Hormesis is a compensatory defense response to a stressor that conditions the body against future stressors. Cold exposure, a powerful hormetic stressor, activates the body's cold shock response, the goals of which are simple: to reduce heat loss and increase heat production. It does this by increasing brown fat and enhancing mitochondrial biogenesis – obvious ways to help the body stay warm. But the downstream effects of the response include reduced inflammation, improved mood, and – at least in endurance athletes – better performance.

In this episode, part two of a two-part series, I describe the many health benefits of cold exposure, the mechanisms that drive them, and some of the safety concerns.