Title | Exercise, amino acids, and aging in the control of human muscle protein synthesis. |
Publication Type | Journal Article |
Year of Publication | 2011 |
Authors | Walker DK, Dickinson JM, Timmerman KL, Drummond MJ, Reidy PT, Fry CS, Gundermann DM, Rasmussen BB |
Journal | Med Sci Sports Exerc |
Volume | 43 |
Issue | 12 |
Pagination | 2249-58 |
Date Published | 2011 Dec |
ISSN | 1530-0315 |
Keywords | Aging, Amino Acids, Dietary Supplements, Exercise, Female, Humans, Male, Muscle Proteins, Muscle, Skeletal, Muscular Atrophy, TOR Serine-Threonine Kinases |
Abstract | In this review, we discuss recent research in the field of human skeletal muscle protein metabolism characterizing the acute regulation of mammalian target of rapamycin complex (mTORC) 1 signaling and muscle protein synthesis (MPS) by exercise, amino acid nutrition, and aging. Resistance exercise performed in the fasted state stimulates mixed MPS within 1 h after exercise, which can remain elevated for 48 h. We demonstrate that the activation of mTORC1 signaling (and subsequently enhanced translation initiation) is required for the contraction-induced increase in MPS. In comparison, low-intensity blood flow restriction (BFR) exercise stimulates MPS and mTORC1 signaling to an extent similar to traditional, high-intensity resistance exercise. We also show that mTORC1 signaling is required for the essential amino acid (EAA)-induced increase in MPS. Ingestion of EAAs (or protein) shortly after resistance exercise enhances MPS and mTORC1 signaling compared with resistance exercise or EAAs alone. In older adults, the ability of the skeletal muscle to respond to anabolic stimuli is impaired. For example, in response to an acute bout of resistance exercise, older adults are less able to activate mTORC1 or increase MPS during the first 24 h of postexercise recovery. However, BFR exercise can overcome this impairment. Aging is not associated with a reduced response to EAAs provided the EAA content is sufficient. Therefore, we propose that exercise combined with EAA should be effective not only in improving muscle repair and growth in response to training in athletes, but that strategies such as EAA combined with resistance exercise (or BFR exercise) may be very useful as a countermeasure for sarcopenia and other clinical conditions associated with muscle wasting. |
DOI | 10.1249/MSS.0b013e318223b037 |
Alternate Journal | Med Sci Sports Exerc |
PubMed ID | 21606874 |
PubMed Central ID | PMC3289515 |
Grant List | T32 HD007539 / HD / NICHD NIH HHS / United States 1UL1RR029876-01 / RR / NCRR NIH HHS / United States R01 AR049877-09 / AR / NIAMS NIH HHS / United States UL1 TR000071 / TR / NCATS NIH HHS / United States R01 AR049877 / AR / NIAMS NIH HHS / United States P30 AG024832-08 / AG / NIA NIH HHS / United States T32-HD07539 / HD / NICHD NIH HHS / United States P30 AG024832 / AG / NIA NIH HHS / United States T32 HD007539-11 / HD / NICHD NIH HHS / United States UL1 RR029876-01 / RR / NCRR NIH HHS / United States UL1 RR029876 / RR / NCRR NIH HHS / United States |