AUSTIN (KXAN) – I’m sure you’ve heard it before: you need to wear a hat when it is cold because we lose most of our body heat through our heads. Is this old wives tale true or not?
Short answer: No. However, you may still want to wear a hat. Here’s why:
According to research published in 2008 in the peer reviewed journal The BMJ, between 7% and 10% of total body heat is lost through the head. Researchers determined this by measuring heat loss when subjects were immersed in water. The head makes up about 7% of the body’s surface area, according to the research.
However, there were some challenges to the results of the study.
Most of the reviews of the paper pointed out that the participants were tested without any clothes on.
“Whilst research does show that heat loss from the head in naked individuals is only 7-10% of the total heat loss, I have yet to observe naked smokers outside our pubs this winter, so this percentage loss is unlikely to be applicable,” said microbiologist Richard H. George in his review of the paper.
Another reviewer pointed out the there is less fat over much of the head than there is in other parts of the body. This means you can feel the cold quicker.
Hair also factors in. Older adults and babies may have less hair. However, the length of the hair doesn’t matter, according to this study on hair and temperature published in 2015.
The researchers did state in their paper that the face and head are more sensitive to temperature changes than the rest of the body.
This wasn’t the first time researchers tried to debunk this myth.
In 2006, research was conducted into heat loss from the head when a person was submerged in cold water. In this study, eight males were dunked in cold water wearing wet suits and wearing nothing. They also did the experiment with their heads under and above water.
Shivering was prevented with medication to better judge heat loss.
The study found that “In 17°C water, the head does not contribute relatively more than the rest of the body to surface heat loss.”
According to multiple sources, the legend of losing “40% to 45% percent of body heat” from your head comes from a U.S. Army Field Manual published in the 1950’s. We were unable to track this manual down to confirm this part of the legend.