We’ve explored one of the things our bodies do when they experience high temperatures, but what about when we get cold? When we’re outside in the blistering cold, we tend to shiver without control. But why do we shiver and how does it work?
Why do we shiver?
Shivering is our body’s mechanism of returning the body temperature to 98.6° Fahrenheit/37° Celsius from a lower temperature. Shivering increases your body temperature and attempts to prevent you from going into a state of hypothermia.
Shivering is basically our muscles contracting rapidly to generate heat.
How do we shiver?
We have thermoreceptors, little structures in our skin that detect temperatures, that relay a signal via the nervous system to a part of our brain, called the hypothalamus. This sends a different signal, using the nervous system, to our skeletal muscles (especially those that surround our vital organs) and tell them to contract rapidly. This causes an increase in heat production (up to 18x greater than usual!).
Your teeth chatter when you’re really cold for this reason; the muscles in your jaw are contracting.
Seeley, R.R., Stevens, T.D., and Tate, P. 2008. Anatomy and Physiology (8th ed.). pp. 307, 1012. New York: McGraw-Hill.