That's why I advocate for elliptical machines if someone really wants to "run." Running isn't bad for you if you're wear proper shoes, have good form / posture, and run on soft ground. But many people don't do those and end up increasing their life expectancy but with terrible joints. Elliptical machines solve the issue by forcing your body to actually run properly but they eliminate the shocks that come with each step. And you're right - swimming is by far the best cardio anyone can do. Plus everyone needs to learn how to swim.

Sadly I can't do either for now, but hoping to by next Spring.