Abstract P128: Accelerometer-determined Moderate to Vigorous Physical Activity and the Cardiovascular Response to Stress in Children

Abstract

Background: Physical activity (PA) has been associated with lower cardiovascular reactivity in adults, but little data is available in children. The purpose of this study was to examine the relationship between PA and cardiovascular reactivity to stress in children. Methods: This study sample included children from the Oswego Lead Study (n=79, 46% female, 9-11 years old). Impedance cardiography was performed while children participated in a stress response protocol consisting of three stress tasks in random order, separated by 8-minute intertask rest periods. Change in heart rate (HR) and systolic and diastolic blood pressure (SBP and DBP) (from baseline to stress level) were standardized within each task, then averaged across tasks (zMean [[Unable to Display Character: ∆]]). Total peripheral resistance (TPR) was calculated using BP and cardiac output (CO); TPR = ([(SBP-DBP)/3] + DBP)/CO X 80. Percent change in TPR (from baseline to stress level) was standardized within each task, and then averaged across tasks (zMean %[[Unable to Display Character: ∆]]). Children were also asked to wear Actigraph accelerometers on their wrists for 3 days to measure intensity and duration of PA and sedentary time. Results: In multivariable regression models, moderate to vigorous (MV) PA was associated with a lower body mass index (BMI) percentile, lower resting heart rate (HR), and lower TPR response to stress (Table 1; all p < 0.05). After additional adjustment for BMI, MVPA was also associated with lower diastolic blood pressure response to stress (p < 0.05). Sedentary time was not associated with resting measures or cardiovascular responses to stress (data not shown). Conclusions: A modest relation was observed between MVPA and vascular reactivity to stress in children after accounting for the effect of BMI. These data provide confirmatory evidence that the promotion of PA recommendations for children are important for cardiovascular health.