Siestas reduced coronary mortality by more than 30% in this prospective Greek study, but confounding might explain the association.
Observational studies have suggested that coronary heart disease mortality rates are lower in certain Mediterranean countries because of the common practice of taking siestas. Researchers assessed the effect of siestas on coronary mortality in a prospective study of 23,681 participants in Greece (age range, 20–86) who were free of known CHD, stroke, and cancer at enrollment. Researchers obtained baseline data on daytime napping habits, diet, physical activity, smoking, and body-mass index.
During a mean follow-up of 6.3 years, 133 deaths were attributed to CHD. After controlling for potential confounders, researchers found that compared with participants who did not take siestas, those who reported siestas of any frequency and duration had a coronary mortality ratio of 0.66, and those who reported systematic siestas (at least 3 times per week for at least 30 minutes each) had a mortality ratio of 0.63.
Comment: In this prospective Greek study, taking siestas was associated with reduced coronary mortality. Although we may be tempted to prescribe such an intervention to everyone, it is unclear whether this association reflects cause-and-effect or just residual confounding by unidentified variables.
— Jamaluddin Moloo, MD, MPH
Published in Journal Watch General Medicine February 20, 2007
Naska A et al. Siesta in healthy adults and coronary mortality in the general population. Arch Intern Med 2007 Feb 12; 167:296-301.