Nearly naked and immersed in ice cubes up to the neck, two Chinese men recently duked it out in a cold-endurance contest for two hours. My low-temperature-loving grandfather, a member of the polar bear club, used to plunge regularly into freezing Finnish waters as a form of leisure. No matter the weather, my son, too, seems happy to storm the playground, sweating under his Siberian hat, while my own toes have been frozen for months. Why are some people so much heartier in the cold?
http://www.slate.com/id/2282969/