YOUR BODY VS THE COLD
Every cell in your body is involved in complex chemical reactions which make a little bit of heat. Busier parts of the body, like your liver, make more heat, and your blood system works hard to move that heat around and keep all of you at a comfortable 37 ˚ C so everything works at its best potential.
Evolution has given us a few tricks to help us maintain that temperature.
Sweating is pretty effective at cooling us when we’re too hot, but we’re not so good at coping when we’re too cold.
Shivering is the best defence we have naturally, but it’s not particularly efficient. The only other trick we have is to shut down some of the blood to our extremities. The body would readily sacrifice your hands and feet to save its core, so if you’re getting cold hands, it’s usually a sign you’re not wearing enough on your body.