Here is footage taken using the military spec Selex Merlin thermal imaging camera of a shirtless man in the Scottish highlands during winter. The point is to show how fast humans lose the heat on their body when their bare skin is exposed to the bitter blistering cold. When he first takes off his clothes, you can see that his body is all red. Warm! But then as time passes and snow hits him, his body turns yellow and then green. Cold!