Perceptual cues in regulation of exercise intensity

Abstract

Regulation of exercise intensity is a pervasive characteristic of all endurance physical activities. While monitoring of exercise intensity is commonly based on physiological responses, majority of individuals regulate daily physical activities based on perceptual sensations generated by the body. Such perceptual sensations play a key role in regulation of exercise as they served as a protective mechanism to ensure that individuals exercise in a manner that does not disrupt their physiological homeostasis. Despite regulation of exercise intensity being a complex interaction between different perceptual sensations, there is a dearth of studies that examined multiple perceptual responses during exercise. With the aim to better understand perceptual cues in regulation of exercise intensity, three experimental studies were conducted to 1) examine the differentiation between mental effort and physical exertion during exercise, 2) examine the effects of mental fatigue on perception of exercise intensity, and 3) the roles of mental effort, physical exertion and affect in regulation of prescribed and preferred intensity exercise.<br><br>In order to distinguish between mental effort and physical exertion during exercise, this thesis developed two separate rating scales via three-step processes: 1) determining appropriate verbal descriptors (Study 1), 2) examining the response categorisation functioning (Study 2), and 3) establishing concurrent and construct validity of the rating scales (Study 3). Although mental effort and physical exertion were found to be closely associated, individuals were able to distinguish between the two responses across various exercise intensity levels. Such findings suggest that mental effort and physical exertion are two distinct perceptual cues.<br><br>Perception of exercise intensity was demonstrated to be negatively affected by non-physiological influences such as mental fatigue (Study 2). Both active and inactive young adults perceived greater physical exertion under mental fatigue albeit similar physiological responses. However, exercise performance was unaffected despite the increased physical exertion among participants.<br><br>Different perceptual cues were found to play different roles in regulation of exercise intensity (Study 3). Both mental effort and physical exertion were found to be more dominant than affective responses when regulating prescribed intensity levels. On the other hand, affect was found to be the dominant perceptual cue in regulating preferred intensity exercise. In addition, findings of present thesis suggest that affective responses were associated with the negative pacing profile exhibited by the participants.<br><br>The findings from this thesis have contributed several practical implications. First, it is recommended that exercise intensity prescription should not be based solely on physiological responses. Instead, perceptual cues account for individual differences as well as effects of non-physiological factors such as mental fatigue. Second, since different perceptual cues play different roles in regulation of exercise intensity, it is important to monitor multiple perceptual responses during exercise. The developed mental effort and physical exertion rating scales are valid tools to differentiate between the two perceptual responses during exercise. Third, it is important to pay attention to affective responses during exercise as individuals pace themselves during exercise based on that.