As I age, I've learned to distinguish "not being excited" (languor) and "being tired" (exhaustion), which to my younger self felt like the same thing. The former is not always caused by a lack of energy, but also excessive idleness, especially if I'm doing things that requires attention but also isn't intellectually stimulating.<p>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.<p>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).<p>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.