Same word as overexert:

bankrupt, burn out, conk out, cripple, debilitate, disable, do in, drain, draw, enervate, enfeeble, fag, fatigue, frazzle, impoverish, overdo, overexert, overextend, overfatigue, overtire, overwork, peter out, poop, poop out, prostrate, run ragged, sap, suck dry, tucker, use up, weaken, wear down, weary