Losing most of your heat through your head is a popular myth. Head heat loss is not the majority of body heat lost. Not even close.

Years of my career in research have been to study how the human body performs in extremes – exercise, injury states and how to prevent them, working and exercising in heat and cold, changes in air and pressure on mountain tops, and the related but different problems in space and underwater. I have lived in laboratories underwater and done experiments aboard aircraft. I have studied combat swimmers and done extreme swims with them for fun. For military research, I put men in vats of freezing water to see how we can keep pilots alive after bail-outs and how to get covert swimmers to their objective and, I found out, an entire separate topic to get them back again. Strong brave men got hazardous duty pay just to have a day with me. My life is scientific research and finding out why things are the way they are and how to make us better at surviving them. After finding out all these interesting things, I found out another thing – people still like myths more than fact. Here are some interesting facts (cool facts on cold):

  • Head heat loss is usually less than one-third to one-fifth of total heat loss. That means it is not the majority, which would be more than 50%. Head heat loss is usually less than 20-30 percent or so of total heat loss.
  • Head heat loss changes with how cold it is. The lower the temperature, the higher percentage head heat loss. Head heat loss is linear with temperature. At 0 degrees Centigrade, up to about 30 to 35% of heat could be lost through your head at rest.
  • Head heat loss changes with how much you exercise. When exercising at about a work rate of 50% of aerobic capacity, head heat loss falls to less than half of heat loss at rest.
  • Head heat loss changes if you are in water compared to air.
  • The heat you lose from your head is small compared to the rest of your body. Some people have bigger heads than others in proportion to their stature, so maybe they can lose a percentage more heat. To reduce heat loss, wear a hat.