Voluntary Aerobic Exercise Attenuates Frailty in a Sex-Specific Manner in Older Male and Female C67Bl/6 Mice

Abstract

Aerobic exercise is thought to improve overall health and reduce frailty, but whether this is beneficial in both sexes is unclear. We introduced voluntary wheel running to older (~22 months) male and female mice to see if it reduced frailty. While frailty declined in both, mortality was not affected. Exercise did reduce signs of sarcopenia, where exercised females lost fat and gained lean tissue, while males lost total tissue weight; these effects were graded by activity. Exercise protected the heart against age-related declines in systolic and diastolic function, but only in male hearts. Exercise also prevented the age-related dysregulation of the immune system, measured as serum cytokines, but in only females. Aerobic exercise improved the overall health of mice even when introduced late in life, but the mechanisms involved are sex specific.