Survival curves of cohorts of sedentary (n = 72) and spontaneous wheel-running mice (n = 72). The Kaplan-Meier representation of the two groups is shown. The median lifespan of the sedentary group was 750 days and it was 770 days in the wheel-runners. Maximal lifespan in both groups was 950 days. The functional tests were performed at different survival time points (3, 17, 20, 23, 26, and 29 months old) as shown by arrows in the longevity curve.