Objectives: We sought to characterize the impact of obesity on vascular function in adolescents and to determine whether an exercise program reverses abnormalities in endothelial function.
Background: Obesity, a major modifiable risk factor for cardiovascular disease, is epidemic in Western societies, with rapid rates of increase in the young. Atherosclerosis begins in childhood, and endothelial dysfunction is its earliest detectable manifestation.
Methods: The influence of eight weeks of circuit training (CT) was examined in 19 obese subjects (14.3 +/- 1.5 years), using a randomized, crossover protocol. Functional capacity and muscular strength were assessed by standard techniques. Body composition was examined using anthropometric measures and dual-energy X-ray absorptiometry. Conduit vessel endothelial function was assessed using high-resolution ultrasound and flow-mediated dilation (FMD) of the brachial artery.
Results: Circuit training decreased abdominal and trunk fat and significantly improved fitness and muscular strength (p < 0.05). In the obese group, FMD was significantly impaired relative to control subjects (n = 20) at entry (5.3 +/- 0.9% vs. 8.9 +/- 1.5%, p < 0.05) and was normalized after CT (8.8 +/- 0.8%, p < 0.05).
Conclusions: Circuit training improved functional capacity, muscular strength, and body composition in obese adolescents. Furthermore, conduit vessel function was normalized after exercise training. If vascular dysfunction is an integral component of the pathogenesis of vascular disease, this study supports the value of an exercise program in the management of obese adolescents.