Originally Posted by
landdnl
Internally, that's exactly correct. But at the bottom of the page there is this:
- Ezra Burgess, Former Nordic Advisor to the Eastern Division National Ski Patrol.
I have been involved in winter camping for over 35 years. The problem here is that the original statistic is not being stated properly. The original statistic made many years ago was that 50% to 70% of body heat is lost thru the head, neck and shoulder areas of the body. The solution to prevent this was and is to put on a good hat, close up your coat and/or wear a scarf. The heat-loss doesn’t come from the head only; but from the overall collection of heated air trapped in the clothing layers rising from the “chimney effect” caused by an open neck,head and shoulder area allowing all this heated air to escape thus chilling the body. Don’t forget, however, that when engaging in strenuous activities the body will produce greater amounts of heat, requiring you to open these areas for proper ventilation and then re-closing them when activity ceases.
Exactly, what escapes from a "chimney effect," would not be from the skin around the neck, shoulders and head, but from below if there are any leaks around the neck area allowing the warm air to escape from inside your coat. The "chimney effect" relates to air, not heat inside your body. The chimney effect is the rising of warmer air, not heat within your body. Heat escaping from your skin is, for the most part, a product of skin surface area. Of course if you read the statement you quoted, you will see they are talking about
Your advice on keeping the core warm is very important, that helps keep everything else warm. Keeping extremities covered and insulated well, prevent loss there.