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J Gerontol A Biol Sci Med Sci. 2018 May 10. doi: 10.1093/gerona/gly109. [Epub ahead of print]

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.

Author information

1
Sealy Center on Aging, University of Texas Medical Branch, Galveston, TX.
2
Office of Biostatistics, Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX.
3
Division of Rehabilitation Sciences, University of Texas Medical Branch, Galveston, TX.
4
Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX.
5
Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX.

Abstract

Background:

Essential amino acids (EAA) and aerobic exercise (AE) acutely and independently stimulate skeletal muscle protein anabolism in older adults.

Objective:

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.

Methods:

We phone screened 971, enrolled 109, and randomized 50 independent, low-active, non-frail, non-diabetic older adults (age 72±1 yrs). We used a 2x2 factorial design. The interventions were: daily nutritional supplementation (15 g EAA or placebo) and physical activity (supervised AE training three 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.

Results:

45 subjects completed the 24-week intervention. VO2peak and walking speed increased (p<0.05) in both AE groups, irrespective of supplementation type, but muscle strength increased only in the EAA+AE group (p<0.05). EAA supplementation acutely increased (p<0.05) 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.

Conclusions:

In non-frail, 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.

ClinicalTrials.gov Identifier:

NCT00872911.

PMID:
29750251
DOI:
10.1093/gerona/gly109

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