Myth

Humans lose most of their body heat through their heads.

Do You Lose Most of Your Body Heat Through Your Head?

Body heat is lost through whatever part of the body is uncovered. We lose about the same amount of heat per square inch of exposed skin anywhere on the body. That said, we certainly feel cold more where blood vessels are densely packed (like the head and chest), and less where they aren’t like the legs.

Is Most of Body Heat Lost From the Head? Nope, it’s about how much skin you expose, not where that skin is. Considering many of us have hair on our heads, one could argue the head needs extra covering less than other parts of the body. Also, it’s culturally preferred over going without pants in many regions of the world.

Where Did the Heat Loss Myth Come From?

Your mother may have said that you lose 40% to 80% of your body heat through your head. She was wrong. She might have believed the US Army Field Manual when she read that almost half of your body heat is lost through your head.[6] It seems logical that this would be true, but it isn’t. The idea behind the myth was probably based on research in arctic survival using subjects in cold weather gear, but no hats. Not surprisingly, they lost most of their body heat through their uncovered heads.[2]

Body Heat

How Much Heat Is Lost Through your Head?

According to a 2008 report in the British Medical Journal, we lose 7 percent to 10 percent of our body heat through our heads if our heads are uncovered while the rest of the body is covered.[1] If we wore shorts but covered the rest of our bodies, we’d lose most of our body heat through our exposed legs.

Is Covering The Head Important?

Covering our heads is important, and the lower the temperatures that we are exposed to, the more important it is. When we are cold, our bodies respond in two ways. First we shiver and generate heat by moving. If this does not work well enough, blood flow to the extremities is reduced; we use our blood to keep our core and vital organs warm, and sacrifice fingers, toes, ears, and noses to frostbite. Naturally we’d like everyone to avoid sacrificing body parts. Adults may be able to survive without hats unless it is freezing, but babies are different. Their heads are proportionally larger in relation to their bodies than is the case with adults. Covering a baby’s head can be critical to their well being, especially in newborns. When an adult does not wear a hat, they may feel as though they are losing a lot of body heat through their heads. The blood vessels are closer to the surface in the scalp, wrists, and ankles. You feel cold more in these areas and feel warmer when they are covered.[7]

Why Did We Believe This Myth to be True?

Our heads and upper chest are five times more sensitive to temperature changes than other areas of our bodies.[4] These areas are densely packed with blood vessels and nerves. There is far less subcutaneous fat on the head to act as an insulator than in the rest of the body.[1] The head and chest are sensitive areas, so we may feel cold or warmth more in our heads than our legs, but that does not mean that we lose even twice as much heat through the surface of the head than the surface of the leg. We lose about the same amount of heat per square inch of exposed skin anywhere on the body.



Conclusion

It’s a myth that we lose most of our body heat through our heads. We lose body heat through whatever surface is uncovered fairly equally.


References

  1. Head cover in the cold” Published 18 December 2008 Bmj.com

  2. Do We Really Lose Half our Body Heat From our Heads?
    ” Livescience.com
  3. The Claim: You Lose Most of Your Body Heat Through Your Head” NYtimes.com
  4. Do We Really Lose Most of Our Heat Through Our Heads?” Webmd.com
  5. Lloyd Evan L “Hypothermia and Cold Stress” Croom Helm, Kent. 1986
  6.  Peter T. Underwood “U.S. Army Survival Manual” Department of the Army. Skyhorse Publishing, Inc. Dec 13, 2013
  7. Do you lose the most heat From your head?” BBC.com


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