#cold-exposure

#cold-exposure

You can lose 4045% of body heat from an unprotected head. That's the advice in a 1970s US Army Survival Manual, which is probably where this myth originated, says John Tregoning, a professor of vaccine immunology at Imperial College London. The reality is that there is nothing special about your head. When you go out in the cold, you lose more body heat from any area you leave exposed than from those parts protected by clothing.

I don't look at it as too far different from any other kind of extreme challenge where conventional wisdom will tell you that this doesn't make a whole lot of sense," Siddiqi said. "The process of actually achieving it I think can have significant physical and mental impact and can reshape your view of yourself or your view of your capabilities or your understanding of your body and its limitations," he added.