Skeletal muscle mitochondrial function and lean body mass in healthy exercising elderly.
BACKGROUND
The decline in muscle mass (sarcopenia) with aging may be related to a decline in mitochondrial function. However, investigators have yet to reach a consensus as to whether a decline in mitochondrial function can be attenuated by physical activity has yet to reach a consensus.


METHODS
Using dynamic 31PMRS to measure mitochondrial function, we measured baseline Phosphocreatine (PCr), inorganic phosphate (Pi), phosphodiester (PDE), [ADP], pH and recovery times (t(1/2)) for PCr and [ADP] following exercise, in 45 older (73+/-4 years, SD), and 20 younger subjects (25+/-4 years, SD) who were matched for body mass across high and low activity levels and within age and sex groupings.


RESULTS
Baseline PCr, and Pi, were lower, and PDE higher in the older subjects compared to younger subjects (all P<0.01). The t(1/2)(ADP) was longer in older subjects (P<0.001) controlling for age and sex in the low activity group (P=0.02). In the older low activity groups, t(1/2)(PCr) was longer than high activity groups. Higher PDE levels were positively correlated with longer t(1/2)(PCr) in the older low activity females (both P<0.05).


CONCLUSIONS
Our data suggests that mitochondrial function declines with age in healthy, exercising elderly adults and that the decline appears to be influenced by the level of physical activity.
Waters
Debra L
DL
Department of Internal Medicine, University of New Mexico School of Medicine, 2701 Frontier Pl NE Surge Bldg. Rm 215, Albuquerque, NM 87131, USA. dwaters@salud.umn.edu
Brooks
William M
WM
Qualls
Clifford R
CR
Baumgartner
Richard N
RN
D000244:Adenosine Diphosphate / Q000378:metabolism; D000368:Aged; D000465:Algorithms; D001823:Body Composition / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008931:Mitochondria, Muscle / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010725:Phosphocreatine / Q000378:metabolism; D012727:Sex Characteristics
D010725:Phosphocreatine; D000244:Adenosine Diphosphate