eli5 When I’m in bed on a cold night, if I put my arm out of the covers it quickly gets really cold and uncomfortable. However, my head is out of the covers all night, resting on a pillow, and doesn’t get cold at all. Why?

Question

eli5 When I’m in bed on a cold night, if I put my arm out of the covers it quickly gets really cold and uncomfortable. However, my head is out of the covers all night, resting on a pillow, and doesn’t get cold at all. Why?

In: 49

Answer 1

Your face is warmed by the blood flow underneath it. It cools but at a rate the underlying blood flow CAN keep up with.

An arm cools by blood flow that is slower when resting. When active, plenty of blood flow to stay warm.