The association between sedentary behaviour, moderate-vigorousphysical activity and frailty in NHANES cohorts

Objectives: (1) To examine how sedentary behaviour and moderate-vigorous (MVPA) are each experi-enced during the day across different levels of frailty; (2) estimate and compare the extent to whichhigh levels of sedentary behaviour and low levels of MVPA are associated with increased frailty andself-reported health, disability and healthcare utilization.Methods: Community dwelling adults aged 50+ from the National Health and Nutrition ExaminationSurvey (2003-2004; 2005-2006). Frailty was measured with the frailty index and physical activity wasmeasured using ActiGraph accelerometers.Results: On average, people engaged in about 8.5 h of sedentary behaviour each day. The most frail individ-uals were more sedentary and less likely to meet weekly MVPA guidelines (9.57 h/day; 8.3%) than non-frailindividuals (8.18 h/day; 1.1%; p < 0.001). Frail individuals failed to demonstrate the patterns of the health-ier individuals-higher levels of sedentary behaviour on Sundays and in the evenings and decreasingMVPA throughout the week. High sedentary behaviour and low MVPA were independently associatedwith higher levels of frailty, poor self-reported health, high ADL disability and higher healthcare usage.Conclusions: Many people over the age of 50, and most of those who are frail, were highly sedentarywith very few meeting the recommended weekly levels of MVPA. Sedentary behaviour and MVPA wereindependently associated with frailty and adverse health outcomes in middle to older aged adults. Futureresearch should focus on a longitudinal study to determine the temporal relationship between sedentarybehaviour and frailty.