Naps aren't generally included in the litany of good-for-your-heart lifestyle choices recommended for lowering cardiovascular risk, but they may soon be.
New research suggests a midday siesta may reduce a person's risk of death from heart disease, possibly by lowering stress levels.
The findings must be confirmed, but Dimitrios Trichopoulos, MD, a study author, tells WebMD there is little downside to taking naps -- and there could be big health benefits.
"The siesta is a victim of progress. Most of us aren't in the position to take a daily nap," he says. "But our research suggests that the practice could help protect the heart, and we need further studies to find out if this really is the case."
Part of the Culture
Trichopoulos says the research stemmed from the observation that heart disease death rates are lower in Mediterranean and Latin American countries where midday siestas are part of the culture.
His own earlier research in a Greek population provided weak evidence in favor of the nap hypothesis, but another, larger study, conducted in Costa Rica failed to show an association.
The newly published Greek study by Trichopoulos and colleagues from the Harvard School of Public Health in Boston, and Greece's University of Athens Medical School is the largest ever to examine the issue in a previously healthy population.
A total of 23,681 residents of Greece with no history of heart disease, stroke, or cancer at enrollment were followed an average of 6.3 years.
After trying to control for other heart disease risk factors, such as diet and physical activity levels, the researchers concluded that people who took naps at least three times a week for an average of at least 30 minutes were 37% less likely to die of heart disease than people who did not take regular naps.
Less frequent nappers had a 12% reduction in heart disease mortality, which was not considered statistically significant.
The perceived protective effect was stronger among working men than among men who were retired, suggesting, say the authors, that the stress-lowering effects of napping may explain the finding.
"The existence of a stronger inverse association among working men is compatible with the fact that occupational stress is common in many manual and nonmanual professions," the researchers wrote.
There were too few deaths among working women enrolled in the study to conduct a similar analysis.
The study is published in the Feb. 12 issue of The Archives of Internal Medicine.
The Mediterranean Influence
Even if a daily siesta does turn out to lower heart risk, it is only one of many explanations for why fewer Greeks than Americans die from heart attacks and strokes, Trichopoulos says.
His own research helped establish the cardio-protective benefits of the traditional Mediterranean diet -- rich in fruits, vegetables, beans, and grains; low in red meat.
Researchers attempted to control for the effects of diet, exercise, and other cardiovascular influences in the new study. But Trichopoulos acknowledges it is difficult to tease out all the features of the traditional Mediterranean lifestyle that play a role in protecting the heart.
Florida cardiologist Gerald Fletcher, MD, of the Mayo Clinic Jacksonville, tells WebMD the findings suggest there is more to learn about the impact of lifestyle on the heart.
"It makes sense that lowering stress levels with a daily siesta or even a semi-siesta could benefit the heart," he says. "We are increasingly recognizing the importance of sleep in cardiology."
Fletcher says even people who can't take midday naps can probably derive some benefit from sitting or lying quietly for five or 10 minutes sometime during the day.
"Even going out and sitting in the sunshine for a few minutes might bbeneficial," he says.
SOURCES: Nasha, A. Archives of Internal Medicine, Feb. 12, 2007; vol 167: pp 296-301. Dimitrios Trichopoulos, MD, professor of cancer prevention and epidemiology, Harvard School of Public Health, Boston; Department of Hygiene and Epidemiology, University of Athens Medical School, Athens, Greece. Gerald Fletcher, MD, cardiologist, Mayo Clinic Jacksonville, Jacksonville, Fla.
By Salynn Boyles
Reviewed by Louise Chang