The Iceman Cometh: Can you train your body to withstand extreme cold?

Dutchman Wim Hof, better known as "Iceman" for his ability to withstand seemingly impossible levels of cold, speaks at a hotel in Kathmandu, 28 May 2007. 'Iceman', who failed in his attempt to conquer Mount Everest wearing just shorts vowed to have another half-naked crack at the world's highest peak next year. Hof said that next year he would try Everest again, and then with a paraglider and two French people they would fly down.

Wim Hof is a Dutch man who claims he has trained his body to withstand extreme cold. He has hiked two-thirds up Everest in only shorts, run marathons barefoot in the Arctic Circle and submerged himself below ice for 72 minutes.

Wim Hof is a Dutch extremeophile who claims he can consciously train his body to withstand cold that would kill other men.

He has hiked two-thirds up Everest in only shorts, run marathons barefoot in the Arctic Circle and submerged himself below ice for 72 minutes. Scientific study of Hof has borne out his claims. It is thought he has built up so-called "brown fat," a type of fat that can be burnt easily by the body to generate heat.

All humans have brown fat when they are babies, which allows them to live without getting hypothermia, but most people lose their brown fat cells unless they are exposed to extreme cold temperatures.

Hof is the subject of a profile by Scott Carney, in this month's Playboy magazine.

Carney visited Hof's training school in the Polish wilderness where he learned to lie in snow for extended periods and eventually climbed a mountain bare-chested in below freezing weather.