In this episode of the Huberman Lab podcast, Dr. Andrew Huberman is joined by Dr. Susanna Søberg, a leading expert on deliberate cold and heat exposure protocols. They delve into the science behind cold exposure and sauna therapy, discussing the impact on human physiology and the numerous health benefits associated with these practices.
Deliberate cold exposure activates the sympathetic nervous system and neurotransmitters like dopamine, epinephrine, and norepinephrine. It can be achieved through cold water immersion, exposure to cold wind, or cold showers. Cold exposure should feel uncomfortable to be effective, and spending more time in slightly uncomfortable cold water can provide similar benefits to short periods of very uncomfortable cold water. The “cold shock” is the activation of the sympathetic nervous system and catecholamines, and can be gauged by difficulty controlling breathing. Cold exposure can activate the sympathetic nervous system and cause hyperventilation, but adaptation can reduce this response. It is important to embrace the discomfort of the cold as it builds resilience and adaptation. Different cold exposures have different impacts on the body and cold receptors in the skin. Cold water immersion activates cold receptors in the skin, leading to a potent activation of the autonomous nervous system. Going out in cold wind in a t-shirt activates the sympathetic nervous system, increasing norepinephrine and activating brown fat, a healthy fat tissue that increases metabolism. Brown fat is the first responder in the body to keep our temperature up, and muscles are the second tissue that start to shiver to increase body temperature. Cold showers immediately activate brown fat, which could increase metabolism, but more studies are needed to fully understand their impact on metabolism and mental balance.
Deliberate cold exposure leads to long-lasting increases in catecholamines, dopamine, norepinephrine, and epinephrine. It also leads to metabolic changes such as activation of brown fat, more efficient mitochondria, and better capillaries in the skin. Winter swimming has been shown to lower blood pressure, heart rate, and improve insulin sensitivity in middle-aged men and women. Brown fat can decrease unhealthy white fat by taking up glucose and fatty acids from the bloodstream. Activating brown fat through temperature changes can lead to a higher metabolism and better insulin sensitivity. Brown fat is located centrally around the central nervous system, with the biggest depot under the clavicular bones and very close to the skin surface. Cold adaptation can be achieved by wearing a t-shirt in a cold environment for a few days, which can activate brown fat and lead to increased comfort in cold environments and potentially weight loss. Adjusting feeding and seasonal changes in light, temperature, food, and movement can have a powerful effect on the body’s thermal regulation.
Deliberate cold exposure and sauna therapy can have additional benefits beyond regulating blood sugar, brown fat, and metabolism. They can lower inflammation in the body, prevent lifestyle diseases, and improve mental health. Cold exposure should end on cold to force the body to heat up by itself, which activates brown fat and muscles. Regular cold exposure can make the body more efficient at generating heat. Sauna therapy, when done for 57 minutes in total per week, divided into three 20-minute sessions, can lower the risk of cardiovascular disease. The hermetic stress or healthy stress achieved through deliberate cold exposure and sauna can strengthen cells in the body, increase heat shock proteins and cold shock proteins, and improve overall health. Cold exposure and sauna therapy should be approached with caution, and protocols should be tailored to individual needs and comfort levels.
Deliberate cold exposure and sauna therapy have numerous health benefits, including improved metabolism, activation of brown fat, and regulation of blood sugar. These practices are becoming more mainstream, thanks to the research and expertise of scientists like Dr. Susanna Søberg. By embracing the discomfort of the cold and incorporating deliberate cold exposure into our routines, we can enhance our physical and mental well-being.