From the (fantastic) book What Doesn’t Kill Us by Scott Carney:
Every human alive today lives in a cocoon of consistency: an eternal summer. We’re overlit, overfed, and overstimulated, and in terms of how long we’ve been on Earth, that’s all new.
Humans have evolved with an innate ability to resist the elements. Our remote ancestors marched across endless expanses of frosty mountains and navigated parched deserts long before they invented the most basic footwear or animal-skin coats. While technology has made us more comfortable, the underlying biology is still there. The key to unlocking our lost potential lies in re-creating the sorts of harsh experiences our ancestors would have faced.
If you’ve been wrapped in a thermogenic cocoon for your whole life, then your nervous system is aching for input.
Exposure to cold helps reconfigure the cardiovascular system and combat autoimmune malfunctions.