Gender differences in the sleep of middle-aged individuals.

The study was designed to investigate gender differences in the sleep-wake patterns of healthy middle-aged individuals in their home environment. Polysomnography showed that daytime napping was more common in men than in women. Men had lower sleep efficiency index and experienced more stage 1 sleep. Males had significantly less stages 3 + 4 sleep, less stage REM sleep, and more transitions to wake from REM sleep. Men could not maintain stage REM as well as women. This study indicates that the gender differences in the sleep-wake patterns have appeared in a group of middle-aged individuals.