Santanasto 2014 J Gerontol A Biol Sci Med Sci
|Santanasto AJ, Glynn NW, Jubrias SA, Conley KE, Boudreau RM, Amati F, Mackey DC, Simonsick EM, Strotmeyer ES, Coen PM, Goodpaster BH, Newman AB (2014) Skeletal muscle mitochondrial function and fatigability in older adults. J Gerontol A Biol Sci Med Sci 70:1379-85.|
Abstract: 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.
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/m2 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 31P magnetic resonance spectroscopy and images of the quadriceps were captured to calculate quadriceps volume. ATPmax (mMATP/s) and oxidative capacity of the quadriceps (ATPmax·Quadriceps volume) were calculated. Peak aerobic capacity (VO2 peak) was measured using a modified Balke protocol.
ATPmax·Quadriceps volume was associated with VO2 peak and was 162.61 mM 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 VO2 peak 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).
Lower capacity for oxidative phosphorylation in the quadriceps, perhaps by contributing to lower VO2 peak, is associated with higher fatigability in older adults.
Labels: MiParea: Respiration, Patients Pathology: Aging;senescence
Organism: Human Tissue;cell: Skeletal muscle