NOCTURNAL ACTIVITY AND IMMOBILITY ACROSS AGING (50-98 YEARS) IN HEALTHY-PERSONS

Objective: To measure the influence of age on measures of nocturnal ac tivity and immobility in 100 healthy subjects aged 50 to 98 years. Des ign: Cross-sectional study. Setting: Urban population in Leiden. Recor dings were performed at home while the subjects maintained their habit ual 24-hour pattern of activities. Participants: 100 subjects without a history of major medical disorders and a normal neurological examina tion and performance-oriented assessment of gait (Tinetti). Measuremen ts: Motor activity was recorded during six successive nights with a wr ist-worn activity monitor. The occurrence of supra-threshold motor act ivity was recorded over 15-second epochs. A questionnaire was used to evaluate sleep habits and the occurrence of sleep disturbances. Four m ean measures reflecting activity or immobility during the nocturnal pe riod were calculated for each subject. Results: Only one out of four m easures, (ie, the nocturnal proportion of time with movement, increase d with age for females. For males, no age effects emerged. The mean du ration of nocturnal immobility periods was higher in females than in m ales. Also, for females, the use of hypnotics increased with successiv e decades. Sex and the use of hypnotics were significantly related to the mean duration of immobility periods. Conclusion: If care is taken not to confound aging with illness, measures of nocturnal activity and immobility reveal only marginal effects of aging.