Show Details

Behind Thirst

August 2, 2007

A listener asks: What happens when we feel thirsty?


How thirst works. I’m Bob Hirshon and this is Science Update.

We know thirst is a signal that we need to drink more water, but what exactly causes thirst? Well, physiologist Hannah Carey of the American Physiological Society recently answered that question for us. She says that when your body doesn’t have enough water, special neurons in your brain get dehydrated and shrink a little. When that happens, those neurons become more active and start firing.

HANNAH CAREY (American Physiological Society):
That sends a neural signal to your pituitary gland to cause the release of hormones that stimulate you to drink more water.

Those hormones also tell your kidneys not to let too much water go. If you have a science question, call us at 1-800-why-isit. If we use it on the air, you’ll win a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.