Objectives Obesity, oxidative stress, inflammation, and endothelial dysfunction often occur in concert, and there is evidence to suggest that oxidative stress and inflammation may promote development of endothelial dysfunction in obesity. It has been shown that the link between obesity and cardiovascular disease may be mediated through oxidative, inflammatory stress and endothelial dysfunction. Therefore, the purpose of this study was to investigate the effect of physical exercise on vascular endothelial function, oxidative and inflammatory stress in obese children and adolescent for investigates the impossible mechanisms of exercise improving cardiovascular function.
Methods 26 male obese adolescents (years: 13.77 ± 1.89; BMI: 30.05 ± 2.75) to take a 6-weeks exercise intervention. Obesity was defined according to the international age-related cut-off points for childhood obesity. 10 lean control subjects were also recruited to allow cross-sectional comparison, were studied only at baseline. Both the subjects and their legal guardian were informed about the procedure, nature and purpose of this study. Informed consent was obtained from all the adolescents and/or their legal guardian before the initial exercise training for the adolescents to participate was voluntary. All subjects had not participated in a weight loss program at least 8 months before the project. Exclusion criteria were any medication, heart disease, diabetes, renal disease, smoking, regular physical exercise. All obese subjects participated in an exercise training program at a closed weight loss camp for 6 weeks. The exercise program was supervised by two professional trainers. This program consisted of aerobic exercise and resistance exercise. The aerobic exercise program include basketball, swimming, jogging and other games, which was maintained at 60% to 70% of maximum HR for about 1 h, and was performed 5 sessions a week. Each session lasted 80 minutes and included the following procedure: 15 minutes of warm-up, 50 minutes of physical training, and 15 minutes of cool down. The resistance exercise program consisted of flexion and extension for shoulder, elbow, hip, knee and trunk muscle groups, which was performed 3 times a week (3 sets a time, 10 repetitions a set) at an intensity of approximately 65% to 70% of pre-training maximum strength. The diet-related lifestyle changes were not monitored the flow mediate dilation (FMD) was detected using ultrasound technique in before and after exercise intervention, while the serum levels of MDA, 8-isoprostane, CRP and TNF-α was testing.
Results the weight, percentage of body fat, insulin resistance shown a significant decline after 6 weeks of exercise intervention (P < 0.01), and FMD (8.34 ± 1.36% vs 12.57 ± 2.56%, P <0.05) was improved significantly, the serum MDA (5.38 ± 1.03 mmol/L vs 2.18 ± 1.43 mmol/L, P < 0.01), 8-isoprostane (36.35 ± 7.57 pg/ml vs 25.57 ± 6.54 pg/ml, P < 0.05), CRP (4.17 ± 0.85 mg/L vs 2.66 ± 0.81 mg/L, P < 0.05) and TNF-α (33.82 ± 10.43 pg/ml vs 20.87 ± 9.16 pg/ml, P< 0.05) levels significantly decreased.
Conclusions Exercise can improve body composition, insulin resistance, dyslipidemia, vascular endothelial function, oxidative stress and inflammation in obese adolescents; the mechanisms exercise improved endothelial function may be associated with the anti-oxidative stress and anti-inflammation in obese adolescents. This work was supported by funds (nos. AGA10177 and 10YJA880127).