Effects Of A Long-term Physical Activity Program On Accelerometry-based Sedentary Time In Older Adults

Abstract

INTRODUCTION: Older adults are one of the most sedentary age groups in the US. Excessive sedentary behavior is an independent risk factor for adverse health outcomes including diabetes, cardiovascular disease and metabolic syndrome. However, it remains unclear whether increasing moderate intensity physical activity modifies time spent in sedentary behaviors among older adults with functional limitations. PURPOSE: To determine the effects of a physical activity program on sedentary time in older adults. METHODS: The Lifestyle Interventions and Independence for Elders (LIFE) study was a multicenter, single-blinded randomized trial of 1,635 sedentary men and women, aged 70-89 years, who had functional limitations, defined as a score < 10 on the Short Physical Performance Battery. At baseline, participants were randomized to either a structured physical activity (PA) intervention or a successful aging health education (SA) program. The PA intervention consisted of 150 min/week of moderate intensity walking and lower extremity strength and balance training while the SA program consisted of health education workshops. An accelerometer captured total daily sedentary time (defined as less than 100 counts per minute), measured at baseline and 6, 12, and 24 month follow-up visits (FU). RESULTS: Among all participants, 1,276 (78.8 ± 5.3 years old) wore the accelerometer for 10 hours and for 3 days at baseline. At baseline, both intervention groups spent 10.7 ± 1.9 hours or 77.0% ± 8.1% of their day being sedentary. Using mixed linear modeling, the PA group, on average, engaged in 10.0 ± 2.9 (p<0.001) less daily sedentary minutes or 1.3% ± 0.4% (p<0.001) less daily sedentary time than the SA group over the course of 24 months. Results were adjusted for baseline sedentary time, accelerometer wear time, age, sex and clinical site. DISCUSSION: This study suggests that a program designed to increase moderate intensity physical activity among older adults also reduces sedentary time, but these effects were small. Funding: Supported by NIH/NIA Cooperative Agreement #UO1 AG22376 and NHLBI 3U01AG022376-05A2S