Huberman Lab Essentials revisits Andrew Huberman's conversation with Dr. Susanna Søberg, a researcher studying cold and heat exposure, brown fat, and metabolic health.
Cold should feel uncomfortable, but extreme temperatures aren't required. Her winter swimmer study found about 11 minutes of cold water and 57 minutes of sauna per week, split over 2-3 visits, linked to better insulin sensitivity and faster glucose clearance with less insulin. Ending on cold forces the body to rewarm itself, keeping brown fat and muscle working for hours. Sleeping at 19°C for a month increased brown fat and insulin sensitivity, while 24°C and 27°C reversed it. Alternating warm and cold matters more than exact temperature, and Søberg links lower inflammation to reduced lifestyle-disease risk.