The optimal exercise modality for the improvement of health-related parameters and microvascular function in obese adolescents is not yet fully understood. Therefore, this study aimed to 1) compare the microvascular phenotype of obese and normal-weight adolescents; and 2) to determine the effects of a lifestyle intervention including three months of moderate continuous training (MCT) or high-intensity interval training (HIIT) on health-related parameters and microvascular function in 29 obese adolescents. Body composition, metabolic profile, aerobic fitness and cutaneous blood flow, measured using laser Doppler flowmetry at rest and during post-occlusive reactive hyperemia, were assessed prior to and following lifestyle intervention. Sixteen normal-weight adolescents were included as reference controls for baseline microvascular parameters. At baseline, obese adolescents had higher peak blood flow, peak vascular conductance and area under the curve for post-occlusive reactive hyperemia than normal-weight adolescents. Conversely, peak blood flow, peak vascular conductance and area under the curve data remained unchanged after MCT and HIIT without intergroup differences. However, the peak/basal blood flow ratio decreased in both MCT and HIIT groups without any interaction between groups due to basal CBF increase (tendency p=0.074). Exercise training, whatever the modality, does not improve peak microcirculatory function.

No abstract

Obesity is associated with vitamin D (VD) deficiency and arterial stiffness. This randomized control trial assessed the effects of VD supplementation during a weight-loss program on carotid intima-media thickness (IMT) and carotid compliance in obese adolescents. Participants were randomly assigned to receive either a 12-week lifestyle program with VD supplementation (n = 13), a lifestyle program without VD supplementation (n = 13) or a control group composed of normal-weight adolescents (n = 18). Serum total and free 25-hydroxyvitamin D (25(OH)D), IMT and carotid compliance were measured before and after the trial. Insufficiency in 25(OH)D concentration was found in 73% of obese participants compared to 22% among controls. Obese adolescents had lower free 25(OH)D and displayed higher IMT but lower carotid compliance than controls. Free 25(OH)D and IMT were negatively correlated in adolescents displaying VD insufficiency at baseline. After three months, total and free 25(OH)D increased in both groups. The changes of IMT and carotid compliance were similar between groups. The changes in IMT were correlated with the changes in total 25(OH)D in obese adolescents with VD insufficiency at baseline (r = −0.59, p = 0.03). While the lifestyle program with VD supplementation did not affect carotid compliance, IMT reduction was improved in obese adolescents.

No abstract

No abstract