Sunday, December 21, 2008
Since most of the country is experiencing some rather nasty cold weather, here is a report from the British Medical Journal to let you know that all those calls for you to wear a hat might have been less than helpful. Here is a brief excerpt from the Guardian. Ian Sample writes,
When it comes to wrapping up on a cold winter's day, a cosy hat is obligatory. After all, most of our body heat is lost through our heads – or so we are led to believe. Closer inspection of heat loss in the hatless, however, reveals the claim to be nonsense, say scientists who have dispelled this and five other modern myths.
They traced the origins of the hat-wearing advice 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.
Rachel Vreeman and Aaron Carroll, at the centre for health policy at Indiana University in Indianapolis, rubbish the claim in the British Medical Journal 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.
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.
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. . . .
The report also debunks other seasonal myths about children, sugar and hyperactivity (not sharing this article with my "just one more cookie Mom" son) and some rather bad news for those interested in hangover remedies as well. The article is an interesting read.