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Age and aerobic exercise training effects on whole body and muscle protein metabolism.
Am J Physiol Endocrinol Metab. 2004 Jan; 286(1):E92-101.AJ

Abstract

Aging in humans is associated with loss of lean body mass, but the causes are incompletely defined. Lean tissue mass and function depend on continuous rebuilding of proteins. We tested the hypotheses that whole body and mixed muscle protein metabolism declines with age in men and women and that aerobic exercise training would partly reverse this decline. Seventy-eight healthy, previously untrained men and women aged 19-87 yr were studied before and after 4 mo of bicycle training (up to 45 min at 80% peak heart rate, 3-4 days/wk) or control (flexibility) activity. At the whole body level, protein breakdown (measured as [13C]leucine and [15N]phenylalanine flux), Leu oxidation, and protein synthesis (nonoxidative Leu disposal) declined with age at a rate of 4-5% per decade (P < 0.001). Fat-free mass was closely correlated with protein turnover and declined 3% per decade (P < 0.001), but even after covariate adjustment for fat-free mass, the decline in protein turnover with age remained significant. There were no differences between men and women after adjustment for fat-free mass. Mixed muscle protein synthesis also declined with age 3.5% per decade (P < 0.05). Exercise training improved aerobic capacity 9% overall (P < 0.01), and mixed muscle protein synthesis increased 22% (P < 0.05), with no effect of age on the training response for either variable. Fat-free mass, whole body protein turnover, and resting metabolic rate were unchanged by training. We conclude that rates of whole body and muscle protein metabolism decline with age in men and women, thus indicating that there is a progressive decline in the body's remodeling processes with aging. This study also demonstrates that aerobic exercise can enhance muscle protein synthesis irrespective of age.

Authors+Show Affiliations

Short KR
Endocrinology Research Unit, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Vittone JL
No affiliation info available
Bigelow ML
No affiliation info available
Proctor DN
No affiliation info available
Nair KS
No affiliation info available

MeSH

AdultAgedAgingBody CompositionEnergy MetabolismExerciseFemaleFollow-Up StudiesHumansLeucineMaleMiddle AgedMuscle ProteinsPhenylalanineProteinsRadioactive TracersReference Values

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

14506079

Citation

Short, Kevin R., et al. "Age and Aerobic Exercise Training Effects On Whole Body and Muscle Protein Metabolism." American Journal of Physiology. Endocrinology and Metabolism, vol. 286, no. 1, 2004, pp. E92-101.
Short KR, Vittone JL, Bigelow ML, et al. Age and aerobic exercise training effects on whole body and muscle protein metabolism. Am J Physiol Endocrinol Metab. 2004;286(1):E92-101.
Short, K. R., Vittone, J. L., Bigelow, M. L., Proctor, D. N., & Nair, K. S. (2004). Age and aerobic exercise training effects on whole body and muscle protein metabolism. American Journal of Physiology. Endocrinology and Metabolism, 286(1), E92-101.
Short KR, et al. Age and Aerobic Exercise Training Effects On Whole Body and Muscle Protein Metabolism. Am J Physiol Endocrinol Metab. 2004;286(1):E92-101. PubMed PMID: 14506079.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Age and aerobic exercise training effects on whole body and muscle protein metabolism. AU - Short,Kevin R, AU - Vittone,Janet L, AU - Bigelow,Maureen L, AU - Proctor,David N, AU - Nair,K Sreekumaran, Y1 - 2003/09/23/ PY - 2003/9/25/pubmed PY - 2004/2/13/medline PY - 2003/9/25/entrez SP - E92 EP - 101 JF - American journal of physiology. Endocrinology and metabolism JO - Am J Physiol Endocrinol Metab VL - 286 IS - 1 N2 - Aging in humans is associated with loss of lean body mass, but the causes are incompletely defined. Lean tissue mass and function depend on continuous rebuilding of proteins. We tested the hypotheses that whole body and mixed muscle protein metabolism declines with age in men and women and that aerobic exercise training would partly reverse this decline. Seventy-eight healthy, previously untrained men and women aged 19-87 yr were studied before and after 4 mo of bicycle training (up to 45 min at 80% peak heart rate, 3-4 days/wk) or control (flexibility) activity. At the whole body level, protein breakdown (measured as [13C]leucine and [15N]phenylalanine flux), Leu oxidation, and protein synthesis (nonoxidative Leu disposal) declined with age at a rate of 4-5% per decade (P < 0.001). Fat-free mass was closely correlated with protein turnover and declined 3% per decade (P < 0.001), but even after covariate adjustment for fat-free mass, the decline in protein turnover with age remained significant. There were no differences between men and women after adjustment for fat-free mass. Mixed muscle protein synthesis also declined with age 3.5% per decade (P < 0.05). Exercise training improved aerobic capacity 9% overall (P < 0.01), and mixed muscle protein synthesis increased 22% (P < 0.05), with no effect of age on the training response for either variable. Fat-free mass, whole body protein turnover, and resting metabolic rate were unchanged by training. We conclude that rates of whole body and muscle protein metabolism decline with age in men and women, thus indicating that there is a progressive decline in the body's remodeling processes with aging. This study also demonstrates that aerobic exercise can enhance muscle protein synthesis irrespective of age. SN - 0193-1849 UR - https://www.unboundmedicine.com/medline/citation/14506079/Age_and_aerobic_exercise_training_effects_on_whole_body_and_muscle_protein_metabolism_ DB - PRIME DP - Unbound Medicine ER -