Impact of Aging and Lifelong Exercise Training on Mitochondrial Function and Network Connectivity in Human Skeletal Muscle.

This article investigates the effects of volume-dependent lifelong endurance exercise training on mitochondrial function and network connectivity in aging human skeletal muscle. The study found that healthy aging alone did not significantly impair mitochondrial content, function, or network structure, except for a decline in ADP sensitivity. However, older men engaging in high-volume lifelong endurance exercise exhibited increased mitochondrial oxidative capacity, greater mitochondrial volume and connectivity, and higher protein levels of ADP/ATP exchangers (ANT1 + 2 and VDAC1) and the antioxidant enzyme SOD2 compared to untrained or moderately trained peers. Additionally, mitochondrial reactive oxygen species (ROS) emission and markers of oxidative damage were not elevated with age or altered by exercise training. These findings suggest that high-volume endurance exercise may enhance mitochondrial quality and function in older adults, potentially contributing to improved muscle performance and metabolic health.