Association of exercise with appetite and energy intake through endocrine mechanism

Abstract

Appetite has been receiving extensive attention, lately, as a key factor for successful calorie restriction (CR) leading to the prevention of obesity and a slowdown of the aging process. A growing body of evidence has been accumulating, showing that endocrine networks mediate a complex interplay between the central nervous system and numerous organs involved in appetite and energy homeostasis. Gut hormones are known to play important roles in this mechanism. The hormone family is divided into two categories: orexigenic ghrelin and anorexic hormones, such as peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). These endocrine signals interact not only with the hypothalamus, but also with higher neural circuits including the prefrontal cortex and insula, suggesting tight linkages between peripheral and central appetite systems. An increase in physical activity combined with CR are recognized as measures for obesity prevention-sort of like 'two wheels of one cart'. However, the long-term efficacy of exercise-induced weight loss is generally lower than expected, mainly attributed to a compensatory increase in energy intake (EI) for the energy deficit produced by exercise. Recently, several reports on exercise of various intensities and duration have shown the potent physiological factors contributing to alterations in circulating levels of gut hormones and improved responses of satiety signals following meal intake. These studies prove the presence of 'crosstalk' between the 'two wheels' mediated by the neuro-endocrine axis. This paper aims to highlight the association of exercise with appetite and EI via the blood kinetics of gut hormones , and discusses future perspectives in this field.