Laugh and be well,” British poet Matthew Green wrote in 1737.

It turns out Green’s most famous poem, “The Spleen,” from which this line comes, offered good medical advice.

Researchers at the University of Maryland School of Medicine have documented, for the first time, that laughter is in fact good for the heart because it makes blood vessels work more efficiently. The study results, and those of an accompanying research paper reporting that depression can increase the risk of heart failure, were presented last week at the annual meeting of the American College of Cardiology.

Lead researcher, Michael Miller, director of preventive cardiology at the university in Baltimore, said laughter should not supplant exercise, which also increases blood flow, but should be added to one’s daily routine. He suggested 15 minutes of laughter daily and 30 minutes of exercise three times a week to improve heart health.

In their small study, Dr. Miller and his colleagues showed one humorous and one stressful movie clip to 20 healthy volunteers and then tested their blood flow, blood sugar levels and blood pressure. In 14 of the 20 volunteers, blood flow was reduced by more than one-third on average while watching the stressful clip, the opening scene from the World War II drama “Saving Private Ryan.” The funny film clip, from “Kingpin,” increased blood flow an average of 22 percent when 19 of the volunteers laughed.

The researchers specifically analyzed the lining of the blood vessels, called the endothelium, which is the first place where hardening of the arteries, a common form of heart disease is evident. They believe the relaxing of the endothelium was prompted by the release of nitric oxide. The compound relaxes blood vessels much like endorphins do during exercise.

“When you laugh, you have less wear on your joints and you don’t have to worry about calories from chocolate,” Dr. Millers said at the Orlando meeting.

Fortunately, recent studies have found that chocolate can prolong life and improve memory. So maybe a snack of chocolate candies is in order while watching Monty Python movies. It’s all in good health.

For as Sir Max Beerbohm, a British writer and illustrator known for his wit, wrote: “Strange when you come to think of it, that of all the countless folk who have lived before our time on this planet not one is known in history or in legend as having died of laughter.”