Is most of my body heat lost through my head?

Moms for years have urged children to wear hats in the winter to keep warm, and even a U.S. Army manual emphasized that a hat is essential in cold weather. Yet hypothermia experts say estimates of how much body heat is lost from a bare head are off the mark. In general, we lose only about 10 percent of our body heat through our heads; body heat is lost through any body part that is uncovered, including the hands and feet. It might feel like more heat is lost through the head because the head and face are more sensitive to temperature changes. Bundling up is still a good idea, however, because hats and gloves do protect against overall heat loss.

It may be the reason your mother always made you wear a hat when you went outside in the winter, but this is an urban legend. It probably has its origins based on Arctic experiments conducted by the United States military in the 1950s. Volunteers in those trials donned survival suits (no hats) and were tested for their tolerance for exposure to extremely cold temperatures. Today's researchers assert that the only reason the volunteers in those experiment lost so much heat through their heads is that their heads were their only body part exposed in these experiments. They also assert that, although our head and chest are particularly sensitive to temperature changes, no single body part loses more heat than others. New studies find only about 10% of the body's heat escapes from an uncovered head, much lower than the 40% to 80% claimed by the army in their original survival manual.