AJP E-00110-2025 Supplemental Files

Resting and maximal exercise respiratory rates decline in aging, but the efficiency of muscular exercise is well maintained. We interrogated numerous structural and functional aspects of the mitochondrial reticulum using a standard mouse model of aging. We observed no age-associated changes in coupling efficiency of mitochondrial preparations, but respiratory control decreased and there were numerous subtle changes in mitochondrial morphology in aging mouse muscles. Overall mitochondrial functioning is well preserved in aging indicating the performance decrements are related to loss of muscle mass and cardiovascular function.