Psychobiology of Perceived Effort During Physical Tasks

Perception of effort is the conscious sensation of the effort exerted during a physical task, and it is one of the subjective experiences that accompany voluntary actions. Perception of effort has an important role in the self-regulation of behavior. In physical tasks requiring endurance, perception of effort is one of the main determinants of pacing and performance and it is one of the barriers that prevent sedentary individuals from adopting an active lifestyle. Furthermore, high perception of effort is one of the main features of the disabling fatigue affecting patients with cancer and other medical conditions. The afferent feedback model postulates that perception of effort arises from sensory signals produced by peripheral receptors (e.g., group III–IV afferents). According to the corollary discharge model, perception of effort arises from corollary discharges of the central motor command to the working muscles (including the respiratory muscles). Current electrophysiological evidence, showing that motor-related brain activity correlates with perception of effort, corroborates the corollary discharge model of perception of effort. Preliminary evidence from neuroimaging studies suggests that the cingulate and insular cortices, and possibly the thalamus and precuneus, are brain areas that might be involved in perception of effort. Future research should focus on targets for interventions aimed at reducing perception of effort. Such interventions might benefit athletes involved in endurance performance, patients suffering from fatigue, and sedentary individuals wishing to adopt a more active lifestyle.