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Water to Muscles

July 10, 2007

A listener asks: How does water get from your mouth to your tissues?


How your muscles drink. I’m Bob Hirshon and this is Science Update.

Dennis Jankowski of Manistee, Michigan, asked if we would explain how water gets from your mouth to your muscles. We turned to physiologist Hannah Carey, president of the American Physiological Society. She says when you drink water, it goes first to your intestines, or gut.

HANNAH CAREY (American Physiological Society and University of Wisconsin-Madison School of Veterinary Medicine):
And in a very simple process—osmosis—water diffuses across the gut lining and there are blood vessels right there inside your gut wall that are ready to take up the water.

From there, the bloodstream carries the water throughout the body, delivering it to tissues including your muscles and your brain, which need water to function. If you’re thirsting for the answer to a science question, call us at 1-800-why-isit or go to If we use it, you’ll win a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.