Why Do We Shiver When We Are Cold?

When you are cold, your body tries to make you warmer by making you shake. This shaking is called shivering. It might seem like a weird waste of energy, but it actually helps create heat.

Think about rubbing your hands together when they are freezing. The friction makes them warm up. Your body does something similar on a much bigger scale. When tiny muscles inside you move back and forth very quickly, they produce warmth.

Your brain is like the control center of your house. When it feels that the outside temperature has dropped, it sends a message to your muscles. The message says, "Start shaking!" Your muscles then contract and relax in rapid succession. This constant movement uses up energy from your food and turns it into heat. You might notice you feel hungry after shivering because your body is burning through its fuel supplies to keep that heater running.