You’ve heard: “Grab a cup of coffee to relieve a headache.”
The Truth: Better make it two cups. Studies show that 200 milligrams of caffeine—about the amount in 16 ounces of brewed coffee—does provide relief from headaches, including migraines. Exactly how caffeine relieves headaches isn’t clear. But scientists do know that caffeine boosts the activity of brain cells, causing surrounding blood vessels to constrict. One theory is that this constriction helps to relieve the pressure that causes the pain, says Robert Shapiro, M.D., Ph.D., associate professor of neurology and director of the Headache Clinic at the University of Vermont Medical School.
However, relying on caffeine long-term can backfire. When regular coffee drinkers miss their daily caffeine fix, this is often associated with a rebound increase in blood flow to the brain. Increased blood flow means increased pressure and, as a result, “withdrawal headaches” can occur. Shapiro counsels headache sufferers to limit caffeine intake and use it only to relieve headaches.