This is fascinating:
If borne out raises the question of whether a brief (what duration would need exploring) nap helps, whether meditation helps, or stimulants like coffee, help reduce the glutamates. There are anecdotal reasons to think they may. Also interesting that such fatigue can be compensated by people through willpower (presumably to a greater or lesser extent) and whether that's a good thing for a person's health or bad thing for a person's health (and then short term or long term).