According to new research on napping, a little midday snooze seems to reduce risks for fatal heart problems, especially among men.

In the largest study to date on the health effects of napping, researchers tracked 23,681 healthy Greek adults for an average of about six years. Those who napped at least three times weekly for about half an hour had a 37 percent lower risk of dying from heart attacks or other heart problems than those who did not nap.

Most participants were in their 50s, and the strongest evidence was in working men, according to the study, which appears in Monday's issue of Archives of Internal Medicine.

The researchers said naps might benefit the heart by reducing stress, and jobs are a common source of stress.

It is likely that women reap similar benefits from napping, but not enough of them died during the study to be sure, said Dr. Dimitrios Trichopoulos, the study's senior author and a researcher at Harvard University and the University of Athens Medical School. Heart problems killed 48 women who were studied, six of them working women, compared with 85 men, including 28 working men.

A daytime siesta has long been part of many cultures, especially those in warmer climates. Mediterranean-style eating habits featuring fruits, vegetables, beans and olive oil have been credited with contributing to relatively low rates of heart disease in those countries, but the researchers wanted to see if napping also plays a role.

The research team studied people ages 20 to 86, who were generally healthy when the study began.