Mitochondrial Dysfunction

In Brief Innovative noninvasive methods open a new window on the cell in vivo. This window reveals that the tempo of mitochondrial dysfunction with age varies among muscles and in proportion to Type II muscle fiber content. Exercise training can reverse age-related dysfunction, thereby providing an intervention to slow the pace of aging and disability in the elderly. New, non-invasive methods applied in vivo reveal that mitochondrial dysfunction in human muscle with age is reversible with exercise training.