Previous research has shown that dance class and rehearsal stress different cardiorespiratory energy systems than dance performance. The aim of the present study was to monitor the physiological parameters of a number of dancers during a 12-week rehearsal period and an 8-week performance schedule. Seventeen dancers (8 men and 9 women) from 2 companies undertook the multistage dance specific aerobic fitness test before the rehearsal period, before the performance period, and after the performance period. Heart rate data were collected throughout the test; the mean heart rate during stage 5 and blood lactate levels were measured at the end of the test. No significant changes in heart rate or lactate parameters were noted between the prerehearsal and preperformance tests, but significant decreases during the preperformance and postperformance tests were shown in both parameters (p < 0.01 and p < 0.01, respectively), which suggests an increase in the subjects' aerobic capacities during the performance period. Implications from the present study suggest that dancers are not adequately physiologically prepared to perform to the same degree to which their skills are honed. The study suggests that supplemental training is required to bridge this physical gap and better prepare the dancer for performance.