A 2007 study from the Harvard School of Public Health, conducted with the University of Athens Medical School and the Hellenic Health Foundation, suggested that regular midday naps can significantly lower the risk of death from coronary heart disease. Published in the Feb. 12 issue of the Archives of Internal Medicine, the study followed 23,681 Greek participants aged 20 to 86, over six years.

Led by Dimitrios Trichopoulos, the Vincent L. Gregory Professor of Cancer Prevention, and Androniki Naska of the University of Athens Medical School, the study examined the role of cultural habits like the mid-day nap (mesimerianos hypnos in Greek), which had received little attention compared to dietary differences.

Participants reported whether they were taking midday naps and characterized them as either regular, three times a week for 30 or more minutes, or irregular, which would include those who napped once or twice a week for 30 or more minutes and those who napped more frequently but for less than a half an hour. Data on the participants’ physical activity, diet, health, smoking status, age, education level, socioeconomic status and other factors was also collected. By the end of the study period, 792 study participants had died—133 of them from coronary heart disease.

The Greek researchers found that occasional napping lowered the risk of coronary heart disease death by 12 percent, while regular napping— defined as napping three times per week for at least 30 minutes— lowered the risk by 37 percent. The greatest benefit appeared among working men. There weren’t enough deaths of working women during the study to allow statistical analysis.

“If confirmed by other investigations, these results would imply that a siesta could be added to the several means available for the control of coronary heart mortality, like healthy diets or cholesterol-lowering medications,” said Trichopoulos. “The magnitude of the effect appears to be considerable.”