The contribution of the peripheral chemoreflex to the ventilatory response to exercise and aerobic exercise capacity remains incompletely understood. Low-dose dopamine has been reported to specifically inhibit the peripheral chemoreceptors. We therefore investigated the effects of intravenous dopamine (3 microg kg(-1)min(-1)) on cardiopulmonary exercise test (CPET) variables in 13 healthy young male subjects. The study was prospective, placebo-controlled, and randomized with more than 24h between placebo and dopamine administrations. During the CPET, dopamine decreased the .V(E)/.V(CO2) output slope (24.61+/-1.84 vs. 23.09+/-1.81, placebo vs. Dopamine respectively, p=0.025), without affecting maximum workload, .V(E) and O(2) uptake. In conclusion, our study reveals that inhibition of peripheral chemoreflex function with dopamine decreases the .V(E)/.V(CO2) slope during dynamic exercise, with no change in aerobic exercise capacity.