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This myth probably came from experiments in the 1950s, when military researchers exposed subjects to frigid temperatures. The final results concluded that 40-45% of all body heat was lost through the head due to the nature of the experiment leaving the participants’ heads exposed to the cold air.
In reality, the head only represents about 10% of the body’s total surface area. Therefore making 40-45% body heat loss unlikely. Per an article by WebMD, according to Richard Ingebretsen, MD, Ph.D., an adjunct instructor in the department of internal medicine at the University of Utah School of Medicine, “The real reason we lose heat through our head is that most of the time when we’re outside in the cold, we’re clothed…If you don’t have a hat on, you lose heat through your head, just as you would lose heat through your legs if you were wearing shorts.”
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