A dopamine/noradrenaline reuptake inhibitor improves performance in the heat, but only at the maximum therapeutic dose

A maximal dose of bupropion has enabled subjects to maintain a higher power output than reported during the placebo session in the heat. Because this drug is taken in different doses it is important to know if there is a doseresponse relationship with regard to exercise at high ambient temperature. Ten well-trained male cyclists ingested placebo (pla; 200?mg) or bupropion (50%, 75%, 100% of maximal dose: bup50: 150?mg; bup75: 225?mg; bup100: 300?mg) the evening before and morning of the experimental trial. Trials were conducted in 30?degrees C (humidity 48%). Subjects cycled for 60?min at 55% W max, immediately followed by a time trial to measure performance. Bup100 improved performance (pla: 33'42?+/-?2'06; bup100: 32'06?+/-?1'54; P?=?0.035). Bupropion increased core temperature at the end of exercise, while heart rate was higher only in the bup100 trial (P?