Iwashita, S., King, D., Baier, S., & Flakoll, P. J. (2006). Glutamine supplementation enhances energy expenditure but not performance during exercise. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 2254.

This study investigated whether glutamine ingestion before the exercise increases the energy expenditure and exercise performance. Thirty minutes before starting cycle exercise, healthy adults (M = 6: F = 4) consumed supplementation mixed with non-calorie flavored water twice, either a glutamine or isocaloric gluconeogenic amino acid mixture control. Exercise testing was separated into two periods: 30-minutes of fixed exercise (~70% VO2peak), and a time trial in which Ss accumulated, as quickly as possible, the work output of the first period. Six days separated the treatment and control conditions.

During fixed exercise, energy expenditure was higher in the glutamine condition than in the control. Time to accumulate a set amount of work, respiratory exchange ratio, and Rating of Perceived Exertion were not different between groups.

Implication. Glutamine has a potential to enhance energy expenditure during exercise, but the higher expenditure was not associated with an improvement in performance.

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