Wim Hof is probably the reason that cold immersion therapy got popular. He did a record time of staying in ice cold tank and climbed the Everest in his shorts. It was all for his breathing technique, which, for the purpose of making it easier to understand this essay, is explained simply as (1) 20-40 deep belly breathes via nose or mouth followed by (2) upon exhale, hold your breath as long as you can i.e 30s and breath in for 15s (3) repeat the cycle. Several benefits of this method includes hyperventilation triggers your autoimmune system to pump adrenalines aka epinephrines which is basically the “gasoline” powering your body through dangerous situations. Furthermore, as observed in Wim, practicing this technique also decrease your immune responses in several autoimmune diseases. In this specific case of ice immersion, our natural autoimmune responses usually include organ shutting down and vascoconstriction (blood vessels shrinking), fight or flight responses, shivering. With Wim Hof’s technique training, people have proven to be able to run/go hiking in the snow in shorts. The technique is not widely accepted by science communities.