social anxiety.

19. Clothing Optional, Benefits Unchanged

Whether you wear a bathing suit or are naked during cold water exposure does not affect the physiological benefits. The choice is personal and cultural.

20. Cold Exposure for Raynaud’s

While not scientifically proven, some individuals with Raynaud’s syndrome report that regular cold and heat exposure helps improve their symptoms, potentially by improving vascular elasticity, but more studies are needed.