Because you body is working at a faster rate, so the demand for oxygen is increased. So your heart has to pump faster to get more oxygenated blood to circlulate your body (more specifically the...
There are many things that increase while you exercise. They are:
Your breathing rate
Your heart rate
Your calories burning rate
Regular exercise increases many things like
Your fitness
Your...
As your muscles work harder, they need more nutrients. The brain tells the heart to beat faster to provide more nutrients to the muscles. You also breath heavier and more rapidly because your body...