Kerr, K. L., Bishop, P., Pritchett, R., Kovacs, M., Davis, J. K., Casaru, C., & Green, M. (2008). Effects of pre-exercise nutrient timing on glucose responses and intermittent exercise performance. ACSM 55th Annual Meeting Indianapolis. Presentation number 849.

This study evaluated the effects of two pre-exercise feeding schedules (15 and 60 minutes) of a mixed-nutrient nutritional bar, on blood glucose levels and subsequent intermittent high-intensity exercise performance. Moderately trained athletes (N = 10) completed a 50-minute counterbalanced treatment, intermittent-exercise protocol. During one trial, Ss consumed 400 ml of water and a standardized nutritional bar 15 minutes before the exercise session. During another trial, Ss consumed 400 ml of water and a standardized nutritional bar 60 minutes before the exercise session. During another trial (control), Ss consumed only 400 ml of water.

There were no significant differences in plasma glucose response at rest, or during exercise among the three treatments. There were no significant differences in mean power between the three conditions. Pre-exercise nutrient feedings at 15 or 60 minutes before exercise did not affect intermittent cycling performance or blood glucose.

Implication. The timing of ingestion of a complex carbohydrate bar and water has no impact on performance.

Return to Table of Contents for this issue.