Sedentary Behaviour And All Physical Activity Intensities Are Associated With Disease Risk

Abstract

PURPOSE. With evidence suggesting that physical activity (PA), sedentary behaviour (SB), including sleep duration, it is important to adopt an all encompassing lifestyle approach when assessing the influence of these behaviours on health. The aim of this study was to assess the relationship between PA, SB and sleep, measured concurrently in UK adults on various disease risk outcomes. METHODS. PA and SB were measured using an ActiGraph GT1M accelerometer over a period of 9 days, in a sample of 78 adults (62% female, BMI = 25.4 ± 4.4kg/m2, age = 38.3 ± 14.1). Time spent in bed and sleep duration were recorded throughout using a sleep diary. Participant's height, weight, BMI, body composition, waist circumference and blood pressure were taken at the outset. Associations between time spent in SB, and time in light and moderate-to-vigorous PA (MVPA), and the disease risk factors were analysed using correlation coefficients in PASW 18.0. RESULTS. The mean proportion of time spent in SB, light intensity PA, MVPA and time spent asleep over a 24 hour period were 48% (691.2 ± 84.8 mins), 20% (288 ± 76.1 mins), 3% (43.2 ± 24.8 mins) and 29% (417.6 ± 38.5 mins), respectively. Increased time in light intensity PA was associated with reduced BMI (r2 = 0.06), body fat (r2 = 0.06), waist circumference (r2 = 0.05) (all p < 0.05) and systolic (r2 = 0.10) and diastolic blood pressure (r2=0.20) (all p<0.05), whilst increased time in SB was associated with increased systolic (r2=0.09) and diastolic blood pressure (r2=0.20) (all p < 0.01). Increased time in MVPA was associated with reduced fat percentage (r2= 0.10, p<0.05). No significant associations were observed between time in bed and sleep duration with the disease risk factors. CONCLUSIONS. In the sample studied, increased time spent in light intensity PA as well as MVPA and less sedentary behaviour were all associated with less risk for disease. Although evidence suggests that for beneficial effects on health, moderate intensity activity is needed, this study adds to the emerging limited evidence highlighting the potential added beneficial effects of light intensity PA on health. Programmes focussing on moving people from less sedentary behaviour to any level of intensity of physical activity could therefore be useful in reducing risk for chronic disease.