Serial response to auditory stimuli administered during dynamic physical exercise of the steady-state and non-steady-state exhaustive nature was investigated in 61 athletes. Similarly to previous studies with serial visual stimuli, auditory reaction time was found to depend on the exercise load and grew in parallel to it. The latency increase followed the character of the imposed exercise, too. In the slope of the latency increase individual and group differences were noted that, at least in part, could be explained by the existing differences in physical fitness plus motivation. Overall mean of linear correlation was 0.61 between the latency of auditory reaction and steady-state work output and 0.47 for the non-steady-state all-out efforts in our material. Reaction time tended to increase also when the effort though being constant was subjectively exhaustive during the studied duration (r = 0.46). As shown by the results, the decisive factor in this was not so much the absolute severity of work, but rather subjective fitness level. Despite that the data throughout the study were modeled by fitting a linear model, the conclusions are not contradictory to Duffy's inverted U-shape activation theory if understood in Gutin's interpretation.