We have previously shown that protein ingestion prior to sleep increases overnight muscle protein synthesis rates. Whether prior exercise further augments the muscle protein synthetic response to pre-sleep protein ingestion remains to be established.
To assess whether resistance-type exercise performed in the evening increases the overnight muscle protein synthetic response to pre-sleep protein ingestion.
Twenty four healthy young men were randomly assigned to ingest 30 g intrinsically L-[1-C]-phenylalanine and L-[1-C]-leucine labeled casein protein before going to sleep with (PRO+EX: n=12) or without (PRO: n=12) prior resistance-type exercise performed in the evening. Continuous intravenous L-[ring-H5]-phenylalanine, L-[1-C]-leucine and L-[ring-H2]-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 myofibrillar protein.
A total of 57±1% of the ingested protein-derived phenylalanine appeared in the circulation during overnight sleep. Overnight myofibrillar protein synthesis rates were 37% (0.055±0.002 vs 0.040±0.003 %[BULLET OPERATOR]h, P<0.001; based upon L-[ring-H5]-phenylalanine) and 31% (0.073±0.004 vs 0.055±0.006 %[BULLET OPERATOR]h, P=0.024; based upon L-[1-C]-leucine) higher in PRO+EX compared to PRO. Substantially more of the dietary protein-derived amino acids were incorporated into de novo myofibrillar protein during overnight sleep in PRO+EX compared to PRO (0.026±0.003 vs 0.015±0.003 MPE, P=0.012).
Resistance-type exercise performed in the evening augments the overnight muscle protein synthetic response to pre-sleep protein ingestion and allows more of the ingested protein-derived amino acids to be used for de novo myofibrillar protein synthesis during overnight sleep.''
Med Sci Sports Exerc. 2016 Sep 16. Resistance Exercise Augments Postprandial Overnight Muscle Protein Synthesis Rates.