Psychophysiological barriers to active mobility: effect of adiposity and effort perception on physical behaviour

The obesity epidemic sweeping the world represents a significant individual, social, and economic burden. The strong correlation between adiposity and poor physical activity levels is thought to be explained by a positive caloric imbalance. However, recent results from longitudinal studies show that weight gain significantly predicts physical activity levels, while sedentariness does not. The traditional idea of obesity growth does not, and cannot, justify this dynamic. Therefore, it is reasonable to hypothesise that the relationship between body composition and dynamic physical activity is at least bidirectional. Given these assumptions, in this thesis, factors of influence on physical activity and a proposed physiological mechanism by which adiposity may have a negative effect on physical activity levels are explored, and the statistical significance of the findings is tested on an Italian population sample. It is assumed that adiposity has an important positive effect on effort perception, and a secondary negative effect on intrinsic self-perception (e.g., a reduced sense of self-efficacy) so that by shifting motivational affectivity from intrinsic to extrinsic, its behavioural effectiveness is lost. In other words, weight gain precedes the decline in physical activity levels, and increased perceived exertion leads to reduced daily movement. Health recommendations are rooted in motivation, and this new perspective would explain their limited effectiveness in an adult environment despite the institutional investments.