We have previously shown that protein ingestion before sleep increases overnight muscle protein synthesis rates. Whether prior exercise further augments the muscle protein synthetic response to presleep protein ingestion remains to be established.
This study aimed to assess whether resistance-type exercise performed in the evening increases the overnight muscle protein synthetic response to presleep protein ingestion.
Twenty-four healthy young men were randomly assigned to ingest 30 g intrinsically L-[1-13C]-phenylalanine and L-[1-13C]-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-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 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%·h−1 ± 0.002%·h−1 vs. 0.040%·h−1 ± 0.003%·h−1, P < 0.001, based on L-[ring- 2 H5]-phenylalanine) and 31% (0.073%·h−1 ± 0.004%·h−1 vs. 0.055%·h−1 ± 0.006%·h−1, P = 0.024, based on L-[1-13C]-leucine) higher in PRO + EX compared with PRO. Substantially more of the dietary protein-derived amino acids were incorporated into de novo myofibrillar protein during overnight sleep in PRO + EX compared with PRO (0.026 ± 0.003 vs. 0.015 ± 0.003 molar percent excess, P = 0.012).
Resistance-type exercise performed in the evening augments the overnight muscle protein synthetic response to presleep protein ingestion and allows more of the ingested protein-derived amino acids to be used for de novo myofibrillar protein synthesis during overnight sleep.
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1NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, THE NETHERLANDS; 2Top Institute Food and Nutrition (TIFN), Wageningen, THE NETHERLANDS; 3AIS Physiology, Australian Institute of Sport, Belconnen, AUSTRALIA; and 4Gatorade Sports Science Institute, Leicester, UNITED KINGDOM
Address for correspondence: Luc J. C. van Loon, Ph.D., Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, P.O. Box 616, 6200 MD Maastricht, The Netherlands; E-mail: L.vanLoon@maastrichtuniversity.nl.
Submitted for publication April 2016.
Accepted for publication June 2016.
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