cardiorespiratory fitness

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Definition - What does cardiorespiratory fitness mean?

Cardiorespiratory fitness is how well the body processes oxygen. It is the ability of the circulatory and respiratory systems to supply oxygen to the skeletal muscles during any sustained physical activity. A VO2 max test is considered the most reliable and valid measurement of cardiorespiratory fitness. The higher the VO2 max result, the better the body is able to deliver oxygen where it is needed in the body. Cardiorespiratory fitness is sometimes called cardiorespiratory endurance.

SureHire explains cardiorespiratory fitness

Cardiorespiratory fitness is important to measure because it provides a diagnostic tool for certain health issues and is a good measure of the amount of work an individual's body can perform. As the intensity level of your exercise increases, the amount of oxygen that the body needs to continue the effort increases, along with levels of carbon dioxide and lactic acid (metabolic waste products created by exercise). The body continues to use oxygen until it cannot do so any longer and the person must stop the exercise. The better a person's cardiorespiratory fitness level, the longer the exercise can be continued.


Cardiorespiratory fitness may be included in fit for work testing for certain job duties or a functional capacity evaluation. Testing for actual VO2 max is best suited for a clinical setting. It is typically plotted from doing physical work tests using a bicycle ergometer, or treadmill, but may also be calculated using a 3-minute step test.


Exercises that are best suited for improving cardiorespiratory fitness include walking, swimming, cycling, and running.

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