When you take part in regular running your body should experience the following:
Oxygen-rich blood travels through a vast network of tiny capillaries, which allow the exchange of gases, nutrients and waste products. Once the blood arrives at the muscles, it picks up the oxygen, offloads some carbon dioxide and it makes its way back to the heart. Muscle cells don’t, however, take all the oxygen that the blood is carrying. Regular running increases the ability of the muscles to extract more oxygen by triggering the growth of additional capillaries in the muscle. Therefore running is good for you because it improves blood supply.