How is cardiorespiratory fitness measured?

Cardiorespiratory fitness is measured through VO2max testing. VO2max is essentially a measurement of the maximum amount of oxygen that your body is capable of consuming to generate energy that can be used at the cellular level. 

The gold standard by which cardiorespiratory fitness is measured requires a VO2max test under laboratory controlled settings with sophisticated equipment. However, if you don't have access to a laboratory equipped for VO2max measurement it is still possible to make a very reasonable estimate of your personal VO2max by trying the Rockport one mile walk test or the 3 minutes step up test.

Cardiorespiratory fitness is measured by assessing the VO2 Max, which Dr. Traver has described above.  The most common way of assessing the VO2 max is by performing the Rockport Walk Test.  The heart rate is determined at the 1-mile mark and then a formula is used to determine the score.  This score will determine whether the person falls into the Poor, Fair, Average, Good, or Very Good category.
The best method to measure cardiorespiratory fitness is by measuring VO2Max, which is a calculation of how efficiently your body can transport and uitlize oxygen. To get an accurate measurement, expensive and extensive equipment is needed.

Professionals are however able to estimate a person's maximum VO2, or determine a starting point for a cardiorespiratory conditioning program by performing a sub-maximal test, and then using an equation to come to a result. Some tests that are often used include the 3-Minute Step Test, and the Rockport Walk Test. Results for these tests are compared to a normative charts, and from there, fitness can be evaluated.
Cardiorespiratory fitness is the ability to perform dynamic exercise using large muscle groups at moderate to high intensity for prolonged periods . VO2 max is considered to be the most valid measure of cardiorespiratory fitness. It measures the capacity of the heart, lungs, and blood to transport oxygen to the working muscles, and measures the utilization of oxygen by the muscles during exercise. One way to test is using the Rockport Fitness test. This is performed best on a treadmill. Walk as fast as possible and while being safe for one mile, then measure heart rate and time as soon as the mile is complete. You want to make sure you weigh yourself before the test. Then calculate using this formula.

VO2 max = 88.02 - .1656 (body weight in kg*) – 2.76 (time in minutes†) + 3.716 (gender‡)

88.02 - .1656 ( _______ kg ) – 2.76 ( ______ min ) + 3.716 ( ____ ) = _________ Your VO2 max

* Body weight in kg = weight in pounds ÷ 2.2

† Time in minutes: Convert seconds to minutes by dividing the seconds by 60.

Cardiorespiratory fitness can be a slippery slope of understanding.  Many individuals perceive cardiorespiratory fitness as being 'in-shape' and in turn equates this to being thin or skinny.  Cardiorespiratory fitness or being 'in-shape' actually refers to how well your body processes oxygen.  Being thin or skinny does not necessarily mean that the individual is 'in-shape'. Many individuals who have heavier body types have greater cariorespiratory fitness than there thinner counterparts. 

Cardiovascular fitness refers to how efficiently the heart and lungs can send oxygenated blood to the working muscles of the body, so that they might continue performing work. As the intensity level of the exercise increases, the level of oxygen that the body utilizes to continue the effort increases, along with the levels of carbon dioxide and lactic acid, which are the metabolic waste products produced by the exercise…This process goes on until you cannot voluntarily continue with the exercise and have to stop. The measurement of a persons cardiovascular fitness is typically referred to by many as measuring V0-2 max. V0-2 max is the body’s maximal ability to utilize oxygen to perform work. In actuality, there are very few people who can voluntarily work hard enough to reach their V0-2 max. This is because V0-2 max is exactly what it means; Maximal work output, just before complete physiological crash, and not voluntarily sustainable for any meaningful period of time.  

Actual measurement of V0-2 max outside of a clinical setting can be extremely risky,  due to scope of practice issues, as well as the need for the emergency equipment required. In a health and fitness setting, V02 max is typically plotted from extrapolating the results of a much safer sub-maximal test, such as a physical work capacity test on a bicycle ergometer or treadmill. However, a V02 max test is a poor choice for answering the more practical question that people really want to know, which is; What is their maximal sustainable cardiovascular ability to perform exercise?

A term known as V0-2 peak is a more usable measurement of cardiovascular fitness, as it pertains to the body’s ability to perform a maximally sustained aerobic effort. From a heart rate perspective, it is very close to and just prior to something called metabolic acidosis, in which the level of carbon dioxide being produced by the body begins to exceed the amount of oxygen the body can physically take in, which in turn quickly leads to V0-2 Max.

The difference is that V02 peak represents a voluntary maximal effort. Therefore, V0-2 peak is a more usable, real world measurement of cardiovascular fitness. The ultimate goal is more efficient fat utilization by the body over time, which leads to more effective weight loss and a higher level of cardiovascular fitness.

Kelly Traver
Internal Medicine

Cardiorespiratory fitness is measured by assessing VO2 max, which is a measure of how much oxygen your body absorbs and utilizes during peak exercise. The higher the VO2 max, the better your fitness.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.