Exercise effects on arterial stiffness and heart health in children with excess weight: The SMART RCT.

Abstract

IntroductionChildhood obesity and inactivity are associated with cardiovascular risk. Evidence is limited for exercise effects on arterial health in children.MethodsOne hundred seventy-five inactive children with overweight or obesity (8–11 years, ≥85th percentile BMI, 61% female, 87% Black, 73% with obesity) were randomized to an 8-month daily after-school aerobic exercise program (40 min/d, n=90) or a sedentary control condition (n=85). Carotid-femoral pulse wave velocity (PWV, primary outcome, arterial stiffness), fitness, adiposity, blood pressure (BP), glucose, insulin resistance, lipids, and C-reactive protein were measured at baseline and posttest (8 months). Adiposity, fitness, and BP were measured again at follow-up, 8–12 months later. Intent-to-treat analyses were conducted using mixed models.ResultsThe study had 89% retention, with attendance of 59% in exercise and 64% in the control condition, and vigorous exercise participation (average heart rate 161±7 beats/min). Compared to controls, the exercise group had twice the improvement in fitness (VȮ2 peak, 2.7 (95% CI 1.8, 3.6) vs. 1.3 (0.4, 2.3) ml/kg/min) and adiposity (−1.8 (−2.4, −1.1) vs. −0.8 (−1.5, -0.1)%), each p=0.04, and a large improvement in HDL-cholesterol (0.13 (0.075, 0.186) vs. -0.028 (−0.083, 0.023) mmol/l, p<0.0001). There was no group×time effect on other outcomes at 8 months, or on any outcomes at follow-up. The change in PWV at 8 months correlated with changes in insulin and insulin resistance (both r=0.32), diastolic BP (r=0.24), BMI (r=0.22) and adiposity (r=0.18).ConclusionsEight months of aerobic exercise training improved fitness, adiposity, and HDL-cholesterol levels, but did not reduce arterial stiffness in children with excess weight. PWV improved as a function of insulin resistance, BP, BMI and adiposity. Weight loss may be required to improve arterial stiffness. Exercise benefits waned after discontinuing the program.Trial RegistrationThis study is registered at www.clinicaltrials.gov NCT02383485.