In re daytime sleepiness and mortality

To the Editor: In their monumental work on daytime sleepiness and mortality, Newman et al.1 overlook the possibility that many sleepy older people actually do nap in the afternoon. We had the opportunity to study the effect of daytime sleep (the siesta) on mortality in a longitudinal study of 70-year-olds in Jerusalem, Israel. We found that the report of the siesta doubled the risk of mortality over the ensuing 6.5 years, and that this risk was independent of many prevalent characteristics and risk factors2 Unlike the patients reported by Newman et al.,1 our patients did not nap because of nighttime sleep complaints. Actually, we found that the practice of the siesta was associated with a significantly higher nocturnal sleep satisfaction. We previously found,3, 4 like others,5 that, upon awakening from the siesta there is a marked increase in blood pressure and heart rate. Therefore, we hypothesized that, as there is clustering of cardiovascular events in the morning,6, 7 another sleep period during the day may add such a risk. The association in different populations, like ours who may be napping because of a life-long (or acquired) Mediterranean habit, and those who are fatigued, like the subjects studied by Newman et al.,1 or cognitively impaired elderly who were studied by Hays et al.,8 may lend support to our hypothesis. Editor's note: The above letter was sent to the author of the original article, and Dr. Newman's reply follows.