I remember when I would have a fever and would not tolerate even lukewarm water, so I assume that tolerance to cold is, ceteris paribus, a suggestion that I am okay (of course, this is but a single point of data). When I first bathed in cold water, I had a shocking initial experience: as soon as the water touched the most sensitive parts of the body (scalp, chest, and back) I instinctively took a deep breath and momentarily felt like time had paused at the point where innumerable tiny crystals were piercing through my skin. What cold showers and this latest experiment of mine have in common is the creation of controlled discomfort.