Re: How much heat is loss thru head?

Annette,
Iīve always wondered that myself. Generally, it was in the context of wanting to tell my mom that I didn't need to put a hat on.... I've sinced wisened.

As far as I've been able to find (I feel your pain - itīs been pretty to hard to find!), about 30% of one's body heat can be lost through the head. About 13-16% of the body's blood volume is in the head at any given time, but it is a very exposed structure, allowing it to lose heat pretty quickly. Incidentally, the neck is also a place of easy heat loss, so keep that scarf on as well!

Though it is important to prevent general heat loss, the most important reason to keep a hat on (and your body temperature up) is that the brain requires the most blood, and needs that blood to be the right temperature. Your brain controls everything else in your body (your ability to think and act, as well as the ability for your body to maintain a particular temperature). Symptoms of hypothermia include confusion, weakness, and slowed breathing. It's really critical to make sure your brain is getting all it needs, or else your body will shut down!

A definition of hypothermia (with some tips and things to look for) can be found at: http://my.webmd.com/content/asset/adam_injury_hypothermia

The Merck manual's guide on cold weather ailments (frostbite, etc) is here: http://www.merck.com/pubs/mmanual/section20/chapter280/280a.htm
(this is where I found that 30% number)

Hope that helps!

Alex G
cgoddard@fas.harvard.edu