Metabolic Response to Carbohydrate Ingestion During Exercise in Males and Females

American Journal of Physiology-Endocrinology and Metabolism. 2006;290(4):E708-E715

To increase understanding of optimal carbohydrate ingestion before/during intense exercise and to investigate potential gender differences in fuel utilization, three studies in 18-25 year-old endurance trained athletes were conducted to perturb exogenous carbohydrate utilization (oxidation). Carbohydrate load was manipulated by molecular weight (to understand gastric emptying’s role) and by changing substrate. These studies increased knowledge in understanding the factors that limit the carbohydrate supply from exogenous sources, could assist in development of optimal drinks for carbohydrate delivery during exercise, and could help formulate specific guidelines for females.

Findings

• There was no difference in exogenous or endogenous carbohydrate oxidation in men who consumed a high or low molecular weight gluclose polymer solution during 150 min of cycling at 50% W.
• Oxidation of combined ingestion of maltodextrin and fructose was greater than maltodextrin alone. It is likely that this is due to stimulation of multple transport mechanisms which increase CHO availability for oxidation.
• There were no gender differences in systemic glucose turnover during exercise with or without carbohydrate ingestion.

Access the full-text publication here.