Hawley, J. A., Pedersen, D. J., Lessard, S. J., Coffey, V. G., Churchley, E. G., Wootton, A. M., Hg, T., & Watt, M. J. (2008). High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is co-ingested with caffeine. ACSM 55th Annual Meeting Indianapolis, Presentation Number, 669.

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This study determined the effects of the co-ingestion of caffeine with carbohydrate on rates of muscle glycogen resynthesis during recovery from exhaustive exercise. Trained subjects (N = 7) completed two experimental trials in a randomized, double-blind crossover design. The evening prior to an experiment, Ss performed intermittent exhaustive cycling and then consumed a low-carbohydrate meal. The following morning Ss rode until volitional fatigue. Upon completion, Ss consumed either carbohydrate or the same amount of carbohydrate plus caffeine during four hours of passive recovery. Muscle biopsies and blood samples were taken at regular intervals throughout recovery.

Muscle glycogen levels were similar at exhaustion and increased by a similar amount after one hour of recovery. After four hours of recovery, caffeine plus carbohydrate resulted in higher glycogen accumulation. The overall rate of resynthesis for the four-hour recovery period was 66% higher in caffeine plus carbohydrate group compared to the carbohydrate-only group. In the caffeine plus carbohydrate group, after one hour of recovery plasma caffeine levels increased to ~31 Mm and at the end of the recovery reached ~77 mM.

Implication. Post-exercise ingestion of caffeine with carbohydrate has an additive effect on rates on post-exercise muscle glycogen accumulation.

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