Cold Exposure
Mood and inflammation signal; mechanism partially understood; popular claims outrun the science.
Proposed mechanism
Cold activates the sympathetic nervous system, increases norepinephrine, and may activate brown adipose tissue. Cold water immersion triggers vasoconstriction followed by reactive hyperemia.
Strongest evidence
Small RCTs show mood improvements and reduced inflammation markers. Wim Hof method studies show some immune modulation. Cardiovascular adaptation data is emerging.
What's contested or hyped
Metabolic boost claims, testosterone increases, and 'ice bath every day' protocols lack consistent human trial support. Risk for cardiovascular events in susceptible individuals.
Biome describes modalities; it does not recommend protocols, products, or providers. Consult qualified clinicians for medical decisions.