I agree a warm fleece hat and other appropriate clothing can go a long way in preventing or delaying the onset of hypothermia. I would consider them an essential and primary line of defense.

Likewise, I consider having energy sources to increase my changes of survival an important basic. I was unable to copy the section of this chart I wanted to include to support my point of view, but if you go to this web site and look at the chart, you will see that in early stage hypothermia, warm sweet liquids and high-energy foods are suggested. Pete

http://www.hypothermia.org/fieldchart.htm