JERUSALEM, ISRAEL. There is ample evidence that strokes and heart attacks occur more frequently during the morning. It is believed that this is because the process of waking up causes hormonal changes and changes in blood pressure and heart rate which can all be detrimental to heart function. Now researchers at the Hadassah University Hospital report that waking up from an afternoon nap (siesta) may have similar effects. Their study involved 455 70-year-old residents of Jerusalem. The researchers found that the mortality over a 6.5-year period was almost twice as high (20 per cent vs. 11 per cent) among study participants who usually had a siesta as among those who did not. The difference was particularly noticeable among participants who died from cardiovascular events. Among the siesta takers 9 per cent died during the observation period as compared to 4 per cent among those who took no siesta. This correlation held true even when adjusting for previous heart attacks, blood pressure, physical exercise level, duration of night sleep, smoking status, cholesterol level, and the presence of cerebrovascular disease. The researchers conclude that people who regularly take an afternoon nap have a higher mortality rate than people who do not.
Bursztyn, Michael, et al. The siesta in the elderly: risk factor for mortality? Archives of Internal Medicine, Vol. 159, July 26, 1999, pp. 1582-86