Reality: Inactivity is /as strongly correlated with/ being unhealthy as smoking is.<p>Unhealthy people, naturally, don't feel happy, energetic, and in general up for going outside pretty much of the time, and as such are less active. You can take any handful of unhealthy people and they are likely to be relatively sedentary compared to healthy folks, but they're probably all unhealthy for different reasons.<p>Same with the "sitting will kill you" articles that pop up every now and then. The causality is there, it's just being drawn in the wrong direction.