When the author refers to "normal tired" and "dead tired", I think that echoes with my two states. I don't quite think of them as existing on a scale, but the experiences sound similar.
Doing stimulating things (exercise, reading aloud, singing) can usually bring me out of the state of languor. Just getting that adrenaline rush is enough to jolt me back to life (and thus I don't think of it as recharging; more like a jump start).
If I'm exhausted, I can feel gravity in my joints, and I'll have to rest. Regular sleep, exercises, and generally keeping a good health is the only way I can combat exhaustion.