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Abstract

Mitochondria are believed to be involved in human ageing. Whilst it is clear that various mitochondrial DNA mutations do accumulate in human tissues with age, whether or not they interfere with respiratory chain function is uncertain. We question the results of previous studies which have measured respiratory chain function in human skeletal muscle with age. Whilst cytochrome c oxidase deficient fibres are a real finding in skeletal muscle, the contribution of mitochondrial DNA mutations to human ageing is still controversial. Our results show for mitochondria to be involved in ageing then it must be through a more subtle mechanism than a global decline in respiratory chain function.

Mitochondria: Dynamic Organelles in Disease, Aging, and Development

“…Although these studies show that aging is associated with declining respiratory function, accumulation of variable levels of mtDNA deletions and point mutations, and accumulation of oxidative damage to mtDNA, there remain substantial concerns about whether these changes are causal in the aging process. First, some studies suggest that the respiratory decline in old individuals is largely due to physical inactivity, rather than chronological age (Brierley et al, 1997). Second, the functional significance of the mtDNA alterations is unclear.…”

The Muscle-Brain Axis and Neurodegenerative Diseases: The Key Role of Mitochondria in Exercise-Induced Neuroprotection

“…Muscle mitochondrial ATP production has been shown to decrease by around 8% per 10 years of higher age in a population of 146 healthy men and women of ages between 18 and 89 years [ 80 ]. This deterioration of mitochondrial function was attributed mainly to physical inactivity [ 81 ], suggesting that regular exercise may at least partially prevent the aging-related decline of mitochondrial function. While acute exercise induces the formation of ROS, with oxidative damage occurring more frequently during high intensity bouts [ 82 ], regular moderate exercise reduces oxidative stress by bolstering the antioxidant defences of muscle tissue [ 30 , 83 , 84 , 85 ].…”