Background: Midday napping (siesta) is common in populations with low coronary mortality, but epidemiological studies have generated conflicting results. We have undertaken an analysis based on a sizable cohort with a high frequency of napping and information on potentially confounding variables including reported comorbidity, physical activity, and diet.
Methods: Among participants in a general population cohort (the Greek European Prospective Investigation into Cancer and Nutrition [EPIC] cohort), 23 681 individuals who at enrollment had no history of coronary heart disease, stroke, or cancer and had complete information on frequency and duration of midday napping, as well as on potentially confounding variables, were followed up for a mean of 6.32 years. Data were modeled through Cox regression, using time to coronary death and treating deaths from other causes as censoring events as outcomes.
Results: Among men and women, when controlling for potential confounders and using those not taking siesta as a referent category, those taking a siesta of any frequency or duration had a coronary mortality ratio (MR) of 0.66 (95% confidence interval [CI], 0.45-0.97). Specifically, those occasionally napping had a 12% lower coronary mortality (MR, 0.88; 95% CI, 0.48-1.60), whereas those systematically napping had a 37% lower coronary mortality (MR, 0.63; 95% CI, 0.42-0.93). Among men, the inverse association was stronger when the analysis was restricted to those who were currently working at enrollment, whereas among women, a similar analysis was not possible because of the small number of deaths.
Conclusion: After controlling for potential confounders, siesta in apparently healthy individuals is inversely associated with coronary mortality, and the association was particularly evident among working men.