posted by sarah on .
How does heart rate increase? Does it double? Does it increase with the intensity of the workout?
I already know the background of heart rate but have trouble with the questions above.
Your body needs oxygen in order to efficiently break down glucose and process it into your cell's primary energy source (ATP). As you do more intense exercise, you need more energy and therefore more oxygen. Your blood carries oxygen from the lungs to your muscles. To keep up with these increased oxygen needs, you have to have more blood going to your muscles. As a result, your heart pumps faster, sending more oxygenated blood to your muscles per second.
btw this is from wiki answers