The superior sleep of healthy elderly nuns.

The nocturnal sleep structure of ten healthy elderly nuns was compared to that of ten healthy age-matched female controls. The nuns fell asleep more quickly and had less early morning awakening, as well as greater REM sleep time. These differences may reflect the more highly entrained life style of the nuns, including modest habitual sleep restriction (and thus accumulated sleep debt) of about one hour each night. The current findings, reviewed in relation to the sleep and aging literature, tend to support the concept that some of the effects of aging on sleep can be offset by attention to good "sleep hygiene," including careful entrainment of sleep schedule and modest habitual sleep restriction. However, age-related decrements in slow-wave sleep and sleep maintenance were not significantly better in the nuns.