bunrab | In cold weather, we lose over 40% of our body heat from our head

That includes when we are sleeping. Many people deal with this by pulling the covers up over their heads - which leads to carbon dioxide headaches in the morning. Most people seem to have forgotten the old idea of nightcaps - not the alcoholic kind, but the kind in "The Night Before Christmas" - "Ma in her kerchief and I in my cap, had just settled down for a long winter's nap." If you've never tried wearing a sleep cap, give it a try - it is amazing how much more comfortably one falls asleep if one's head is warm. (Feet too, but you all knew that!)

I won't even tell you about nose snoods - that's too silly.