Possible association of exercise with appetite and motivation to eat

Appetite is a key factor for adjustment or disruption of energy balance（ EB） in modern society. Contrary to expectation, energy expenditure（ EE） caused by exercise does not increase the feeling of hunger or subsequent energy intake（ EI）, resulting in negative EB. The gut hormone family, known to play important roles in appetite regulation, is divided into 2 categories; orexigenic ghrelin and anorexigenic hormones, such as glucagon-like peptide-1（ GLP-1） and peptide YY （PYY）, all of which are released from the gastrointestinal tract in response to nutritional conditions. Recent findings have suggested that both single bouts of exercise and repeated habitual exercise modify the plasma levels of gut hormones related to appetite decrease. Appetite is regulated not only by the hypothalamus and brainstem, which receive neural and humoral signals arising peripherally from gastrointestinal organs and adipose tissues, such as the vagal nerves, leptin, and gut hormones, but also by higher brain centers, in which sensory, reward, and cognitive factors are involved. Most importantly, appetitive motivation generates real action, resulting in individual eating behavior. This review aims to highlight changes in appetite and EI caused by various types of exercise, the physiological characteristics and actions of various gut hormone family members, as well as the association of exercise with blood kinetics of the gut hormone family and its relevance in regulation of appetite and EB. In addition, future perspectives regarding this field of research are discussed