Exercise and the regulation of energy intake

Energy balance is the resultant of ingested calories and energy expenditure and is generally maintained within narrow limits over prolonged periods. E xercise leads to an increase in energy expenditure which is, in the long-te rm, counteracted by increased energy intake. Evidence for this comes from a study in voluntarily running female rats that increased their daily food i ntake to 130% of the sedentary controls. In contrast, when considered on a short-term basis, exercise will suppress food intake to prevent a potential ly dangerous disruption of energy substrate homeostasis. Studies in permane ntly cannulated rats submitted to a test meal and 2 hrs swimming reveal tha t both food intake and exercise lead to increases in glucose and free fatty acid (FFA) levels in the blood. These changes in glucose and FFA, combined with the exercise-induced alteration in among others glucagon, corticotrop in releasing hormone (CRH) and body temperature, may lead to the short-term anorexic effect of exercise.