Age-related sleep change

The sleep of a large group of healthy older men and women was studied in an effort to better understand the relationship between self-reported subjective and objectively measured sleep quality. We examined the baseline subjective and objective sleep quality of 150 healthy older (67.5±0.5) men (n=55) and women (n=95). Subjects were carefully screened to exclude sleep disorders and did not complain of significant sleep disturbance. Despite their noncomplaining status, significant proportions of both women (33%) and men (16%) endorsed Pittsburgh Sleep Quality Index (PSQI) scores of >5, a criterion indicative of significant sleep disturbance. When examined as a function of this criterion, objective sleep was significantly impaired with longer sleep latency, less total sleep time, and lower sleep efficiency, for the high-PSQI (H-PSQI) men compared to low-PSQI (L-PSQI) men. These L-PSQI versus H-PSQI differences were much weaker for women and disappeared completely in women on estrogen replacement therapy. This large group of healthy, noncomplaining older adults manifested significantly disturbed sleep relative to healthy younger subjects, indicating that while aging results in significant changes in sleep, it does not of necessity result in complaints of insomnia and that many healthy older individuals apparently adapt their perception of what is "acceptable" sleep. A considerable correspondence between subjective and objective sleep quality was observed for men but not for women, despite women more frequently endorsing the presence of significant sleep disturbance. This finding is provocative and suggests that what we consider objective measures of good-quality sleep may be appropriate for older men but that older women may be evaluating their sleep quality using other criteria.