Yeah it's a pretty amazing feeling. Makes you feel glad to be alive, like you can conquer the world. Although, to be honest, I wouldn't mind trading the occasional high for the ability to run 3000 miles in a year - that's some serious stamina.

I've seen others commenting that they think runner's high is akin to a state of flow - it's not. I flow occasionally when I play tennis and write, and it's a completely different feeling - one of non-feeling, simply being and doing which allows me to lose my ego for a short while. I'm acutely aware of myself, my body, and my senses when I feel the runner's high.