My roommate (a female) played D-1 hockey in college. About November of last year she collapsed in the morning and after some medical tests and about 3 weeks we landed on likely adrenal fatigue due to being in an over trained state.
This took her about 2.5 years to work into. She is a workout machine, and I can't handle half the volume she normally did. I mean like 2 sessions a day, every day, weights or run/swim/bike (she got into triathlons after college) in addition to walking biking or rollerblading everywhere since she had no car. And she only slept about 5 hours per day. This was after her time with hockey where she had 3 hours of ice time almost every day, and then since she is a bit crazy, her own weight sessions or other conditioning on top of team stuff. And she pushed it to near failure, 95%, whatever metric you want to use, constantly.
I tried to hang with her workouts and lasted about 10 days before I felt I was over reaching and needed a few days off with some good food and sleep. My point is, I have seen no one ever train as hard as her (she was in the US olympic hockey program from ages 10-19 when she blew out her knee) as regularly as her, and it still took her over two years to become "over trained." After this, it took about 3 months before she could do much more than use the elliptical lightly without feeling like she was going to pass out. Bending over made her dizzy, and just going to work took a toll. She is just now getting to a point where she can train with any intensity and regularity. (and much smarter regarding recovery now)
So I agree with Bone, TRY to over train, find your limits, and back off slightly. when you do get run down, don't be stubborn and continue to push through using whatever stimulants you can to get through the day. I saw first hand where that goes, and it isn't pleasant.
Sorry for the Double post. . .