Fainting: Frightening, but seldom serious

Learn why fainting occurs and when you should seek medical attention.

One minute you're feeling a bit woozy; the next thing you know, you're flat on your back wondering what happened. No matter what you call it — swooning, passing out, or fainting — the experience is surprisingly common. About a third of people say they've fainted at least once.

Defined as a sudden, temporary loss of consciousness, fainting occurs when something interrupts blood flow to the brain. Doctors call it syncope, which comes from a Greek word meaning "contraction" or "cut off." Although often harmless, fainting can cause injuries and sometimes signals a problem with the heart or circulatory system.