Researchers have shown that laughter boosts blood flow, something that's good for the heart. University of Maryland cardiologists showed comedic clips of Kingpin and There's Something About Mary, and the opening sequence of Saving Private Ryan to twenty healthy subjects. According to the study, the laughter induced by the funny clips caused 50 percent more blood to flow in the subjects' brachial arteries than occurred while they viewed the stressful footage from Private Ryan. From Scientific American:
In fact, being light-hearted boosted blood flow about the same amount as light exercise or drugs that lower cholesterol. Drama-induced stress, on the other hand, cut that rate by as much as angry memories or mental calculations. "What that suggests, at the very least, is that laughter on a regular basis will undo some of the excess stress we face in our everyday lives," (researcher Michael) Miller notes. "Patients at risk for cardiovascular disease should loosen up a bit."