The relationship between objectively measured physical activity, sedentary time, and vascular health in children

Abstract

Background Physical activity (PA) is beneficially associated with arterial compliance in adults; however, whether this association persists in children is unclear. We examined the cross-sectional relationship of PA and sedentary time with arterial compliance in children. Methods Large and small artery compliance was determined by diastolic pulse contour analysis in 102 children aged 8-11 years (43 boys). We used accelerometers and age-specific cut points to classify activity as sedentary, light, or moderate-to-vigorous (MVPA). We also categorized MVPA according to bout length (0-5, 5-10, 10-20, and 20 min). Hierarchical linear regression examined: (i) the contribution of activity to large and small artery compliance (controlling for body surface area, systolic blood pressure, and body mass index (BMI)) and (ii) whether bouted MVPA was associated with arterial compliance independent of total MVPA. Results Activity variables did not explain any additional variance in large artery compliance beyond that captured by body surface area, BMI, and systolic blood pressure (P = 0.118 to P = 0.990). Light activity and MVPA explained an additional 5.8% (P = 0.003) and 2.7% (P = 0.043) of the variance in small artery compliance. MVPA accumulated in bouts was not significantly associated with small artery compliance after controlling for the total volume of MVPA (P = 0.784 to P = 0.923). Conclusions Objectively measured PA is associated with small, but not large artery compliance in children aged 8-11 years. Future research should explore the influence of bout frequency and the effect of a PA intervention on arterial compliance. © 2012 American Journal of Hypertension, Ltd.