Ali., A., Moss, C., Yoo, J. Y., & Breier, B. (2012). Effect of carbohydrate mouth rinse and/or ingestion on high-intensity exercise performance. Presentation 2352 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This study examined the effects of fluid intake, a carbohydrate mouth-rinse, and carbohydrate ingestion on cycling performance under glycogen-compromised conditions. Recreationally trained cyclists (N = 9) participated in four main trials. Activity was performed on an electronically-braked cycle ergometer, with each trial separated by seven days and taking place over two days. On Day 1, Ss underwent a 90-minute glycogen-reducing exercise protocol, immediately followed by a low-carbohydrate meal and then a subsequent overnight fast. The following morning a 1-hour time-trial performance was conducted. Ss performed a certain amount of work as fast as possible for the performance test. For the main trials, Ss a) mouth-rinsed with a 15% carbohydrate solution, b) ingested a 7.5% carbohydrate solution, c) mouth rinsed with a taste-matched placebo, or d) ingested a taste-matched placebo. Solutions were administered every 12.5% of exercise completed. Blood samples were taken every 25% of exercise.

There were no significant differences in performance time between treatments. However, mean power output was higher in ingested carbohydrate condition relative to other trials. There was a main effect of treatment and interaction of treatment x time for plasma glucose, Values were similar at the start of exercise but were higher in ingested-carbohydrate trial and 100% of exercise relative to other trials. There were treatment and interaction effects for insulin. Levels were higher in the ingested-carbohydrate trial between 50-100% of exercise relative to other trials.

Implication. Mouth-rinsing with a carbohydrate solution in a glycogen-compromised condition did not affect exercise performance. Carbohydrate ingestion increased glucose concentrations and improved performance relative to fluid ingestion and carbohydrate mouth-rinse trials.

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