Effects of intense cycling training on plasma leptin and adiponectin and its relation to insulin resistance

Adiponectin, the most abundant protein secreted by white adipose tissue, is known for its involvement in insulin resistance (HOMA-R). The purpose of this investigation was to assess the effect of intense cycling training for six months on plasma concentrations of adiponectin and leptin and HOMA-R.

Eight trained males non professional cyclists participated in this study. They completed two times maximal exercises separated by six months heavy cycling training. Blood samples were obtained before exercise, at the end and after 30 and 60 minutes of recovery.

Before training, adiponectin concentrations were not significantly altered after maximal exercise, but plasma leptin levels decreased significantly at the end of exercise (-21.42%, p<0.01) and after 60 min of recovery (-21.18%, p<0.05). After 6 months training, subjects exhibited a decreased in control leptin concentrations (-44.91%, p<0.05) and in HOMA-R (-30.68%, p<0.05) and showed delayed increase in adiponectin concentrations (after 30 min of recovery) (14.10%, p<0.01).

Our results showed that adiponectin is sensitive to maximal exercise when realised after intense training and that six months heavy cycling training don't affect adiponectin concentrations, but decreases the synthesis of leptin and HOMA-R and improves aerobic capacity. Furthermore, it appears that after 6 months heavy chronic exercise adiponectin is not associated with aerobic capacity and/or insulin resistance and/or body composition modifications.