Glutamine is a naturally non-essential neutral amino acid that helps with the transport of nitrogen between tissues. Heavy exercise has shown a reduction of glutamine in the blood (31). The amount of glutamine in the muscle is known to be related to the rate of protein synthesis (32) and glycogen synthesis (33) in the first few hours of recovery period of exercise.
31 – Parry-Billings, M., Budgett, R., Koutedakis, Y., Blomstrand, E., Brooks, S.., Williams, C., & Newsholme, E. A. (1992). Plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. Medicine and science in sports and exercise, 24(12), 1353-1358.
32 – Rennie, M. J., Edwards, R. H. T., Krywawych, S., Davies, C. T., Halliday, D., Waterlow, J. C., & Millward, D. J. (1981). Effect of exercise on protein turnover in man. Clin Sci, 61(5), 627-639.
33 – Bowtell, J. L., Gelly, K., Jackman, M. L., Patel, A., Simeoni, M., & Rennie, M. J. (1999). Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. Journal of Applied Physiology, 86(6), 1770-1777.