The Science and Protocols of Deliberate Cold and Heat Exposure for Metabolism, Mood, and Health with Dr. Susanna Soberg

This episode features Dr. Susanna Soberg, a leading expert on deliberate cold and heat exposure, discussing their profound impact on human physiology. Her research, including a seminal study published in *Cell Reports Medicine*, established minimum thresholds and actionable protocols for increasing brown fat thermogenesis and improving overall health. The discussion delves into how these exposures activate the sympathetic nervous system and increase catecholamines like dopamine, epinephrine, and norepinephrine, which are crucial for mood, metabolism, and alertness.

Dr. Soberg elucidates the physiological cascade initiated by cold exposure, explaining that cold receptors in the skin rapidly signal the hypothalamus, directly activate brown fat, and trigger shivering in muscles, all contributing to thermogenesis. A key distinction is made between various cold exposure methods—cold showers, partial immersion, and full immersion—with full immersion being the most potent due to comprehensive cold receptor activation. The concept of "cold shock" is introduced as a necessary discomfort for initiating beneficial responses, emphasizing that adaptation reduces the hyperventilating response over time, building resilience.

Practical insights include the importance of embracing discomfort and shivering, which is described as a "healthy stress" (hormesis) that trains cells and improves insulin sensitivity. The phenomenon of "afterdrop" is explained, where core body temperature continues to decrease post-exposure due to peripheral vasodilation, often leading to delayed shivering. This understanding underpins the "Soberg Principle," advocating for ending on cold to maximize the body's natural warming response rather than immediately seeking external heat.

The broader implications extend beyond metabolism to mental and physical performance, highlighting the role of cold and heat in enhancing mental balance through neurotransmitter modulation. The episode underscores the accessibility of these protocols, from simple cold showers to specialized cold plunges, as tools for everyday life. Dr. Soberg's work bridges a gap in scientific understanding, providing evidence-based guidance for safely integrating these powerful stressors into a routine for long-term health benefits.

Her research has focused on how deliberate cold exposure and deliberate heat exposure can be used to enhance human metabolism.

She is the first author of a seminal study which discovered the minimum thresholds for deliberate heat and deliberate cold exposure for increasing Brown fat thermogenesis which is essentially a mode of increasing heat production and Metabolism in the body and for establishing actionable protocols that can be used outside of the laboratory to improve metabolism and human health.

The so-call catacol amines which strongly impact mood and Metabolism.

You should get uncomfortable cold so as long as you get uncomfortable cold it's cold enough and you get this what we call the cold shock.

This is like building up your resilience building building up your adaptation is going to make this shock like subside a bit so it's it's always harder in the beginning but you should do hard things right.

The more you can say you cover your body in the cold which you would do in cold water because there of course cover totally and then and the molecules are closer to your skin you will have a more potent um activation of all your cat receptors in the skin.

Shivering is is good because that increases your metabolism and that's going to burn some calories in your body.

What's called the after drop is when your core temperature uh decreases even after you get out of the cold water and it always does that.