Few people realize that a) burn-out has a high probability of recidivism; b) it changes the body, too. You develop a plethora of new nerve endings that fire discomfort and pain and that take years to diminish once you’ve made it through the acute phase.
You totally, literally become crippled by the system, and some people set themselves up for it willingly, kamikaze-style, thereby raising the bar for all others as well.