How does aerobic exercise prevent cardiovascular diseases? it you burn more calories, which reduces plaque in the arteries, so that your heart becomes more efficient at pumping blood. it warms your blood, making it more fluid, so that your heart can pump more efficiently and slowly, creating less stress on the heart. it makes your heart beat faster to supply more oxygen, which makes the heart stronger and enables it to pump blood more efficiently. it lowers your blood pressure, which allows your heart to better dispose of fat cells before they form plaque on the artery walls.