This year a study came out suggesting that, even better than antidepressant medication, exercise is the best way to stay mentally healthy. This is awesome. The thing about medication, of course, is there are always side effects, and they are always negative side effects. The opposite is true of exercise. Running can help keep one's mood elevated and, of course, side effects include better circulation, stronger muscles and denser bones, slower aging, maintaining a healthy weight, and the list goes on.
I found this article online last night when I was searching for more evidence of running as a natural way to prevent depression -- and it's just amazing. Daniele Seiss writes about her experiences with major depression and how long, long walks and then long runs helped her to beat the blues (and even the need to take antidepressant medication). She doesn't even fear another relapse because she's exercises to stay healthy and happy.
How cool is that? Yet another reason to make sure to stick to a running schedule.