Abstract
BACKGROUND: Sleep disturbance is common in caregivers of older adults with memory disorders. Little is known, however, about the implications of caregivers' poor sleep with regard to their physical functioning. METHODS: In this cross-sectional study, we investigated the association between objectively measured sleep and self-reported physical functioning in 45 caregivers (mean age = 68.6 years) who completed the Beck Depression Inventory-II, the Medical Outcomes Study SF-36, and the Mini-mental State Examination, and wore an actigraph for at least three days. Our primary predictors were actigraphic sleep parameters, and our outcome was the SF-36 Physical Functioning subscale. RESULTS: In multivariate-adjusted linear regression analyses, each 30-minute increase in caregivers' total sleep time was associated with a 2.2-point improvement in their Physical Functioning subscale scores (unstandardized regression coefficient (B) = 2.2, 95% confidence interval (CI) 1.0-3.4, p = 0.001). In addition, each 10-minute increase in time awake after initial sleep onset was associated with a 0.5-point decrease on the Physical Functioning subscale, although this was not statistically significant (B = -0.5, 95% CI -1.1, 0.1, p = 0.09). CONCLUSIONS: Our findings suggest that shorter sleep duration is associated with worse self-reported physical functioning in caregivers. Longitudinal studies are needed to determine whether poor sleep predicts functional decline in caregivers.