A FIELD-STUDY OF AGE AND GENDER DIFFERENCES IN HABITUAL ADULT SLEEP

The sleep of 52 healthy paid subjects (23 male) divided into three age -bands (20-34, 35-49 and 50-70 y) were recorded at night in their home s for a total of 190 subject-nights while following their normal daily activities and habitual sleep-wake schedule. Then was a shortening in both nocturnal total sleep period and total sleep time (TST) with age , the oldest group sleeping 46 min less than the youngest. Also, the m id-point of sleep occurred 32 min earlier in the oldest group compared with the youngest group. The reduction in TST with age was due, in pa rt, to increased wake periods within sleep. The youngest subjects show ed more Movement Time which progressively decreased with age while the amount of stage 1 increased with age. The amount of slow-wave sleep ( SWS, stages 3 + 4) was reduced, stage 4 was more than halved, while RE M was slightly reduced with age. There were far fewer significant gend er differences in the sleep variables: males, particularly in the midd le and oldest age bands, had more stage 1 than females, while females had more SWS, particularly stage 3, than males. In general, despite re latively limited subject selection criteria, there was good agreement with previous laboratory-based normative sleep values for the effect o f age and gender.