Association of Physical Activity, Sedentary Behavior, and Sleep With Unhealthy Aging: Consistent Results for Device-Measured and Self-reported Behaviors Using Isotemporal Substitution Models.

BACKGROUND: We examined the association of time allocation among physical activity (PA), sedentary behavior (SB), and sleep with unhealthy aging (UA), using both accelerometry and self-reports.
METHOD: We used cross-sectional data from 2312 individuals aged 65 years and older. Physical activity, SB, and sleep were ascertained by both wrist accelerometers and validated questionnaires, and UA was measured with a 52-item health-deficit accumulation index. Analyses used isotemporal substitution linear regression models.
RESULTS: Less deficit accumulation was observed when the distribution of activities was 30 min/d less of SB and 30 min/d more of PA for both accelerometer (fully adjusted β [95% CI]: -0.75 [-0.90, -0.61]) and self-reports (-0.55 [-0.65, -0.45]), as well as less long sleep and more PA (accelerometer: -1.44 [-1.86, -1.01]; self-reports: -2.35 [-3.35, -1.36]) or more SB (accelerometer: -0.45 [-0.86, -0.05]; self-reports: -1.28 [-2.29, -0.28]), less normal sleep and more moderate-to-vigorous PA (accelerometer: -1.70 [-2.28, -1.13]; self-reports: -0.65 [-0.99, -0.31]), and less accelerometer light PA and more moderate-to-vigorous PA (-1.62 [-2.17, -1.07]). However, more deficit accumulation was observed when less sleep was accompanied by either more SB or more light PA in short sleepers. Self-reports captured differential associations by activity: walking appeared to be as beneficial as more vigorous activities, such as cycling or sports, and reading was associated with less UA than more mentally passive SBs, such as watching TV.
CONCLUSIONS: More PA was associated with less UA when accompanied by less SB time or sleep in long/normal sleepers, but not in short sleepers, where the opposite was found. Accelerometry and self-reports provided consistent associations.