This is a physiological question that maybe doesn't have an answer -- or the answer is totally individual. But I thought I'd ask anyway and get some perspectives.
Anyway: This morning I ran 45 minutes, and I know it was about 4 miles total. While my tank wasn't empty, I was pretty close to it. Which got me to thinking -- is there a predictable relationship between energy, pace, and distance? In other words, if I'd gone a bit slower, could I have:
* Ran longer before hitting the same low energy level, maybe hitting the same distance but of course taking more time;
* Ran faster and maybe covered more distance but not run for quite as long;
What I think I'm getting at is, is there an optimal strategy for increasing distance related to pace? Does any of this make sense lol?