Summary
Shawn Stevenson interviews Dr. Susanna Soberg, one of the world's leading researchers on cold immersion therapy and brown adipose tissue. The conversation covers the science of brown fat, how it differs from white fat, and why cold exposure is one of the most effective ways to activate it for metabolic benefits. Dr. Soberg explains the mechanisms behind cold shock proteins, their role in cellular repair, and how they differ from heat shock proteins. The episode dives deep into the practical applications of cold therapy, including its effects on insulin sensitivity, inflammation reduction, immune system modulation, and mental health. Dr. Soberg shares her research findings on how regular cold immersion lowers blood pressure, improves stress resilience, and activates both the sympathetic and parasympathetic nervous systems. She explains the concept of hormetic stress and how short-term cold exposure builds long-term resilience. Key practical takeaways include the recommendation to always end contrast therapy sessions on cold rather than hot, to use nasal breathing during cold immersion to shift from sympathetic to parasympathetic activation, and that the body adapts quickly to cold exposure. Dr. Soberg also discusses the important role of dopamine released during cold exposure, which mirrors the effects of exercise on the brain's reward system.
Key Points
- Brown adipose tissue burns calories rather than storing them, and gets its brown color from dense mitochondria
- Cold shock proteins are activated only in the cold and help repair damaged proteins as we age
- Cold exposure increases leucocytes and monocytes in new practitioners, while adapted swimmers show lower baseline levels indicating reduced inflammation
- Always end contrast therapy sessions on cold to force the body to heat itself up, increasing metabolism
- Nasal breathing during cold immersion helps shift from sympathetic fight-or-flight to parasympathetic calm
- Cold exposure triggers dopamine release identical to exercise-induced dopamine, increasing stress resilience and pleasure sensitivity
- The body adapts to cold exposure quickly, with recovery time shortening as one becomes more practiced
- Coffee consumption can nudge beige fat cells toward becoming metabolically active brown fat
Key Moments
Brown fat burns calories instead of storing them
Shawn Stevenson introduces brown adipose tissue as a special fat that burns fat for fuel rather than storing it, and how cold exposure is the key to activating it.
"There's a special kind of fat that has been recently discovered called brown fat or brown adipose tissue. And this fat, funny enough, it actually burns fat for fuel rather than being very, very good at storing it."
Cold shock proteins repair damaged cells and slow aging
Dr. Soberg explains how cold shock proteins are uniquely activated by cold exposure and play a critical role in repairing damaged proteins that accumulate with aging, complementing the effects of heat shock proteins.
"there are cold shock proteins which are different and activated only in the cold. They have overlapping efficiency to activate or making the cells stronger and repair the cells, repair the proteins which get damaged with years."
Cold exposure improves insulin sensitivity through brown fat activation
Dr. Soberg details how cold immersion lowers inflammation and increases insulin sensitivity by activating brown fat, which helps clear glucose from the bloodstream faster and reduces risk of type 2 diabetes.
"increasing your insulin sensitivity will make your cells in your body more sensitive to insulin, of course, and then you will get faster rid of the glucose that is floating around in your bloodstream"
Dopamine from cold exposure mirrors exercise benefits
Cold immersion triggers dopamine release that is the same as exercise-induced dopamine, sensitizing the brain to pleasure and increasing overall stress resilience.
"It is the same as what you get from exercise."
Always end contrast therapy on cold to boost metabolism
Dr. Soberg recommends always ending contrast therapy sessions with cold rather than heat, as this forces the body to generate its own heat through brown fat activation, thereby increasing metabolism.
"if you do that by time when you have adapted a bit, you quicker increase your heat in your body by activating the brown fat when you end on the cold. So this is going to force your body to heat up. It's going to increase your metabolism. So that's why I always say end on the cold."
Use nasal breathing to shift from fight-or-flight in cold water
Dr. Soberg explains how nasal breathing during cold immersion activates the parasympathetic nervous system, helping practitioners stay in the water longer and adapt more quickly to the cold stress.
"you can use nasal breathing and try to do that at least by lowering your breath in that way and switching from the sympathetic activation, the fight and flight, to the parasympathetic activation. And when you are able to do that, then you will be able to stay in"
