Even one extra hour of sleep a night could make the difference between a healthy heart and a heart attack.
Researchers at the University of Chicago checked the heart arteries of nearly 500 people over a period of five years. They say they were shocked to discover that the longer that people slept each night, the less chance they had of suffering from clogged heart arteries.
If they slept eight hours or more, the risk was just 6 percent. But if they slept just five hours or less, the risk jumped to 27 percent. The researchers still don't know why less sleep leads to clogged arteries. One theory is sleep reduces the amount of stress hormone called cortisol, which can affect heart arteries.
The study is in this Wednesday's Journal of the American Medical Association.
