Introduction
When you exercise, do you notice that you get out of breath? What about feeling your heart rate—your pulse—increasing? These two changes are not coincidental—they are both important, and natural, reactions of your cardiovascular system to exercise.
From your brain down to your fingers and toes, your body needs plenty of oxygen to keep going. That oxygen is carried through your body in the bloodstream. Blood is pumped through the heart and picks up oxygen as it passes by the lungs.
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