Q: Is Running Bad for You?

A: No.

(As always, we invite more nuanced discussion and commentary in the comments section.  I, for one, am very interested in the following part:

The issue here, as pointed out in an excellent special report by Alex Hutchinson published this month in Runner's World, is what happens long term to your heart if you are a pretty serious runner, averaging 20 or more miles a week consistently for a long time.

I'm having an unusually hard time finding that particular report--I'm also at work--but nevertheless, I'm wondering about what would constitute a "long time."  Also, as the rest of Gleiser's article points out, the body has a way of indicating instances of overuse.  At worst, those indications are injuries. I've run over twenty miles a week for a "long time," but I haven't done so uninterrupted because of the usual intermittent injuries.  How do those natural interruptions factor into all of this?  Again, discuss!)