Acute physical effort enhances interoceptive accuracy without improving error awareness: evidence from the Heart Rate Discrimination Task

According to Fechner’s law, perceived sensations increase logarithmically with stimulus intensity. In the context of exercise, rising physical effort is therefore accompanied by increasingly salient bodily signals such as heart rate. Interoception, the sensing of internal bodily states, supports adaptive responses to these changing demands, for instance, by guiding the regulation of exertion. Beyond physical regulation, interoceptive signals have also been proposed to inform higher-order monitoring processes, such as error detection. Yet it remains unclear whether acute exercise sharpens cardiac interoception and whether enhanced access to bodily signals translates into greater awareness of errors. In a within-subject design, 36 healthy adults completed two tasks while cycling at low versus moderate intensity: a Heart Rate Discrimination Task assessing cardiac interoceptive accuracy and insight, and a Go/No-Go task measuring error awareness through post-error reports. Moderate effort selectively improved interoceptive accuracy (threshold closer to true heart rate), without changes in precision of lapse rate. Physical effort also made participants more confident in their interoceptive judgments, but this confidence increase was unrelated to actual accuracy. In the Go/No-Go task, commission errors were more frequent during cycling, yet the proportion of consciously detected errors was unaffected. Interoceptive performance did not reliably predict error awareness. These results indicate that acute exercise recalibrates cardiac interoception, likely by enhancing the salience of afferent signals, but does not strengthen higher-order monitoring of action. Error-related cardiac responses may thus reflect affective or orienting processes rather than a causal basis for awareness.