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J Gerontol A Biol Sci Med Sci. 2015 Nov;70(11):1379-85. doi: 10.1093/gerona/glu134. Epub 2014 Aug 28.

Skeletal Muscle Mitochondrial Function and Fatigability in Older Adults.

Author information

1
Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
2
Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania. glynnn@edc.pitt.edu.
3
Translational Center for Metabolic Imaging, University of Washington, Seattle.
4
Division of Endocrinology and Metabolism, School of Medicine, University of Pittsburgh, Pennsylvania.
5
Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.
6
Translational Gerontology Branch, National Institute on Aging, Baltimore, Maryland.
7
Division of Endocrinology and Metabolism, School of Medicine, University of Pittsburgh, Pennsylvania. Department of Health and Physical Activity, School of Education, University of Pittsburgh, Pennsylvania. Present address: Florida Hospital-Sanford|Burnham Translational Research Institute for Metabolism and Diabetes, Orlando.
8
Division of Endocrinology and Metabolism, School of Medicine, University of Pittsburgh, Pennsylvania. Present address: Florida Hospital-Sanford|Burnham Translational Research Institute for Metabolism and Diabetes, Orlando.

Abstract

BACKGROUND:

Fatigability increases while the capacity for mitochondrial energy production tends to decrease significantly with age. Thus, diminished mitochondrial function may contribute to higher levels of fatigability in older adults.

METHODS:

The relationship between fatigability and skeletal muscle mitochondrial function was examined in 30 participants aged 78.5 ± 5.0 years (47% female, 93% white), with a body mass index of 25.9 ± 2.7 kg/m(2) and usual gait-speed of 1.2 ± 0.2 m/s. Fatigability was defined using rating of perceived exertion (6-20 point Borg scale) after a 5-minute treadmill walk at 0.72 m/s. Phosphocreatine recovery in the quadriceps was measured using (31)P magnetic resonance spectroscopy and images of the quadriceps were captured to calculate quadriceps volume. ATPmax (mM ATP/s) and oxidative capacity of the quadriceps (ATPmax·Quadriceps volume) were calculated. Peak aerobic capacity (VO2peak) was measured using a modified Balke protocol.

RESULTS:

ATPmax·Quadriceps volume was associated with VO2peak and was 162.61mM ATP·mL/s lower (p = .03) in those with high (rating of perceived exertion ≥10) versus low (rating of perceived exertion ≤9) fatigability. Participants with high fatigability required a significantly higher proportion of VO2peak to walk at 0.72 m/s compared with those with low fatigability (58.7 ± 19.4% vs 44.9 ± 13.2%, p < .05). After adjustment for age and sex, higher ATPmax was associated with lower odds of having high fatigability (odds ratio: 0.34, 95% CI: 0.11-1.01, p = .05).

CONCLUSIONS:

Lower capacity for oxidative phosphorylation in the quadriceps, perhaps by contributing to lower VO2peak, is associated with higher fatigability in older adults.

KEYWORDS:

Aerobic capacity; Fatigability; Mitochondrial function; Skeletal muscle.

PMID:
25167867
PMCID:
PMC4612379
DOI:
10.1093/gerona/glu134
[Indexed for MEDLINE]
Free PMC Article

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