So, finally I got the time to read and write something about your post as well.

Excercise could help in the prevention of anxiety and depression, eventhough I found at least one study that stated the available data was inconclusive

The mechanisms behind physical exercise are quite complex and yet not fully understood. As far as I know, most of the available literature seem to indicate a positive correlation between prevention and/or treatment of at least affective disorders - although it cannot be said for sure, whether there is a causation or not.

But even if the correlation turns out not be be relevant at all - there are so many more already proven benefits of regular exercise, which should encourage everybody to workout constantly.

I think, some of the most prevalent diseases can be at least partly prevented with a healthy lifestyle, which is mainly a combination of strong mental resilience as well as a strong body.