10-year changes in accelerometer-based physical activity and sedentary time during midlife: CARDIA Study

Abstract

To describe 10-year changes in accelerometer-determined physical activity (PA) and sedentary time in a midlife cohort, within and by race/sex groups. Coronary Artery Risk Development in Young Adults participants (n = 962) who wore the accelerometer with valid wear (≥4 of 7 days, ≥10 hours per day) at baseline (2005-06; ages 38-50; ActiGraph 7164) and 10-year follow-up (2015-16; ages 48-60; ActiGraph wGT3X-BT). Data were calibrated to account for accelerometer model differences. Participants (aged 45.0 ± 3.5 years at baseline) experienced reductions in accelerometer counts overall [-65.5 (10.2) ct·min·d^-1], and within race/sex groups (all p < 0.001). Sedentary time increased overall [37.9 (3.7) min∙d^-1], and within race/sex groups, while light intensity PA [-30.6 (2.7) min∙d^-1] and moderate to vigorous intensity PA both declined overall [-7.5 (0.8) min∙d^-1], and within race/sex groups (all p < 0.001). Significant differences in 10-year change estimates were noted by race/sex groups for accelerometer counts, sedentary time, and moderate to vigorous intensity PA bouts with black men experiencing the greatest reductions in PA compared to other groups. PA declines during midlife were characterized by reductions in light intensity PA with increases in sedentary time, which may have important health consequences. Targeted efforts are needed to preserve PA, regardless of intensity level, across midlife.