Depression is a huge problem in nowadays society. Both young and old can suffer an overwhelming sense of helplessness and anxiety.
If you are a cynic you could say people just have too much time to worry. A remark that doesn’t help anybody, nor is it true in my opinion.
This article explains why exercise is a great way to beat depression. Other articles like Why you have to allow yourself to experience your emotions and Being grateful everyday pays off approach the subject from a different angle.