Exercise and physical activity is stressful to the body. When you exercise, you increase the demand for blood and nutrients to your working muscles, which means your heart must work harder. Your heart compensates by increasing the rate at which it pumps. It is by this means that the heart is able to perform its functions: delivering oxygen, picking up oxygen, cooling off the body, delivering nutrients and hormones.
Response to Exercise
Your cardiovascular system's response to exercise is directly proportionate to the intensity at which you are working --- in other words, the harder you work, the higher your heart rate will go to fulfill the need for additional blood flow. Your fitness level dictates the maximum amount of work your body can do. Once you have reached this intensity, the Sports Fitness Advisor website explains, the heart is not able to further speed the delivery of blood and your heart rate plateaus.
Normal Increases
Your heart rate should increase in a normal, linear fashion. It should stay in rhythm, meaning it beats in a continuous fashion that feels and sounds steady. The increase in your heart rate with exercise depends on your fitness and how intensely you are exercising. To be sure you are exercising safely, you can estimate your maximum heart rate by subtracting your age from 220. This will give you an idea of your heart's maximum capability of work. From there, you can judge your intensity.
Regulation of Your Heart Rate
You may notice your heart rate increasing before you even start exercise. This is known as the anticipatory rise in heart rate and occurs due to the innervation of your brain on your heart, Sports Fitness Advisor explains. Several factors work together to regulate your heart rate while you exercise, including feedback regarding the pH balance of your blood. Changes in heart rate and blood pressure are made by the brain to allow your body to do the work.
Adaptations to Exercise
During regular exercise, your body changes to meet the demands placed upon it. These adaptations allow the heart to pump more blood per beat and deliver more nutrients to your working muscles. The less your heart must work at a given intensity, the fitter you become. Such adaptations include a larger left ventricle capable of holding and pumping more blood, increased capillarization around your muscles, higher blood volume and lower resting heart rate and blood pressure.
Considerations
If you have any concerns about your heart rate during exercise, discuss your fitness regimen with your doctor.
References
- Sports Fitness Advisor: The Cardiovascular System and Exercise; Phil Davies, CSCS
- "Exercise Physiology"; George A. Brooks, Thomas D. Fahey, Kenneth M. Baldwin; 2005
- Research Center for Stroke and Heart Disease: Is Your Pulse Normal?
