The process of running have many systems of the body involved to do the exercise, being the three main ones the muscular system (related to moving the body running), circulatory system (circulation of the body and disbridution of oxygen and others molecules importants to maintain the body while running), and respiratory system (breathing), there is also the nervous system and skeletal during the exercise. They work together because the nervous system receive the stimulus, making the respiratory, muscular, skeletal and circulatory systems put more force for increase oxygen uptake, increase in speed the gas exchange in muscle tissues, and direct the energy for the muscles that are in activity.