Fill your lungs.

It's the power of exercise, via the heart-lung action, that then spurs the circulation of immune cells. Exercise trains your heart and lungs to pump oxygen- rich blood more efficiently and, by extension, send more immune cells into active duty. Your lungs move oxygenrich blood to the heart via capillaries, and then your heart extracts oxygen from the blood and pumps it around your body, like to the muscles you're contracting as you walk or cycle or squat, says Benjamin Levine, M.D., an exercise science professor at University of Texas Southwestern Medical Center in Dallas. [Extracted from the article]