Joining a book club, church or sports group linked to longer life after retirement

One of the most troubling findings about aging has to do with what happens to your health after you retire. While some people find that their bodies and minds thrive in the absence of the stress of work, some 10 to 25 percent experience a significant drop in their health and well-being.

In trying to explain the different health trajectories of retirees, scientists are increasingly focusing on social factors. The theory is that social engagement or isolation can affect a person's cognitive functioning and happiness, which in turn can affect their overall health.