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- Title
Effect of Aerobic Exercise Training and Essential Amino Acid Supplementation for 24 Weeks on Physical Function, Body Composition, and Muscle Metabolism in Healthy, Independent Older Adults: A Randomized Clinical Trial.
- Authors
Markofski, Melissa M; Jennings, Kristofer; Timmerman, Kyle L; Dickinson, Jared M; Fry, Christopher S; Borack, Michael S; Reidy, Paul T; Deer, Rachel R; Randolph, Amanda; Rasmussen, Blake B; Volpi, Elena
- Abstract
<bold>Background: </bold>Essential amino acids (EAA) and aerobic exercise (AE) acutely and independently stimulate skeletal muscle protein anabolism in older adults.<bold>Objective: </bold>In this Phase 1, double-blind, placebo-controlled, randomized clinical trial, we determined if chronic EAA supplementation, AE training, or a combination of the two interventions could improve muscle mass and function by stimulating muscle protein synthesis.<bold>Methods: </bold>We phone-screened 971, enrolled 109, and randomized 50 independent, low-active, nonfrail, and nondiabetic older adults (age 72 ± 1 years). We used a 2 × 2 factorial design. The interventions were: daily nutritional supplementation (15 g EAA or placebo) and physical activity (supervised AE training 3 days/week or monitored habitual activity) for 24 weeks. Muscle strength, physical function, body composition, and muscle protein synthesis were measured before and after the 24-week intervention.<bold>Results: </bold>Forty-five subjects completed the 24-week intervention. VO2peak and walking speed increased (p < .05) in both AE groups, irrespective of supplementation type, but muscle strength increased only in the EAA + AE group (p < .05). EAA supplementation acutely increased (p < .05) muscle protein synthesis from basal both before and after the intervention, with a larger increase in the EAA + AE group after the intervention. Total and regional lean body mass did not change significantly with any intervention.<bold>Conclusions: </bold>In nonfrail, independent, healthy older adults AE training increased walking speed and aerobic fitness, and, when combined with EAA supplementation, it also increased muscle strength and EAA-stimulated muscle protein synthesis. These increases occurred without improvements in muscle mass.
- Subjects
BODY composition; ESSENTIAL amino acids; MUSCLE metabolism; AEROBIC exercises; OLDER people; ANAEROBIC capacity
- Publication
Journals of Gerontology Series A: Biological Sciences & Medical Sciences, 2019, Vol 74, Issue 10, p1598
- ISSN
1079-5006
- Publication type
journal article
- DOI
10.1093/gerona/gly109