Heart rate monitoring during exercise provides real-time feedback on how hard you are working and if the activity needs to be increased or lowered for a safe, effective workout. Keeping track of your heart rate can give you insight into your fitness level, heart health and emotional health. To properly and effectively train around your heart rate, you need to know what your resting heart rate, maximum heart rate. During exercise, your heart typically beats faster so that more blood gets out to your body. Your heart can also increase its stroke volume by pumping more forcefully or increasing the amount of blood that fills the left ventricle before it pumps.