Wong, S. H., Chan, C. O., & Chen, Y. J. (2005). Pre-exercise glycemic index meal: Effect on running performance when carbohydrate-electrolyte solution is consumed during exercise. Medicine and Science in Sports and Exercise, 37(5), Supplement abstract 1602.

Endurance-trained males (N = 9) completed three trials in random order separated by at least seven days. Each trial was a 21-km performance run on a level treadmill. The first five kilometers were run at 70% VO2max with the remainder run as fast as possible. The pre-run (two hours) meals were of a high glycemic index (GI = 83), a low glycemic index (GI = 36), or sugar-free. Immediately before and at every 2.5 km during each run, 2 ml/kg of body weight of 6.6% CHO-electrolyte solution was consumed.

There were no differences in time to complete the 21-km run or metabolic responses between the conditions.

Implication. When a large amount of CHO-electrolyte solution is consumed during an extended endurance run, performance and metabolic changes are independent of varied pre-exercise glycemic indexed foods.

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