Cold Therapy: The Secret Weapon to REPROGRAM Your Body & Mind | Dr. Susanna Søberg

Episode Summary

Executive Summary: Lewis Howes interviews metabolism researcher Susanna Søberg about how deliberate cold and heat exposure can improve health. She explains brown fat vs. white fat, how cold plunges and saunas affect metabolism, glucose control, blood pressure, mood, and pain tolerance, and why the practice should be individualized and done safely.

Main Topics: Brown fat and metabolic health (Priority: 5/5): Søberg explains that brown fat is a healthy tissue activated by cold, helping burn glucose and fat to generate heat, while white fat stores energy and contributes to obesity and disease risk. Cold exposure and winter swimming (Priority: 5/5): The conversation centers on deliberate cold exposure, especially winter swimming and ice baths, as a way to activate thermogenesis, improve glucose balance, and increase cold adaptation over time. Heat therapy and sauna benefits (Priority: 4/5): They discuss Finnish and infrared saunas, their different physiological effects, and research showing regular sauna use may reduce cardiovascular risk and support vascular and skin health. Brain-body connection and mood (Priority: 5/5): Søberg says she only fully understood the science after practicing winter swimming herself, experiencing changes in gratitude, calm, and mental state that align with neurotransmitter shifts. Safety, dosage, and individualization (Priority: 5/5): She emphasizes that cold/heat exposure must be safe, avoid breath-holding or overexposure, and be tailored to health status, especially for people with heart conditions or high blood pressure. Breathing and nervous system regulation (Priority: 4/5): Breath control is presented as the main tool for managing the cold shock response and for calming the nervous system in stressful situations through slow nasal or box breathing.

Key Arguments: Brown fat is a metabolically active tissue that can help burn visceral white fat and improve glucose metabolism when stimulated by cold exposure. Deliberate cold exposure increases thermogenesis, norepinephrine, dopamine, and other neurotransmitters, which can improve mood, motivation, and resilience. Regular winter swimmers showed better glucose control, lower insulin, lower blood pressure, and higher brown fat activation than controls. Sauna use appears to provide cardiovascular and vascular benefits; the best results come from moderate, consistent exposure rather than overdoing it. The main tool for staying safe and calm in cold water is breath regulation; hyperventilation and head dunking increase risk. Cold and heat exposure should be treated like beneficial stressors: enough to adapt the body, but not so much that they become harmful.

Data Points: Research start year: 2016 - Søberg says she began her metabolism/brown fat research in 2016. Cold-water swimming dose: 11 minutes per week - Observed in winter swimmers, divided across 2-3 days and multiple short dips. Per-dip duration: 1-2 minutes - Approximate length of each cold-water immersion session in the study. Study duration: 5-7 months - The winter-swimming intervention followed participants across a season. Blood pressure reduction: Lower baseline blood pressure - Winter swimmers showed lower blood pressure and heart rate at baseline than controls. Glucose tolerance: Better/faster glucose metabolism - Winter swimmers processed a sugar drink more efficiently in testing. Insulin levels: Lower insulin levels - Associated with improved insulin sensitivity and glucose handling. Cold-water temperature definition: 15°C and under - Søberg defines cold water as 15 degrees Celsius or lower. Sauna benefit threshold: 27% lower cardiovascular disease risk - Finnish sauna cohort: 2-3 sauna sessions per week vs. once weekly. Sauna benefit threshold: 46% lower cardiovascular disease risk - Finnish sauna cohort: daily sauna use vs. once weekly. Sauna session window: Around 30 minutes max - Benefits plateau and may reverse if sessions are extended beyond this. Study-derived heat dose: 57 minutes of heat per week - Suggested total weekly sauna exposure in Søberg’s study, divided over 2-3 days. Sauna session range: 10-20 minutes - Optimal window suggested by the sauna cohort data. Cold effect on neurotransmitters: Dopamine up to 5x higher - Søberg cites increases in dopamine after cold-water immersion. Cold effect on neurotransmitters: 2.5x to 5x higher - Range given for dopamine increases from cold exposure. Cold exposure and heat loss: 36% extra heat loss - Head dunking increases heat loss compared with neck-level immersion.

Pivotal Quotes: "it didn't really match what I read. So there was something missing there. And only when I started doing this myself, I understood, aha, it's the connection between what is going on in your physiology and your brain." — Susanna Søberg: She explains the moment she connected the research to the lived experience of winter swimming. "The white fat is storing your fat in the body, and the brown fat is using the fat in the body." — Susanna Søberg: A concise explanation of the key biological distinction at the center of the interview. "if you end on the cold, you activate your metabolism once again" — Susanna Søberg: Her recommendation for alternating sauna and cold exposure in the same session.

Implications: For listeners, the episode frames cold/heat therapy as a practical, evidence-based stressor that may improve metabolic health, mood, and resilience if used safely. For the wellness industry, it underscores the need for better education, dosing guidance, and individualized protocols.