Influence of carbohydrate supplementation during resistance training on concentrations of the hormones cortisol and insulin

This study analysed the influence of maltodextrin ingestion before and during a single bout of resistance exercise on muscle damage and catabolic/anabolic hormone responses. Seven young men previously trained in resistance exercises performed two sessions each comprising ten exercises for the upper limbs, accompanied by ingestion of a solution containing 8% carbohydrate or placebo. Blood samples were obtained before and after training for analysis of insulin, cortisol and creatine kinase, and during the training period (after the second, fourth, sixth, eighth and tenth exercise) for glucose analysis. At all time-points, glucose was found to be significantly higher following ingestion of carbohydrate. Although the training led to an increase in cortisol, no differences were noted between the carbohydrate and placebo sessions. However, the levels of insulin after training were approximately three times higher following ingestion of carbohydrate (28.7 ± 3 ??U/ml) than following ingestion of placebo (9.5 ± 2.2 ??U/ml, p <0.05. We conclude that carbohydrate ingestion before and during resistance exercises does not affect catabolic activity, but provides an important anabolic muscle stimulus.