Re: too much running vs too much weights...whats worse???
I did a brief google search on this not long ago. Although the statement of "BPM above 130 burning muscle" seems a bit too vague and simplistic, there seems to be some relation between this frequency and using up glycogen stores, which affects muscle growth.
I'm no expert on this topic, nor do I care to read up on it any further, but I think there's a tiny shred of truth to it, although loosely misrepresented by such a simplistic statement.
If I recall correctly, my conclusion was, I had no reason to worry unless I was a serious bodybuilder (how's that for simplistic?).
If anyone cares to research it further, there are other sources on the web (aside from bodybuilding.com) that will explain it better.