VO2 Max: What It Is and Why It Matters?

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By Lucy Watkiss

What is VO2 Max?

Your  VO2 max measures how effectively your heart, lungs and blood vessels transport oxygen to your muscles. It also measures how well your muscles then use that oxygen to produce energy (1).

The V in VO2 max stands for volume. The O2 stands for oxygen. The max stands for maximum. It measures the maximum milliliters of oxygen consumed in one minute per kilogram of body weight.

Exercise physiologists have studied how the human body uses oxygen for a long time. We know that people are always using some oxygen - even at rest. But when you start moving around or exercising, your body starts to use more and more oxygen as the intensity increases.

When you breathe, your lungs absorb oxygen. This oxygen is then transported to your red blood cells which carry the oxygen to your organs and muscles. Your muscle cells need oxygen to generate adenosine triphosphate (ATP). ATP provides the main energy source your muscles need to work (2). The more oxygen you can breathe in, the more ATP your muscles can produce, creating energy to fuel your muscles and power your workout (2). This is one of the reasons that you breathe faster during exercise.

How is our VO2 max measured?

When discussing our VO2 max we could be referring to our absolute or relative VO2 max. In this article we are primarily discussing relative VO2 max but it is useful to know the difference. 

Absolute VO2 max

• Absolute VO2 max measures the total amount of oxygen utilized (expressed as L/min or ml/min).

• To calculate this you need to directly measure oxygen consumption. You would wear a specialist mask connected to a machine capable of analyzing the contents of your respiratory gases.

• The goal is to measure how much oxygen is in the air you breathe in compared to the air you breathe out. The difference is how much body your oxygen is using (3).

• This test is performed in a laboratory.

• The intensity of exercise will gradually increase until you reach the intensity at which the maximum oxygen consumption rate is achieved (3).

• It is uncommon for non-athletes to perform this test.

Relative VO2 max

• Relative VO2 max measures the maximum amount of oxygen an individual can utilise per minute divided by their bodyweight. 

• It measures cardiorespiratory fitness, allowing fair comparisons between individuals of different sizes (3).

If you are not an athlete you do not need to know your exact VO2 max (relative or absolute). However an estimation of maximal aerobic capacity can be calculated from submaximal tests (e.g., the Cooper test or step test) or algorithms using wearable data (e.g., smart watches using heart rate data during exercise) (4). These results are calculated based on the assumption of a linear relationship between heart rate or power output and oxygen consumption during various intensities (4). The American College of Sports Medicine (ACSM) presents widely used and globally recognized guidelines to calculate and predict these measures (5). Researchers have extensively considered the validity and accuracy of predicting VO2 max from a submaximal test, concluding that it allows for a precise estimation, applicable in both a sport and clinical setting (6). Therefore, they are a valuable measuring cardiorespiratory fitness.

Why Is VO2 Max Important?

Now that we have established what our VO2 max is measuring and how it is calculated, we can discuss why it is important to all of us, not just athletes. 

First, we must state that a higher VO2 max is better than a lower VO2 max. This means that your body is more efficient at taking oxygen from the air and using it in your muscles. The more oxygen your muscles can get, the more nutrients you can aerobically transform into the energy your muscles use to perform (7). This is important as your metabolic pathways are by far your most efficient source of energy (7).

A higher VO2 max is strongly associated with a lower risk of heart disease, type 2 diabetes and stroke, as evidenced by several epidemiological studies. This is due to improvements in multiple modifiable risk factors associated with these non-communicable diseases, including a raised blood pressure, obesity and raised cholesterol (8, 9, 10). Individuals with a higher VO2 max also tend to have better insulin sensitivity, meaning their body needs less insulin to move glucose into their cells (11). In comparison, a lower VO2 max is often seen in those with prediabetes or type 2 diabetes (11). 

Furthermore, a high VO2 max is associated with a reduced risk of cancer, including head and neck, lung, breast, gastrointestinal and bladder cancers (12). This has been noted within research across all age groups, sex and races (12). There are various biological mechanisms for this, including a reduction in inflammation, immune support, hormonal regulation and metabolic improvements (12).

What is a good VO2 Max?

Unless you are a competitive endurance athlete, a good VO2 max is understood in terms of so-called normal values. These are the VO2 max ranges that researchers have identified within the general population and can vary based on the age and sex of the individual. These are displayed in Table 1 & Table 2 below.

Table 1 - Male VO2 Max Ranges (13).

	Percentile	20-29	30-39	40-49	50-59	60-69	70-79
Superior	95	55.4	54	52.5	48.9	45.7	42.1
Excellent	80	55.1	48.3	46.4	43.9	39.5	36.7
Good	60	45.4	44	42.4	39.2	35.5	32.3
Fair	40	41.7	40.5	38.5	35.6	32.3	29.4
Poor	0-40	< 41.7	< 40.5	< 38.5	< 35.6	< 32.3	< 29.4

Table 2 - Female VO2 Max Ranges (13).

	Percentile	20-29	30-39	40-49	50-59	60-69	70-79
Superior	95	49.6	47.4	45.3	41.1	37.8	36.7
Excellent	80	43.9	42.4	39.7	36.7	33	30.9
Good	60	39.5	37.8	36.3	33	30	28,1
Fair	40	36.1	34.4	33	30.1	27.5	25.9
Poor	0-40	< 36.1	< 34.4	< 33	< 30.1	< 27.5	< 25.9

As demonstrated above, our VO2 max often decreases as we age. However, our cardiorespiratory fitness losses can be managed through healthy lifestyle choices and regular physical activity. We will discuss this further later in the article.

VO2 Max in Men vs Women

As demonstrated in Tables 1 & 2, there is a variation in VO2 max compared to men and women. This often comes down to differences in body composition. Men typically have more lean muscle mass than women as women tend to naturally accumulate more fatty tissue (15). These natural differences are important for understanding what your personal VO2 max means. In simple terms, muscle utilizes oxygen, whereas fat is simply stored energy (15). Therefore, men will likely have a higher VO2 max due to having a greater muscle mass to use oxygen.

How Can I Improve my VO2 Max?

The good news is that you can improve your VO2 max with simple lifestyle changes no matter your age. 

First of all, make sure you are exercising regularly.  For adults between the ages of  18 and 64 you should be engaging in at least 150 minutes of moderate-intensity aerobic activity per week (or 75 minutes of vigorous activity), along with strengthening exercises at least twice a week (5). 

If you are already active, that’s great. However, there are still some simple changes that could help improve your VO2 max and therefore cardiorespiratory fitness further.  

To do this you should consider the FITT principle. This refers to the frequency, intensity, time and type of exercise that you engage in.

Frequency 

This refers to how many days a week you exercise. It depends a lot on how much time you are able to dedicate to exercise. For example, if you do a lot of lower-intensity exercise (like walking or swimming) you might want to consider doing five 30 minute sessions a week. But if you are going to do more vigorous activities such as a 30 minute HIIT (high-intensity internal training) workout, you may only do this two or three times a week.

Intensity 

This refers to how much you are getting your blood pumping during exercise. As a guide, during moderate intensity aerobic exercise you can talk but not sing but during vigorous exercise you cannot say more than a few words without pausing for a breath (15, 16). Depending on the type of exercise you enjoy or the amount of time you have during the week, the intensity of your exercise may vary. 

Time 

As discussed above, the ACSM guidelines recommend engaging in at least 150 minutes of moderate-intensity aerobic activity per week (or 75 minutes of vigorous activity), along with strengthening exercises at least twice weekly (5). Depending on your schedule you may choose to meet these recommendations by taking a brisk 30 minute walk 5 days a week, or a quick 15 minute HIIT workout 5 days a week. Alternatively, you could mix the two and incorporate both moderate and vigorous intensity exercise into your routine. This also goes back to the frequency of your exercise and what would work for you as an individual. 

Type 

This refers to the type of exercise you do. The most important thing is finding something that you enjoy. This will mean you are more likely to be consistent with your exercise program. Just don’t forget to include both cardiovascular exercise and strength activity into your routine.

Common Training Errors Affecting VO2 Max

Over time your exercise plan will need to be adjusted as your cardiorespiratory fitness increases. Perhaps that walk around the block no longer gets your heart rate up so you need to push yourself a little more to get the same benefit (16). However, there are some common mistakes that people make when trying to improve their VO2 max and cardiorespiratory fitness. These are discussed below: 

1. Doing too much too soon - overtraining without adequate rest can prevent your muscles from adapting and repairing appropriately. It can also cause exhaustion and soreness which makes it harder to remain consistent. To prevent this, only increase one FITT principle at a time (17).

2. Sticking to only one form of exercise - this causes plateaus in your fitness and can limit muscle development. This can also increase your risk of overuse injuries (18). Try mixing up your workouts throughout the week. 

3. Not prioritizing rest - this can prevent the body from properly preparing muscle tissue. Without vital rest periods your fitness can plateau and your risk of injury can increase (18, 19).

4. Not fueling correctly - this can limit your body’s ability to produce energy, repair muscle tissue and maintain a healthy immune system. Without proper nutrients, you may experience early fatigue and a higher risk of injury (20).

5. Skipping your warm up - your warm up prepares your joints and muscles for exercise so skipping them can increase injury risk (17).

6. Skipping your cool down - your cool down enables your muscles and joints to recover properly (17).

7. Ignoring your body signals - pushing through pain can cause serious injury (17). If you experience pain during exercise you should stop and seek medical advice.

References

1. Wagner PD. Determinants of maximal oxygen consumption. Journal of Muscle Research and Cell Motility. 2022 Nov 25;44.

2. Srivastava S, Tamrakar S, Nallathambi N, Vrindavanam SA, Prasad R, Kothari R. Assessment of Maximal Oxygen Uptake (VO2 Max) in Athletes and Nonathletes Assessed in Sports Physiology Laboratory. Cureus [Internet]. 2024 May 26;16(5). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11197041/

3. ‌Warner A, Vanicek N, Benson A, Myers T, Abt G. Agreement and relationship between measures of absolute and relative intensity during walking: A systematic review with meta-regression. Murias JM, editor. PLOS ONE. 2022 Nov 3;17(11):e0277031.

4. ‌Santtila M, Häkkinen K, Pihlainen K, Kyröläinen H. Comparison Between Direct and Predicted Maximal Oxygen Uptake Measurement During Cycling. Military Medicine [Internet]. 2013 Feb;178(2):234–8. Available from: https://academic.oup.com/milmed/article/178/2/234/4210885

5. ACSM. ACSM’s Guidelines for Exercise Testing and Prescription [Internet]. ACSM. 2025. Available from: https://acsm.org/education-resources/books/guidelines-exercise-testing-prescription/

6. ‌Szczepan Wiecha, Przemysław Seweryn Kasiak, Szwed P, Kowalski T, Igor Cieśliński, Marek Postuła, et al. VO2max prediction based on submaximal cardiorespiratory relationships and body composition in male runners and cyclists: a population study. eLife [Internet]. 2023 May 10;12. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10198721/

7. Srivastava S, Tamrakar S, Nallathambi N, Vrindavanam SA, Prasad R, Kothari R. Assessment of Maximal Oxygen Uptake (VO2 Max) in Athletes and Nonathletes Assessed in Sports Physiology Laboratory. Cureus [Internet]. 2024 May 26;16(5). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11197041/

8. ‌Kang SJ, Ko KJ. Association between resting heart rate, VO2max and carotid intima-media thickness in middle-aged men. IJC Heart & Vasculature [Internet]. 2019 Jun;23:100347. Available from: https://www.sciencedirect.com/science/article/pii/S235290671930034X#bb0065

9. ‌McMURRAY RG, AINSWORTH BE, HARRELL JS, GRIGGS TR, WILLIAMS OD. Is physical activity or aerobic power more influential on reducing cardiovascular disease risk factors? Medicine & Science in Sports & Exercise. 1998 Oct;30(10):1521–9.

10. ‌Cilli Hayıroğlu S, Uzun M. Predictive role of peak VO2 for short- and long-term major adverse cardiac events in patients with high cardiovascular risk. Herz. 2024 Oct 14;50(2):142–7.

11. ‌Macedo ACP de, Schaan CW, Bock PM, Pinto MB de, Botton CE, Umpierre D, et al. Cardiorespiratory fitness in individuals with type 2 diabetes mellitus: a systematic review and meta-analysis. Archives of Endocrinology and Metabolism [Internet]. 2023 Sep 25 [cited 2023 Sep 27];67(5):e230040. Available from: https://pubmed.ncbi.nlm.nih.gov/37738467/

12. ‌Kunutsor SK, Kaminsky LA, Lehoczki A, Laukkanen JA. Unraveling the link between cardiorespiratory fitness and cancer: a state-of-the-art review. GeroScience. 2024 Jun 3;

13. ‌ Standard/Solar/Pro Series Owner’s Manual - VO2 Max. Standard Ratings [Internet]. Garmin.com. 2025. Available from: https://www8.garmin.com/manuals/webhelp/GUID-C001C335-A8EC-4A41-AB0E-BAC434259F92/EN-US/GUID-1FBCCD9E-19E1-4E4C-BD60-1793B5B97EB3.html

14. ‌Fleg JL, Morrell CH, Bos AG, Brant LJ, Talbot LA, Wright JG, et al. Accelerated Longitudinal Decline of Aerobic Capacity in Healthy Older Adults. Circulation. 2005 Aug 2;112(5):674–82.

15. ‌Stavrinou PS, Astorino TA, Giannaki CD, Aphamis G, Bogdanis GC. Customizing intense interval exercise training prescription using the “frequency, intensity, time, and type of exercise” (FITT) principle. Frontiers in Physiology. 2025 Apr 3;16.

16. Defne Kaya Utlu. Description, Types, and Prescription of the Exercise. Springer eBooks. 2023 Jan 1;3–18.

17. Kreher JB, Schwartz JB. Overtraining Syndrome. Sports Health: A Multidisciplinary Approach [Internet]. 2012;4(2):128–38. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435910/

18. ‌Aicale R, Tarantino D, Maffulli N. Overuse injuries in sport: a comprehensive overview. Journal of Orthopaedic Surgery and Research. 2018 Dec;13(1).

19. ‌Gong M, Sun M, Sun Y, Jin L, Li S. Effects of Acute Sleep Deprivation on Sporting Performance in Athletes: A Comprehensive Systematic Review and Meta-Analysis. Nature and Science of Sleep. 2024 Jul 1;Volume 16:935–48.

20. ‌Amawi AT, Al-Kasasbeh WJ, Jaradat M, Almasri A, Alobaidi S, Hammad A, et al. Athletes’ nutritional demands: a narrative review of nutritional requirements. Frontiers in Nutrition [Internet]. 2024 Jan 18;10(10). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10848936/

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