The Modulation of Individual Level of Fatigue Through Placebo Effect in Obesity

Fatigue is a central symptom of obesity: it significantly impacts daily functioning, psychological well-being, compliance with physical therapy, and quality of life. However, the full understanding of the origin and treatment of fatigue in obesity is still a matter of debate, requiring further research, especially from new perspectives. From a neuroscientific perspective, fatigue is more than the subjective perception of tiredness resulting from mental or physical exertion or illness. It results in the complex interaction between (bottom-up) sensory input coming from the periphery, and motivational and psychological input, which is related to top-down cognition. In this framework, placebos may affect the output of the top-down cognitive processing by altering the individual evaluation of the ongoing peripheral performance. Indeed, evidence from both healthy conditions and clinical contexts suggests that fatigue can be modulated. The after-effect of such a modulation can be observed not only at a behavioural level, in terms of physical endurance, but also a psychological (i.e., decreased of perceived fatigue) and neurophysiological (changes in brain activity, especially in the fatigue-related components as the RP) levels.