The siesta in the elderly - Risk factor for mortality?

Background: During the siesta, blood pressure declines like it does during night sleep. Because cardiovascular and cerebrovascular events cluster during the morning hours, when hemodynamic changes from nocturnal baseline are maximal, we hypothesized that an additional sleep period during the day (the siesta) may increase cardiovascular and cerebrovascular events, and thus mortality. Methods: A prospective population-based cohort study of 455 70-year-old residents of Jerusalem, Israel, using self-reported siesta at baseline and 6 1/2 years of total mortality data. Results: The prevalence of the practice of the siesta was 60.7%. It was more prevalent among men than women (68% vs 51%, P < .001) and in survivors of previous myocardial infarction than in these without previous myocardial infarction (78% vs 58%, P = .009). After 6 1/2 years of follow-up (1990-1996), 75 subjects died. For those who practiced the siesta, total mortality was 20% vs 11% for those who did not (P = .01; risk odds ratio, 2.0; 95% confidence interval, 1.1-3.4). In a multiple logistic regression model that included several lifestyle descriptors, risk factors, and diseases, the siesta remained predictive of mortality (P = .03; risk odds ratio, 2.1; 95% confidence interval, 1.1-3.9). Conclusions: The siesta seems to be an independent predictor of mortality. It is still unknown whether this association is causal.