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Caffeine Withdrawal

October 3, 2006

A listener asks: Why do I get a headache if I go without coffee?


Why giving up coffee hurts. I’m Bob Hirshon and this is Science Update.

Listener Monica Villa of Des Moines writes to ask what makes caffeine withdrawal hurt. We turned to American University psychologist Laura Juliano, who says caffeine constricts blood vessels in the brain. Over time, the brain adjusts to a person’s regular caffeine use by working extra hard to dilate those vessels.

LAURA JULIANO (American University):
But when they stop using caffeine, all of a sudden their body, which has been making these adjustments, now is continuing to make these adjustments because it doesn’t realize, in a sense, that caffeine isn’t going to be coming any time soon, and so that causes this very strong dilation of the blood vessels in the brain, and that can feel—does feel—like a very bad throbbing headache.

If a science question gives you a headache, call us at 1-800-why-isit. I’m Bob Hirshon, for AAAS, the science society.