We aimed to investigate the influence of interoceptive accuracy on affective valence, arousal, and ratings of perceived exertion (RPE) during 20 minutes of aerobic exercise at both moderate and heavy intensity among physically inactive men. We divided our participant sample into men with poor heartbeat perception (PHP, n = 13) and good heartbeat perception (GHP, n = 15), based on their cardioceptive accuracy. We measured their heart rate reserve (%HRreserve), perceived affective valence (Feeling Scale; +5/-5), perceived arousal (Felt Arousal Scale, 0-6), and ratings of perceived effort (RPE; Borg scale 6-20) every five minutes during an exercise session on a bicycle ergometer. During moderate-intensity aerobic exercise, the GHP group presented a greater decline in affective valence (p = 0.010; d = 1.06) and a greater increase in RPE (p = 0.004; d = 1.20) compared to the PHP group, with no group differences in %HRreserve (p = 0.590) and arousal (p = 0.629). Psychophysiological and physiological responses to the heavy-intensity aerobic exercise were not different between groups. We concluded that the influence of interoceptive accuracy on psychophysiological responses during submaximal fixed-intensity aerobic exercise was intensity-dependent in these physically inactive men