ARI SHAPIRO, HOST:
And now we have an update for you on the science of thirst. NPR's Jon Hamilton reports on special brain cells that appear to tell us when we want just plain water and when we might crave one of those fancy sports drinks.
JON HAMILTON, BYLINE: When you're sweating through a long workout, your body loses minerals as well as fluid. And Yuki Oka of Caltech says that produces a special kind of thirst.