The association between sedentary behaviour, moderate-vigorous physical activity and frailty

Abstract

This thesis examined the association between sedentary behaviour, moderate-vigorous intensity activity (MVPA) and frailty using cross-sectional data in 50+year olds from the 2003-2006 National Health and Nutrition Examination Surveys. We constructeda modified frailty phenotype and a frailty index and found that both measures confirmed previously established characteristics of frailty scales. The frailty index could predict adverse outcomes even among those identified as robust by the phenotype suggesting it may be a more sensitive measure at lower levels of frailty. The overall sample engaged in about 8.5 hours of sedentary behaviour each day, with frail individuals being more sedentary than non-frail individuals. Non-frail individuals demonstrated higher levels of sedentary behaviour on Sundays and decreasing MVPA throughout the week as well as low MVPA in the evenings.High sedentary behaviour and low MVPA were independently associated with higher levels of frailty, poor self-reported health, high ADL disability and higher healthcare usage.