I know that one can easily burn-out by doing both "too much" and going "too fast" in their training (esp. when speedwork is involved). but what about JUST "too much"? I know you can definitely experience short term fatigue with doing too many easy miles (like a week or two), but is there a sense in which you can "deplete the system" (in a way similar to the way you can with anaerobic work) which results in a required long period of time off/reduced training?
I want to try a long, gradual build-up to high mileage without any speed-work (at first), but I don't want to fry myself if it doesn't seem to be working well. I want hope that I can just back the mileage down and feel good again.