Hey Nick - in 2008, I reached that dangerous zone where I was running ~50mpw and getting faster. I deluded myself into thinking that I was fitter than I was and started ramping up the training. I bought Pfitzinger's "Advanced Marathoning" and stuck to the 55mpw once through (at paces that were too high for me at that point and I was already feeling the effects but was in denial). And then did the 70mpw plan right after, but extended the long runs and was doing closer to 80mpw.
The high mileage wasn't the problem in itself, though. Pfitzinger's plans include a lot of "quality" work - mile repeats, intervals, etc., higher-paced stuff which sends the pulse (in a non-advanced, less-fit runner who thinks he's superman) soaring. And not enough recovery time (for me).
So, I was running when I should have been recovering. And not only running, I was running
hard. And getting faster, for sure. My HM time dropped to 1:29 and was shooting for a 3:12 marathon -
ridiculous numbers for someone like me!
Anyway, that's what I did. And it got to the point where I couldn't even stand up from the couch without my HR jumping into race mode. I basically stopped sleeping nights and just crashed at random times during the day. I didn't have a resting pulse anymore becuase I never actually rested. That's overtraining. It sounds like such a timid condition that you just have to take a little time off to set right, but you actually re-program your sympathetic vegetative nervous system (in English it's the
autonomic nervous system), you end up in permanent "survival mode", what the metabolism does when the cave bear is after you - doesn't let you rest. Ever. Till you die.
You end up depressed/bi-polar, and just generally unhappy with everything. Some people contract serious diseases like pneumonia when they're overtrained. I just felt all tensed-up, luckily.
And I'm fine now, generally healthy as can be. Except my resting pulse hovers around the 55 mark and I feel the effects of any higher-pulse workouts for a few days. And I'd just like to get back to 'normal'
(sorry for writing the first chapter of a book, but you asked lol)