The association between bouts of moderate to vigorous physical activity and patterns of sedentary behavior with frailty.

OBJECTIVES: To determine if bouts of moderate-vigorous physical activity (MVPA) and patterns of sedentary behavior are associated with frailty.

METHOD: Accelerometry from community-dwelling adults ≥50 years old (n = 2317) enrolled in the 2003-04 and 2005-06 National Health and Nutrition Examination Survey were used. Bouted (≥10 min) and sporadic (<10 min) durations of MVPA were analyzed based on meeting 0%, 1-49%, 50-99%, and ≥100% of physical activity guidelines (150 min/week of MVPA). Prolonged sedentary behavior were bouts lasting ≥30 min. Breaks from sedentary behavior were defined as any ≥1 min interruption in sedentary behavior. Average intensity (counts/min) and duration (minutes) during breaks were also analyzed. Frailty was measured with a 46-item frailty index.

RESULTS: Multivariable linear regression models adjusting for age, sex, education, ethnicity, income, marital status, smoking, alcohol consumption, body mass index, total sedentary time and accelerometer wear time indicated that meeting any percentage of the activity guidelines with bouted and sporadic MVPA was associated with reduced frailty. This relationship peaked at meeting 50-99% of guidelines and was associated with a 1.5 and 2.0 point reduction in the frailty index for bouted and sporadic MVPA, respectively. Two additional prolonged sedentary behavior bouts/day were associated with an additional frailty index deficit while every additional 100 cpm in average break intensity and every 2 min in average break duration were associated with one less deficit. Total sedentary breaks were not associated with frailty.

CONCLUSION: These population-level data give justification for determining if interventions which target short bouts of MVPA and interrupting prolonged, uninterrupted time spent in sedentary behaviors can treat or prevent frailty worsening.