Archive for October 27th, 2006

Frozen Mythbusters, Myth #2

October 27, 2006

Frozen Mythbusters: Myth #2 of 13.
There are a variety of myths regarding human response to cold exposure.  These myths are explained and debunked by Dr. Murray Hamlet, DMV, Dr. Gordon Giesbrecht, PHD, and Frank Hubbell, DO.  After posting the thirteen myths, a complete article  from the Wilderness Medicine Newsletter will be loaded for anyone interested in all the chilly little details.
 

Myth #2
           If your feet are cold, cover your head because you can lose up to 75% of your body heat through your head alone.
           The problem is that the head is only about 10% of the body surface area. Thus, the head would have to lose about 40 times as much heat per square inch or centimeter compared to the rest of the body.
           Gordon had heard this statement one too many times and finally decided to see if this was indeed true. So he took several test subjects, all volunteers, of course, (you have to wonder what problem they caused at the university), wired them to monitor their core temperatures, and discovered that we do indeed lose heat through any exposed part of the body and the amount of heat we lose depends on the amount of exposed surface area. The rate of heat loss is relatively the same for any exposed part of the body, not simply the head. You do not lose heat significantly faster through the scalp than any other portion of the body with the same surface area. 
             It is still a good idea to put on a hat (a hood really – what insulation does a baseball hat have?) if your feet are cold. But what is busted is that there is nothing peculiar or unique about the head. The idea that we lose heat faster through out scalp, because of the constant blood supply to the brain, is simply a myth. (One that I personally have believed for many years.)

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