London: Laughter may be as beneficial as a good diet and exercise for patients with heart disease, researchers say. A 'belly laugh' improves blood flow, a new study has found.

When volunteers watched funny segments from the film there’s something about Mary their blood vessels expanded. But when they were shown scenes of distress from Saving Private Ryan their blood vessels narrowed, constricting blood flow to the heart.

"The magnitude of change we saw after laughing was similar to the benefit we might see with aerobic exercise," a daily quoted Prof Michael Miller, of the University Of Maryland School Of Medicine, as saying.

"It is very possible that laughing on a regular basis may be useful to incorporate as part of an overall healthy lifestyle to prevent heart disease. In other words, eat your veggies, exercise and get a good belly laugh every day," he added.