Every athlete will find a time when their body tells... no, DEMANDS that they back off on their training. If the athlete ignores their body's insistence this is when injury will rear its ugly head. For me, this happened about two weeks ago. I completed my second Tough Mudder, and this one was even more awesome and exciting than my last one. Something about that race just makes me so proud to be a Mudder.
Anyway, so I became a Mudder times 2 and felt great, wasn't too terribly sore, had enough sleep, life was good. The Monday after my Mudder I went to work and taught my class as per the usual, and was shocked to find myself exhausted after about 10 minutes. I'm not talking slight muscle fatigue, I'm talking legs are heavy, absolutely drained, gotta fight to finish the 45 minutes exhausted. After the class was over, the feeling didn't go away. It didn't matter what I ate, how much I slept, I was just physically done. Luckily, I connected this to my training (I had been trying to complete a running streak where you run a minimum of a mile daily as well as my twice weekly lifting, and my classes) This was my body's way of saying, "Hey! I need some rest! and not just one measley day!"
So I relinquished my tight chokehold on my schedule and backed off, teaching a bunch of classes from the floor and only doing my classes. It's been two weeks, and that mind-numbing tiredness is no longer lingering. This week I'm trickling in my lifting workouts again, and then next week I start up my running again. Hey, I've got a half marathon and a 10 miler to train for in October!
The body will let you know when it's had enough, it's important to listen to it and be smart about it. If you try and push through you may find yourself sidelined for months rather than a few days or weeks.