The Body Heat Myth Your Parents Got Wrong

You Should Know: Parents have long passed down the common wisdom that you lose most of your body heat through your head. But surprisingly, the numbers don’t quite add up. The myth likely originated from a 1970s U.S. Army survival manual that claimed you could lose 40 to 45% of your body heat through an uncovered head.

Going Deeper: The reality is much less dramatic. Research shows that you lose heat from your head roughly in proportion to its size, which is about 10% of your body’s total surface area. There’s nothing uniquely heat-shedding about your scalp. If you were wearing a snowsuit without a hat, you’d lose heat quickly from your head. But if you hit the Arctic in a swimsuit, you’d lose far more heat from your legs simply because they have more surface area.

Takeaway: Your head has slightly less natural insulation than other body parts because there’s less fat up there. Blood vessels near the scalp surface can also make your head somewhat vulnerable to cold. But any exposed skin loses heat in cold weather.

Bottom Line: Wear a hat when it’s freezing, not because your head is a heat-loss superhighway, but because exposed skin gets cold. Cover your face too if you can.