Replacing sedentary behaviour with physical activity reduces BMI
Replacing sedentary behaviour (SB) with physical activity, regardless of intensity, appears to have a positive impact on body mass index (BMI) independent of age, reveals a new study from New Zealand.
Secondary analysis of accelerometer data of 1,812 children (mean age 13.42±0.11 years; 51.9 percent male) showed that SB was significantly inversely associated with BMI across all age groups (p<0.05) except for the 20 to 24 age group. This was obtained from the model that accounted for all covariates.
Replacing 60 minutes of SB with the same amount of moderate to vigorous physical activity (MVPA) per day resulted in significant reductions in BMI in the 5 to 9 (regression coefficient, -1.255; 95 percent CI, -1.531 to -0.980), 10 to 14 (regression coefficient, -1.379; -1.699 to -1.060) and 15 to 19 (regression coefficient, -1.429; -1.767 to -1.091; p<0.001 for all) age groups.
BMI was also significantly reduced even if SB was replaced with the same amount of light intensity physical activity (LPA) in the 5 to 9 (regression coefficient, -0.270; -0.371 to -0.169; p<0.001), 10 to 14 (regression coefficient, -0.172; -0.278 to -0.066; p<0.05) and 15 to 19 (regression coefficient, -0.216; -0.331 to -0.101; p<0.001) age groups.
In the 20 to 24 age group, 30 minutes of SB per day were replaced by the same amount of physical activity. Reductions in BMI were statistically significant only when MVPA (regression coefficient, -1.047; -1.332 to -0.763; p<0.001) and not LPA was employed.