Heart disease is no laughing matter. Every year, nearly 1 million Americans die from some form of cardiovascular disease and about 62 million Americans suffer from a heart-related condition such as coronary heart disease or high blood pressure, according to the American Heart Association. However, if researchers have their way, many of these individuals will soon have the last laugh.

In March, Dr. Michael Miller, director of the Center for Preventative Cardiology at the University of Maryland School of Medicine in Baltimore, reported that laughter pumps up heart health. "We are learning that there is a lot closer heart-mind-body link than previously understood," he says. "Researchers have scrutinized negative stressors on the heart — depression, hostility and bereavement, for example — but haven't looked as closely at positive influences."

That's changing. Miller, who examined 20 healthy volunteers, looked at how blood vessels react when participants watched movie clips that were either humorous (such as "King Pin") or stressful (such as the opening scene of "Saving Private Ryan"). He found that blood flow increased by an average of 22 percent in 19 of the 20 participants when they laughed, and decreased by 35 percent in 14 of the 20 participants when they tensed up. A previous study Miller conducted in 2000 found that those with heart disease are less likely to find everyday situations funny — such as someone spilling a drink on them at a restaurant.