Either the researchers or, far more likely, the journos, have displayed a degree of ignorance here which can be fatal. I despaired a long time ago of journos, but I am beginning to despair over the current crop of young 'researchers' too - especially when they step outside their very narrow range of knowledge.
> because around 40-45% of body heat is lost through the head.
Make that 'up to 40-45% of body heat CAN be lost through the head' and you would be right. Marvellous how changing one word can alter the whole meaning.
> A recent study, however, showed there is nothing special about heat loss from the head
> - any uncovered part of the body would lose heat.
True in itself - of course. BUT...
When your arms and legs get cold the blood flow to them reduces in order to save heat for the core and head. OK, you end up with frostbite of the extremities, but you live.
When your head gets cold, by just a degree or two, you first go stupid and then you die. No frostbite, just shutdown. There is a difference!
> Scrutiny of the literature shows this myth probably originated with an old military study
I dare say the information comes from an old military study, but I wouldn't call it a myth. It is very real.
> If the experiment had been done with the participants wearing only swimsuits they would
> not have lost more than 10% of their body heat through their heads, the researchers said.
Ahh... yeah, right. So you stand there in the middle of the snow field in a swim suit and you get cold all over. Why am I not surprised?
The root of the story lies in the fact that your body will, come what may, keep shunting more and more hot blood to your head to keep it at 98 F whether or not your extremities are freezing (literally). So you may feel OK because your head is warm enough - while you slowly get frostbite in your hands and feet.