I have often heard this. And even witnessed it some. But i wonder if the phenomenon is actually due to the fact that people who are in good health and well when

I have often heard this. And even witnessed it some. But i wonder if the phenomenon is actually due to the fact that people who are in good health and well when they retire are more likely to stay active and those who are not in good health or don't feel well, tend to not stay very busy after they no longer are required to.