VO2 max test: what it measures and how it is carried out

VO2 max, also called maximal oxygen uptake, is the largest volume of oxygen the muscles can use per minute [2]. It is regarded as an expression of aerobic capacity, that is, the ability to work over time with oxygen as the energy source [2].

A scientific statement from the American Heart Association from 2016 describes fitness, measured as cardiorespiratory fitness, as an indicator that gives information about illness and mortality in addition to the traditional risk factors [4]. This is based on observational studies. It shows associations and is not proof that better fitness alone is the cause.

VO2 max is limited by how well the body delivers oxygen to the muscles and how well the muscles manage to use it [3]. Blood volume and how much oxygen-rich blood the heart pumps per minute set the limits for the delivery [3].

Both genetics and training play a part. A piece from the Norwegian School of Sport Sciences describes that a well-trained person can have roughly twice the oxygen uptake of an untrained person in the same weight class [3]. After three months of endurance training, VO2 max increased by about ten percent on average, but the response varied from no increase to 40 percent between individuals [3].

The load is increased step by step, and the test continues until you are exhausted [1]. At the test laboratory of the University of South-Eastern Norway the steps last 30 to 60 seconds, the test itself takes 4 to 8 minutes, and the whole visit takes 15 to 25 minutes including a 10 to 15 minute warm-up [1]. Oxygen uptake and heart rate are recorded continuously [1].

Oxygen uptake is measured by breathing through a mouthpiece, usually with a nose clip, connected to a machine that measures how much oxygen there is in the air you breathe in and out [3].

The test laboratory recommends that you do not do a hard training session the day before, have your last meal at least one hour before the test and avoid caffeine, snuff and smoking during the last four hours. You should arrive rested and avoid testing in periods of high training load [1].

Because the test goes to exhaustion, participants must fill in a health self-declaration. For people over 60, a medical certificate is required stating that there are no conditions speaking against a test to maximal exhaustion [1]. If you have a known illness or are unsure whether you should be exerted maximally, it is sensible to discuss it with your doctor before booking.

The test gives a fitness value and your maximal heart rate, and can be used as a basis for training planning and for following development over time [1]. A measured maximal heart rate is more accurate than formulas. NHI describes that the old rule 220 minus age is inaccurate, and that a newer formula has a standard deviation of 11 beats per minute. A physical test is therefore recommended to find an accurate value [2].

VO2 max does not tell the whole story, however. Performance in competition also depends on how large a share of VO2 max one can sustain over time and on running economy [3]. How large a share one can sustain can be examined with a lactate profile [1].

There are several ways of assessing fitness. The American Heart Association describes that a minimum is to estimate fitness annually with a non-exercise algorithm, or with submaximal tests and field tests. The ideal is a maximal test, preferably with measurement of gas exchange, carried out at regular intervals [4].

Estimates and direct measurement do not necessarily give the same number. Which method is appropriate depends on what the number is to be used for.

At the Kondisjonsklinikken at Dr.Dropin Bislett the VO2 max test is carried out by running on a treadmill with a breathing mask, and the load is increased gradually until you cannot continue. You get a review of the results and what they may mean for your training. The test can be combined with a lactate profile.

If you have muscle or joint problems that have arisen in connection with running, you can read more about running injuries.

What is VO2 max?

VO2 max is the highest volume of oxygen the muscles can use per minute, and is regarded as a measure of aerobic capacity [2].

How long does a VO2 max test take?

At the test laboratory of the University of South-Eastern Norway the test itself takes 4 to 8 minutes, and the whole visit 15 to 25 minutes including warm-up [1]. The time needed may differ somewhat at other test sites.

Do I have to be tested to exhaustion?

Yes, a VO2 max test continues until exhaustion [1]. Laboratories therefore ask for a health self-declaration, and above 60 years a medical certificate is required [1].

What is maximal heart rate, and how do I find it?

Maximal heart rate is the highest heart rate you can reach. The formula 220 minus age is regarded as inaccurate, and for an accurate value NHI recommends a physical test [2].

Can VO2 max be improved with training?

In the piece from the Norwegian School of Sport Sciences, VO2 max increased by about ten percent on average after three months of endurance training, but the response varied from no increase to 40 percent between individuals [3].

You can read more about the Kondisjonsklinikken and about the lactate profile. You can find more articles in the overview of articles.

This article was written by Dr.Dropin Fysikalske and is based on the sources listed below. It gives general information and does not replace an examination by a healthcare professional.

The websites were accessed and read on 22 October 2026.

1. Idrettsfysiologisk testlaboratorium, campus Bø (Sports physiology test laboratory, campus Bø). University of South-Eastern Norway (USN). Published 26 April 2018, last modified 9 April 2026. Link

2. Kvam M. Aerob og anaerob trening (Aerobic and anaerobic training). NHI.no. Published 10 September 2013, last updated 15 January 2020. Link

3. Øien L. Blodet spiller en viktig rolle i utvikling av god kondisjon (Blood plays an important role in developing good fitness). NIH-podden, Norwegian School of Sport Sciences. Published 17 November 2021, last updated 20 November 2023. Link

4. Ross R, Blair SN, Arena R, Church TS, Després JP, Franklin BA et al. Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign. A scientific statement from the American Heart Association. Circulation. 2016. Link