Relationship Between Heart Rate & Cardiovascular Fitness

All healthy adults need exercise. When you exercise regularly you reduce your risk of developing heart disease, obesity, stroke, diabetes and cancer. Additionally, regular exercise improves the function of your cardiovascular and respiratory systems. Cardiovascular fitness is the ability of the body to continue in moderate to vigorous activity, using large muscle groups, for a long period of time. It is also known as cardiorespiratory fitness, cardiovascular endurance or stamina. It is often linked to health. According to the American Heart Association, those with low cardiorespiratory fitness have a higher incidence of cardiovascular disease and premature death.

Cardiovascular Fitness

Cardiovascular fitness is the ability of your heart, lungs and vessels to respond to exercise, adjusting to the increased oxygen needs and then recover efficiently. When your body is able to efficiently deliver oxygen and nutrients to the working muscles, your muscular endurance also improves. As your oxygen delivery system improves, so does the ability of the muscles to extract the oxygen from the blood. The more efficient this process is, the more fit you are.

Measurement

The American College of Sports Medicine recommends measuring oxygen uptake, or VO2 max, to assess cardiovascular fitness. However, the equipment necessary for this evaluation is not widely available. Therefore, a variety of exercise tests that closely predict VO2 max by using heart rate response have been developed. The heart rate response tests are the most often used in fitness settings because they are easier to administer.

Resting Heart Rate

Your heart is the pump that delivers oxygenated blood to all the muscles of your body. Your heart rate is how many times your heart beats in one minute. It reflects how hard your heart must work to meet the oxygen demands of the body. The Mayo Clinic cites an average resting heart rate will range from 60 to 100 beats per minute. With regular exercise, your heart becomes more efficient and pumps out more blood with each beat. Since it is able to pump out more volume, it does not have to beat as often. Therefore, in the more physically fit, your resting heart rate will be lower compared to those who are not as fit.

Exercise Heart Rate

With exercise, your muscles begin to work harder and in turn require more oxygen. Your body naturally responds to physical activity by increasing the heart rate and therefore delivering more oxygen to the working muscles. Your heart rate will increase in a linear fashion with the exercise intensity. If you exercise regularly, you will notice that your heart rate will not increase as much as it did at the same intensity when you started exercising. The ACSM predicts that is because your cardiorespiratory fitness level has improved. Many fitness professionals will periodically repeat the exercise test that they originally used to predict your fitness level to see how your heart rate response has improved with exercise. Most often you will find that when you compare your heart rate with your initial, or baseline, measurements, your heart has become more efficient and does not have to beat as hard for you to complete the same task.

Target Heart Rate

Target heart rates are a range of heart rates that, when you exercise at an intensity that keeps your heart rate in that range, will improve your cardiovascular fitness. The American College of Sport Medicine recommends training above 60 percent of your maximum heart rate, at least 30 minutes a day, three to five days per week to improve your cardiovascular fitness. The American Heart Association notes that low to moderately intense activities such as walking and gardening are beneficial but that vigorous aerobic activities will have the greatest impact on your fitness level.