Utter, A. C., Kang, J., Robertson, R. J., Nieman, D. C., Chaloupka, E., Suminski, R. R., Piccinni, C. R., Teles, A. L., & Davis, J. M. (2002). The effect of carbohydrate ingestion on ratings of perceived exertion during a competitive marathon. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 948.

Marathoners received carbohydrate (N = 48) or placebo (N = 50) beverages at the rate of one liter per hour during a race. Every 3.2 km, heart rate and a rating of perceived exertion were measured.

Heart rate was lower in the placebo group, particularly during the final 10 km of the race. There were no differences in RPE between the groups throughout the race. Post-race plasma glucose, insulin, and lactate levels were significantly lower and cortisol and growth hormone were significantly higher in the placebo group. The carbohydrate group ran at a higher intensity than the placebo group.

Implication. Carbohydrate ingestion was related to higher intensity marathon performance while there was no difference in perceived exertion when compared to a placebo group.

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