Metabolic effects of exercise in adolescent obesity

The rise in obesity related morbidity in children and adolescents requires urgent interventions to prevent and delay obesity and its co-morbidity. This thesis focused on exercise programs as a tool to counteract the metabolic effects of obesity in the adolescent population. The main objective was to determine in depth, the metabolic effects of a strictly controlled aerobic and resistance exercise program, respectively, (without additional dietary and lifestyle advice and weight loss). The intensity of the programs was designed to accommodate sedentary adolescents. Each program had a duration of 12 wks. The aerobic exercise program consisted of 48 sessions; 4x30 min/wk at ≥ 70% of VO2peak. The resistance exercise program consisted of 24 sessions; 2 x 1 h/wk; exercising all major muscle groups. Obesity related morbidity is strongly linked to excess body fat. Particularly specific body fat depots (abdominal, hepatic and intramyocellular fat) are thought to play a metabolically important role. High hepatic fat accumulation (non alcoholic fatty liver) is a highly prevalent disease in obese adolescents that can progress to liver inflammation, fibrosis and cirrhosis. Currently, only limited data are available on the effects of exercise on abdominal, hepatic and intramyocellular fat content.