Poster Presenter

Laboratoire des adaptations cardio-circulatoires, respiratoires, métaboliques et hormonales à l'exercice musculaire
Omar Ben Ounis Omar B. Ounis, Mohamed Elloumi, Hassane Zouhal, Gérard Lac, Mohamed Amri, Zouhair Tabka
Tunisia

Objectives: Obesity is a significant public health issue in the world, and children and adolescents have not eluded this emerging epidemic. Recent evidence indicates that skeletal muscle is involved in the development of obesity. The purpose of this study was to characterize the cortisol, growth hormone (GH) and substrate profiles of obese children before and after individualized training program.

Methods: Twenty obese children (13.1 ± 0.8 yrs), 12 subjects (6 boys and 6 girls; 31.1 ± 1.1 kg/m2, VO2peak 1.92 ± 0.16 l/min) participated in two-month program of physical endurance and 10 subjects (5 boys and 5 girls; 30.9 ± 1.7 kg/m2, VO2peak 1.98 ± 0.12 l/min) served like control group. Training was individualized at the point were fat oxidation was maximal (Lipoxmax). Substrate oxidation was evaluated by indirect calorimetry. To determine plasma cortisol and GH concentrations blood was collected at rest before and after training program.

Results: Before the program, no significant differences were detected between training and control groups for any of the measured anthropometric, metabolic and hormonal variables. At the end of the two-month program, children of training group showed an increase in VO2peak and fat oxidation during exercise. After the program, baseline GH and cortisol levels increased significantly in training group (+ 0.9 ± 0.3 ng/mL and + 55.4 ± 10.3 ng/mL respectively, p < 0.01). Over the two-month period there was no change in any other variables measured, in control group.

Conclusions: Obese children demonstrated a clear shift fat oxidation during exercise and increased GH and cortisol levels after individualized exercise training program targeted at Lipoxmax.