Hemodynamic Responses to Exercise in Obese Children and Adolescents before and after Overweight Reduction

OBJECTIVE: To determine the change of hemodynamic parameters in graded bicycle exercise testing in obese children before and after overweight reduction. METHODS: Forty-two obese children (mean age 11 years) and 40 healthy, lean children underwent graded bicycle exercise testing (1, 1.5, 2, 2.5 Watt/kg) recording the heart rate (HR) and blood pressure (BP) before exercise (T1), at maximum load (T2), and 6 min after ending the exercise (T3). Furthermore, the increase of the patient's heart rate within each ramp (I-HR) and the individual maximum load (Watt/kg) were recorded. After participating in an one-year outpa-tient intervention program for obese children, the study group underwent exercise testing again. Furthermore, we analyzed the lipid and insulin levels in the study group before and after overweight reduction and correlated the changes of the hemodynamic parameters to the changes of the insulin and lipid levels. RESULTS: The obese children had significantly (p<0.05) higher systolic blood pressure values at T1, T2, and T3 as compared to the lean children. The I-HR was significantly (p<0.05) higher in the study group. HR and BP at T1, T2, and T3, and the lipid and insulin values improved significantly in the study group after overweight reduction. The changes of HR and BP did not correlate to the changes of insulin and lipids. CONCLUSION: Compared to lean children, obese children demonstrated a significantly lower exercise capacity of the cardiovascular system, which improved after participating in an obesity intervention program. Overweight reduction influences the hemodynamic and metabolic changes of childhood obesity positively and thereby leads to an improvement of the cardiovascular risk factor profile.