Physiological responses during cycle ergometry at a constant perception of effort

13 subjects performed an incremental test to exhaustion, 4,8-min submaximal rides, and a 1-h ride at the rating of perceived exertion (RPE) that corresponded to the physical working capacity at the OMNI threshold (PWC_OMNI) to examine: 1) the oxygen consumption (VO₂), heart rate (HR), minute ventilation (+V_E), respiratory frequency (FR), and power output responses during 1-h work bouts at a constant RPE that corresponded to the PWC_OMNI; and 2) the ability of current models to explain the responses for physiological and perceptual parameters during the 1-h work bouts. The RPE that corresponded to the PWC_OMNI represented a sustainable exercise intensity (56±5% (VO_2Peak) within the moderate-intensity domain. The mean, normalized slope coefficients for the VO₂, +V_E, and power output vs. time relationships during the 1-h rides were significantly less than zero. The mean, normalized slope coefficient for the FR vs.time relationship during the 1-h rides, however, was not significantly different from zero. Thus, RPE most clearly tracked FR responses during the 1-h rides. It was hypothesized that afferent feedback from respiratory muscles may have mediated the perception of effort during cycle ergometry at a constant RPE in the moderate-intensity domain.