Trommelen, J., Holwerda, A. M., Kouw, I. W., Halson, S. L., Verdijk, L. B., van Loon, L. J. (2016). Protein ingestion before sleep provides precursors for post-exercise overnight de novo muscle protein synthesis. Medicine & Science in Sports & Exercise, 48(5), Supplement abstract number 88.

This study determined the impact of ingesting 30 g casein protein with and without 2 g free leucine prior to sleep on myofibrillar protein synthesis rates during post-exercise overnight recovery. Healthy young males performed a single bout of resistance-type exercise in the evening (7:45 PM) after a full day of dietary standardization. Ss were provided with adequate recovery nutrition (20 g protein + 45 g carbohydrate) immediately after exercise (8:45 PM). Thirty minutes prior to sleep (11:30 PM), Ss were divided into three groups and ingested a beverage containing 30 g intrinsically L-[1-13C]-phenylalanine-labeled protein with (protein plus leucine, N = 12) or without (protein only, N = 12) 2 g free leucine or a noncaloric placebo (N = 12). Continuous intravenous L-[ring-2H5]-phenylalanine, L-[1-13C]- leucine and L-[ring-2H2]-tyrosine infusions were applied. Blood and muscle tissue samples were collected to assess whole-body protein balance, myofibrillar protein synthesis rates, and overnight incorporation of dietary protein-derived amino acids into de novo muscle protein.

Protein ingestion prior to sleep improved overnight whole-body net protein balance with leucine added the most effective. Both protein groups were significantly higher than placebo. Myofibrillar protein synthesis rates did not differ between the three groups. Myofibrillar L-[1-13C]-phenylalanine enrichments increased following protein ingestion and did not differ between the protein treatments.

Implication. "Protein ingestion prior to sleep supports overnight recovery by providing precursors for de novo muscle protein synthesis during sleep. However, the ingestion of 30 g of casein protein with or without additional free leucine does not increase muscle protein synthesis rates during post-exercise overnight recovery."

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