We report the case of a half-marathon runner who presented with exertional heatstroke (EHS), whose management was confounded by concurrent treatment of his bipolar disorder with olanzapine. Antipsychotics can have a profound effect on thermoregulation and can cause athletes to present with features of neuroleptic malignant syndrome in the setting of EHS. It is vital for medical providers to consider the thermoregulatory effects of all medications, including antipsychotics, when providing care during sporting events.