The Head and Heat Loss

There is some truth to the saying that most of your body heat is lost through your head, and there are a couple of reasons for this. First and foremost, the biggest factors in how much heat is lost from a given location are conductivity and surface area. Skin is skin regardless of where it is on the body. In some places it is thicker, in others it is covered by more hair, but you get right down to it and your skin is actually pretty consistant in just how much heat it looses.

But we are not ready to move to surface area quite yet. The insulation value of skin is pretty consistant, but our ancestors figured that out thousands of years ago. This is why we wear coats. Now it is not just the skin that we would have to account for, but any clothing worn on top of it as well. Which is where surface area comes into it. The head does not have the largest surface area for skin on the body, but it does have the largest exposed surface area. Thus, for most of us the head is the biggest source of heat loss, just because it is one of the last places to be protected.

But there is a second point to consider above and beyond the exposure of your noggin, though this one is just as conditional. When you are warm your heat loss is about equal everywhere (leaving aside the insulation mentioned above.) As you begin to get cold though, your body progressively reduces blood flow to your extremeties. This goes from the fingers and toes, through hands and feet, arms and legs, and into the torso until the only places getting blood are the heart, lungs, and brain. But the heart and lungs are buried in the torso while the brain is literally out on a limb. Leaving us, again, with the head being the point of least protection and highest heat loss.

However, leaving these 2 points aside, inch for inch the base heat loss from your head is no different than any other part of the body.