I was reading a book recently that recommended infants wear a hat almost constantly in their first year, because “most of your body heat is lost through the head.” I was finding myself getting cross with this advice, because for a few years now I’ve known that statement\u00a0 simply isn’t true. But of course for many years before that, I also confidently stated that “most of the body’s heat is lost through the head.”<\/p>\n
So naturally I googled it, and found out that this misconception came about through a rather unscientific study:<\/p>\n
“…hat-wearing advice [is traced] back to a US army survival manual from 1970 which strongly recommended covering the head when it is cold, since “40 to 45 percent of body heat” is lost from the head.<\/p>\n
Rachel Vreeman and Aaron Carroll, at the centre for health policy at Indiana University in Indianapolis, rubbish the claim in the British Medical Journal<\/span><\/a> this week. If this were true, they say, humans would be just as cold if they went without a hat as if they went without trousers. “Patently, this is just not the case,” they write.<\/p>\n The myth is thought to have arisen through a flawed interpretation of a vaguely scientific experiment by the US military in the 1950s. In those studies, volunteers were dressed in Arctic survival suits and exposed to bitterly cold conditions. Because it was the only part of their bodies left uncovered, most of their heat was lost through their heads.<\/p>\n The face, head and chest are more sensitive to changes in temperature than the rest of the body, making it feel as if covering them up does more to prevent heat loss. In fact, covering one part of the body has as much effect as covering any other. If the experiment had been performed with people wearing only swimming trunks, they would have lost no more than 10% of their body heat through their heads, the scientists add.”<\/p>\n