Cardiovascular fitness describes the ability and efficiency of your body to supply your organs and tissues with oxygen. The primary components of your cardiovascular fitness are your heart, your lungs and your blood vessels. Your cardiovascular fitness is improved and maintained through aerobic exercise. There are many ways for assessing your cardiovascular fitness, some invasive and complex and others very simple. Heart rate, both at rest and during exercise, is an easy-to-determine indicator of your cardiovascular health.
Cardiovascular Physiology
The function of the heart is to pump blood to your lungs to be oxygenated and then to the rest of your body to provide oxygen to your organs and tissues. Your heart's output is based on how much blood it produces with each contraction and how fast the heart beats. In conjunction, the blood vessels throughout the body dilate and contract to provide organs and tissues with an adequate blood supply.
Cardiovascular Response to Exercise
During exercise, your body needs oxygenated blood delivered to your tissues faster than when at rest. This occurs because your muscles require more oxygen to do work. As a result, your breathing and heart rates increase to keep up with increased demand, and your heart pumps larger amounts of blood as it is able to contract harder. The blood vessels in your muscles dilate to provide greater blood flow while those vessels in your digestive organs contract since blood flow to these areas is not as important during exercise.
Heart Rate and Cardiovascular Fitness
With regular exercise, the cardiovascular system adapts so that it is more efficient at delivering oxygen to working muscles. The heart contributes to this increased efficiency by enlarging the size of the left ventricle, the heart chamber that pumps blood out to the body. Thus the heart has a greater capacity of blood that it can deliver with each contraction. Additionally, trained muscles are more effective at extracting oxygen from blood. The combination of these adaptations to exercise allow for the well-trained heart to beat at a slower rate. As a result, athletes often have a lower heart rate at rest and during exercise than sedentary people. To determine your fitness level based on heart rate, use the three-minute step test protocol (see Resources).
Heart Rate Training Zones
According to the textbook "Essentials of Exercise Physiology," for optimal cardiovascular fitness training you should perform activities that maintain your heart rate at 70 percent to 90 percent of your maximal heart rate. Your maximal heart rate can be estimated by multiplying your age by 0.7 and subtracting the result from 208.
References
- "Ganong's Review of Medical Physiology"; Kim E. Barrett, Ph.D., Susan M. Barman, Ph.D., Scott Boitano, Ph.D., Heddwen Brooks, Ph.D., 2010
- "Essentials of Exercise Physiology"; William D. McArdle, Ph.D, M.Ed., Frank L. Katch, Ph.D, Victor I. Katch, Ph.D.; 2006.
Member Comments