The association between sedentary behaviour, moderate–vigorous physical activity and frailty in NHANES cohorts

Highlights

• Many people over the age of 50, and most of those who are frail, are highly sedentary.

• Frail individuals fail to demonstrate the physical activity patterns that were seen in the non-frail.

• Sedentary behaviour and MVPA were associated with frailty and other adverse health outcomes.

Abstract

Objectives

(1) To examine how sedentary behaviour and moderate–vigorous (MVPA) are each experienced during the day across different levels of frailty; (2) estimate and compare the extent to which high levels of sedentary behaviour and low levels of MVPA are associated with increased frailty and self-reported health, disability and healthcare utilization.

Methods

Community dwelling adults aged 50+ from the National Health and Nutrition Examination Survey (2003–2004; 2005–2006). Frailty was measured with the frailty index and physical activity was measured using ActiGraph accelerometers.

Results

On average, people engaged in about 8.5 h of sedentary behaviour each day. The most frail individuals were more sedentary and less likely to meet weekly MVPA guidelines (9.57 h/day; 8.3%) than non-frail individuals (8.18 h/day; 1.1%; p < 0.001). Frail individuals failed to demonstrate the patterns of the healthier individuals—higher levels of sedentary behaviour on Sundays and in the evenings and decreasing MVPA throughout the week. 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.

Conclusions

Many people over the age of 50, and most of those who are frail, were highly sedentary with very few meeting the recommended weekly levels of MVPA. Sedentary behaviour and MVPA were independently associated with frailty and adverse health outcomes in middle to older aged adults. Future research should focus on a longitudinal study to determine the temporal relationship between sedentary behaviour and frailty.

Introduction

Despite the known benefits of physical activity [1], [2], physical activity levels have declined as the technological age has arrived [3]. Older adults have much lower levels of physical activity compared to younger adults [4]. While it has been reported that frail older adults, those at an increased vulnerability to adverse health outcomes [5], [6], tend to be more inactive than non-frail individuals of the same age [7], this evidence is limited and usually focuses on the overall levels of physical activity [8]. An examination of whether patterns of physical activity (such as intensity, day of the week and time of day) differ amongst individuals with varying levels of frailty may provide an understanding of where we need to target interventions [9].

Research on low levels of physical activity and adverse health outcomes has focused mainly on moderate–vigorous physical activity (MVPA), activities in which the individual exerts greater than 3 metabolic equivalents (METS) including swimming, bicycling, running or hiking [1], [2]; whereas research on the association between sedentary behaviour and adverse health outcomes is limited. Sedentary behaviours such as TV viewing, work, sitting, and driving are linked to poor health outcomes including cardiovascular problems, metabolism, cancer and mortality [10], [11]. This association, albeit attenuated, remains even in those who meet the recommended level of MVPA [10]. No studies yet have examined the direct and independent impacts of MVPA and sedentary behaviour on frailty. The objectives of this study are first, to examine how sedentary behaviour and moderate–vigorous activity are each experienced during the day across different levels of frailty and second, to estimate and compare the extent to which high levels of sedentary behaviour and low levels of MVPA are associated with increased frailty and other domains of health including self-reported health, disability and healthcare utilization.