In summary, our results are in line with those of previous studies showing that prolonged moderateintensity exercise induces inspiratory muscle fatigue. They also provide a new insight into the recovery of this fatigue over 24 h. Furthermore, the present study is the first to document leg and breathing effort perception during such prolonged exercise. Thus we are able to suggest that the relative intensity of inspiratory muscle work during exercise (as indicated by the change in breathing effort) makes some contribution to leg fatigue, possibly via the activation of the inspiratory muscle metaboreflex.