Dr. Susanna Søberg: How to Use Cold & Heat Exposure to Improve Your Health
Main Takeaways
Focus on the level of discomfort rather than a specific temperature when experiencing cold exposure, aiming for uncomfortably cold but safe conditions.
Train and adapt to cold exposure gradually, as shock can subside with time and practice.
People vary in their ability to tolerate and embrace the cold, so resisting it may make it feel worse for you.
The more of your body you expose to cold water, the stronger the activation of cold receptors on your skin.
Exposure to cold air can increase norepinephrine and activate brown fat, leading to an increase in metabolism.
Brown fat and muscles (shivering) are the two tissues that increase thermogenesis in response to cold.
The dive reflex, a survival mechanism, slows down the body's oxygen response and activates the sympathetic nervous system after 1-2 minutes of cold exposure.
Shivering increases metabolism and can be seen as training your cells to healthy stressors.
After leaving the cold, blood vessels initially constrict to keep vital organs warm, but they open up again.
Brown fat, located around the organs, is essential for temperature regulation and can be activated by cold receptors and noradrenaline.
Brown fat can grow and increase in response to an increase in noradrenaline, which can be promoted through early and lifelong physical activity.
Sleep in a very cold room, dipping a hand in cold water, and exposure to cold air can ease into cold exposure, activating brown fat and improving insulin sensitivity.
Cold exposure can improve insulin sensitivity, glucose clearance, and inflammation biomarkers, potentially impacting disease outcomes.
Ending cold exposure sessions with cold exposure helps maintain the activation of neurotransmitters and thermogenesis for hours afterward, promoting brown fat and muscle activity.
