Leptin and adiponectin represent two newly discovered adipose tissue derived hormones; that are both associated with health status and glucose and free fatty acid (FFA) metabolism. Moreover, acute and chronic exercises affect body composition, carbohydrate and lipid metabolism. It is thus interesting to evaluate the effects of physical exercise and training on leptin and adiponectin levels. It seems that leptin concentration is not modified after short-term exercise (<60 min) or exercise that generates an energy expenditure lower than 800 kcal. Leptin levels decrease after long-term exercise (> or =60 min) stimulating FFA release, or after exercise that generates energy expenditure higher than 800 kcal. Adiponectin concentration presents a delayed increase (30 min) after short-term intense exercise (<60 min) performed by trained athletes. For adiponectin, limited data suggest that adiponectin concentration presents a delayed increase (30 min) after short-term intense exercise (<60 min) performed by trained athletes. It seems that adiponectin concentrations do not change in response to long-term exercise (> or =60 min). Short-term training (<12 weeks) and long-term training (> or =12 weeks) show contrasting results regarding leptin and adiponectin. Most training studies which improve fitness levels and affect body composition could decrease leptin and increase adiponectin concentrations.