Abstract
OBJECTIVES: To evaluate the effect of hospitalizations on patterns of sedentary and physical activity time in mobility-limited older adults randomized to structured physical activity or health education. DESIGN: Secondary analysis of investigator-blinded, parallel-group, randomized trial conducted at 8 U.S. centers between February 2010 and December 2013. PARTICIPANTS: Sedentary men and women aged 70 to 89 at baseline who wore a hip-fitted accelerometer 7 consecutive days at baseline and 6, 12, and 24 months after randomization (N=1,341). MEASUREMENTS: Participants were randomized to a physical activity (PA; n = 669) intervention that included aerobic, resistance, and flexibility training or to a health education (HE; n = 672) intervention that consisted of workshops on older adult health and light upper-extremity stretching. Accelerometer patterns were characterized as bouts of sedentary (<100 counts/min; ≥1, ≥10, ≥30, ≥60 minute lengths) and activity (≥100 counts/min; ≥1, ≥2, ≥5, ≥10 minute lengths) time. Each participant was categorized as having 0, 1 to 3, or 4 or more cumulative hospital days before each accelerometer assessment. RESULTS: Hospitalization increased sedentary time similarly in both intervention groups (8 min/d for 1-3 cumulative hospital days and 16 min/d for ≥4 cumulative hospital days). Hospitalization was also associated with less physical activity time across all bouts of less than 10 minutes (≥1: -7 min/d for 1-3 cumulative hospital days, -16 min/d for ≥4 cumulative hospital days; ≥2: -5 min/d for 1-3 cumulative hospital days, -11 min/d for ≥4 cumulative hospital days; ≥5: -3 min/d for 1-3 cumulative hospital days, -4 min/d for ≥4 cumulative hospital days). There was no evidence of recovery to prehospitalization levels (time effect p >.41). PA participants had less sedentary time in bouts of less than 30 minutes than HE participants (-8 to -10 min/d) and more total activity (+3 to +6 min/d), although hospital-related changes were similar between the intervention groups (interaction effect p >.26). CONCLUSION: Participating in a PA intervention before hospitalization had expected benefits, but participants remained susceptible to hospitalization's detrimental effects on their daily activity levels. There was no evidence of better activity recovery after hospitalization. J Am Geriatr Soc 67:261-268, 2019.