Objective light-intensity physical activity associations with rated health in older adults

Abstract

The extent to which light-intensity physical activity contributes to health in older adults is not well known. The authors examined associations between physical activity across the intensity spectrum (sedentary to vigorous) and health and well-being variables in older adults. Two 7-day assessments of accelerometry from 2005 to 2007 were collected 6 months apart in the observational Senior Neighborhood Quality of Life Study of adults aged >65 years in Baltimore, Maryland, and Seattle, Washington. Self-reported health and psychosocial variables (e.g., lower-extremity function, body weight, rated stress) were also collected. Physical activity based on existing accelerometer thresholds for moderate/vigorous, high-light, low-light, and sedentary categories were examined as correlates of physical health and psychosocial well-being in mixed-effects regression models. Participants (N = 862) were 75.4 (standard deviation, 6.8) years of age, 56% female, 71% white, and 58% overweight/obese. After adjustment for study covariates and time spent in moderate/vigorous physical activity and sedentary behavior, low-light and high-light physical activity were positively related to physical health (all P < 0.0001) and well-being (all P < 0.001). Additionally, replacing 30 minutes/day of sedentary time with equal amounts of low-light or high-light physical activity was associated with better physical health (all P < 0.0001). Objectively measured light-intensity physical activity is associated with physical health and well-being variables in older adults.

Figure 1.

Selected physical activity intensity thresholds and 3 types of regression models used to test associations with health metrics in the Senior Neighborhood Quality of Life Study, United States, 2005–2007. Single activity models tested the “total effect” of each threshold, unadjusted for activity in other thresholds. Partition models tested the “unique effect” of each threshold adjusted for activity in other thresholds. Isotemporal substitution models tested the “substitution effect” of each threshold holding time constant. DRP, parameter dropped from model; MVPA, moderate/vigorous physical activity; SED, sedentary; >, no upper threshold set.