Dr. Aaron S. Kelly, from the St. Paul Heart Clinic in Minnesota, and colleagues studied 20 children with a mean body mass index of 30.4. At baseline, a significant correlation was seen between levels of C-reactive protein and with fasting insulin. The children were randomized to a stationary cycling or to a non-exercising control group.

Compared with controls, exercising subjects showed a significant improvement in aerobic fitness, as measured by peak oxygen uptake. In addition, exercising subjects experienced a significant increase in HDL cholesterol levels and in brachial artery flow-mediated dilation, an indicator of endothelial function.