The immediate adaptations to aerobic exercise of the cardiovascular function of overweight/obese pre-pubertal children

OBJECTIVE To investigate the immediate adaptations to aerobic exercise of the cardiovascular function of overweight/obese pre-pubertal children. METHOD The study group consisted of 54 healthy volunteer Cypriot children, aged 11.2 +/- 0.5 years, divided according to the IOTF criteria into normal-weight (n=21) and overweight/obese (n=33) subgroups. Measurements were made of their anthropometric characteristics [ body mass index (BMI), height, skinfold thickness, and waist, abdominal and hip circumference], and blood pressure and heart rate: (a) At rest, (b) during treadmill exercise at 4 km/h, 5.6 km/h and 8 km/h of 10 min duration at each stage, and (c) at the 3rd min of recovery. In addition, during the last 10 sec of each stage, ratings of perceived exertion (RPE) were obtained using the Children's OMNI Scale (category range, 0-10). Pulse pressure, mean arterial pressure, double product, stroke volume, cardiac output, peripheral resistance and cardiac index were determined using specific equations. RESULTS The normal-weight children had better values of systolic blood pressure (p<0.01), mean blood pressure (p<0.01), resting pulse pressure (p<0.05), heart rate (p<0.05), double product (p<0.001) and cardiac index (p<0.01) than the overweight/obese children. In addition, the normal-weight children showed a better response in the cardiac index at rest (p<0.05) and at 8 km/h (p<0.01), and at the 3rd min of recovery (p<0.01) than the overweight/obese children. Significant correlation was demonstrated between RPE and BMI (r=0.422, p<0.001), body fat (r=0.375, p<0.01), waist circumference (r=0.344, p<0.05), abdominal circumference (r=0.376, p<0.001), systolic blood pressure (r=0.279, p<0.05), double product (r=0.301, p<0.05), cardiac index (r=-0.331, p<0,05) and exercise time on the treadmill (r=0.487, p<0.001). CONCLUSIONS Overweight/obese children showed poorer cardiovascular function and higher ratings of perceived exertion than normal-weight children, due to their poor level of physical fitness.