[conistonwater]

Just to be clear: if running is "intense exercise" that means you're doing it wrong, and you will have a much better time of it if you slow down to easy conversational pace. (People usually use the run-walk method to develop such a pace in the beginning.) The thing about exercise and human biology is that there is some room for subjective statements, but not that much room. I, for one, find it quite pleasant about exercise that it doesn't matter how it makes me feel temporarily, that it works so long as I do the right thing.