OBJECTIVE Recent research has reported an improvement in exercise capacity following a series of acupuncture treatments. We examined the immediate effects of a single acupuncture treatment on perceived exertion and physiological responses during submaximal dynamic exercise, and maximal exercise capacity in human subjects. METHODS Ten healthy subjects (5 men, 5 women) participated in the study. After demonstrating consistency in using the rating of perceived exertion (RPE) scale, each subject underwent graded continuous maximal exercise testing on a cycle ergometer after genuine acupuncture, sham acupuncture, and rest without needles being inserted. Treatment conditions were randomized for each subject, and tests were conducted at least 72 hours apart. Heart rate and oxygen uptake were measured, and RPE was requested during the last 30 seconds of each 3-minute exercise stage. Data were analyzed with repeated-measures analysis of variance. RESULTS There were no statistically significant differences among conditions for RPE, oxygen uptake, heart rate, respiratory exchange ratio, ventilation, and ventilatory equivalent for oxygen at submaximal workloads. In addition, none of the physiological measures at peak exertion or the duration of exercise differed among conditions. CONCLUSIONS A single acupuncture treatment has no significant immediate effect on the perceived exertion and physiological responses during submaximal dynamic exercise or upon maximal exercise capacity among healthy individuals.