[nmdeadhead]

I get the runner's high most days when I run (and I typically run 6 or 7 days a week), starting about a half hour in. I feel very comfortable physically and mildly euphoric mentally. I hear more in the music I'm listening to than I normally do and I tend to feel very good about people (both others and myself).

FWIW, I do most (80%?) of my running at a 130bpm heart-rate and typically don't get the runner's high when I'm working out more intensely (the other ~20% of the time).

I don't know that I would run as much as I do if I didn't get the runner's high, although I didn't get it regularly when I began. One big takeaway I got from reading one of Lydiard's books was that when you're building your base you basically can't run too slowly, but it's very easy to run too quickly.

If you run too quickly you risk injury and burn-out which interferes much more with making progress as a runner than if perhaps you're not running quite fast enough to get the maximum adaptation for your effort.