The study started with around 1,000 people over the age of 50. Half of the participants were members of a runner’s club, and the other half were otherwise healthy people from Stanford, but not members of the running club.
However, we found that over time, the runners group had very low levels of disability that increased very slowly. The controls, on the other hand, had disability that increased much more quickly. At the end of the study, the difference between the disability levels was very dramatic.
Participants who were part of a runner’s club also enjoyed lower mortality rates — about half that of the non-participants. So not only were they less disabled, but they lived longer as well.