Taylor D J, Kemp G J, Thompson C H, Radda G K
MRC Biochemical and Clinical Magnetic Resonance Unit, Oxford Radcliffe Hospital, UK.
Mol Cell Biochem. 1997 Sep;174(1-2):321-4.
31P magnetic resonance spectroscopy studies were carried out on calf muscle of 144 normal male and female subjects age 20-83 years in order to investigate age-related changes in muscle metabolism. Compared to the young adults (20-29 years), oxidative capacity was higher in the children (6-12 years) and was significantly decreased in the elderly (70-83 years). In the adults, the intracellular pH change during exercise diminished with increasing age, resulting in higher calculated free [ADP] and possibly serving as an adaptive mechanism to stimulate mitochondrial ATP production. Children also had higher pH and [ADP] in exercise, but unlike results from the elderly, this was associated with higher oxidative capacity and more rapid metabolic recovery from exercise.
