What is VO2 Max?
You may have heard the term VO₂ max mentioned in conversations about longevity and cardiovascular fitness. Maybe you’ve seen a VO₂ max estimate on your smartwatch. But what exactly does it measure, and is it something you should know?
VO₂ max is one of the best-established measures of cardiorespiratory fitness (CRF). It indicates how well your body can take in oxygen, deliver it to working muscles, and use it during physical activity.
Increasingly, CRF is recognized as an important marker of cardiovascular health and overall health. Recent research has consistently linked higher levels of CRF with a lower risk of cardiovascular disease and premature death. [1,2].
What Is VO₂ Max?
VO₂ max stands for maximal oxygen uptake. It represents the greatest amount of oxygen your body can use during strenuous exercise. It is usually reported as milliliters of oxygen used per kilogram of body weight per minute, or mL/kg/min.
Although we often think of VO₂ max simply as a measure of “fitness,” it reflects the combined work of several systems in the body. Your lungs bring oxygen into the body, while your heart and blood vessels circulate oxygen-rich blood, and your muscles extract and use that oxygen to produce energy.
For this reason, VO₂ max provides information about how effectively the heart, lungs, circulation, and muscles work together during exercise [3].
How Is VO₂ Max Tested?
The most accurate way to measure VO₂ max is through cardiopulmonary exercise testing (CPET).
During a CPET, you exercise on a treadmill or stationary bicycle while the workload gradually becomes more challenging. You wear a mask connected to specialized equipment that measures the oxygen you inhale and the carbon dioxide you exhale.
Depending on the setting and reason for testing, your heart rate, blood pressure, heart rhythm, breathing pattern, oxygen levels, and symptoms may also be monitored.
As exercise intensity increases, the equipment measures how much oxygen your body is able to use. The highest oxygen uptake achieved during the test provides your VO₂ max or, depending on the testing circumstances, a closely related measurement called peak VO₂.
CPET is considered the gold-standard method for measuring cardiorespiratory fitness because it provides an integrated assessment of the cardiovascular, respiratory, and muscular response to exercise [3].
What Is a “Good” VO₂ Max?
There is no single ideal VO₂ max for everyone. Results vary based on factors such as age, sex, fitness level, and the type of test performed.
For this reason, VO₂ max is best interpreted using age- and sex-specific reference ranges rather than comparing your result with one universal number [4]. It can also be useful to track your own changes over time as your fitness improves.
What Does VO₂ Max Tell Us About Cardiovascular Health?
Your VO₂ max gives us another way to look at how well your heart, lungs, circulation, and muscles work together when your body is under greater demand.
That matters because higher cardiorespiratory fitness is consistently associated with better cardiovascular health and a lower risk of premature death.[1,2]
Of course, VO₂ max is only one piece of the picture. It does not tell us on its own whether you will develop heart disease, and it does not replace the other indicators we already pay attention to such as blood pressure, cholesterol, blood sugar, family history, sleep, nutrition, physical activity, and overall health.
What it can do is give us useful information about how efficiently your body responds to exercise and how strong your cardiorespiratory fitness is right now. That can be helpful alongside the other health information we use to understand your cardiovascular risk and overall wellness. Testing VO₂ max over time shows how your performance changes as you age, helping us tailor lifestyle recommendations to protect or enhance your health.
Who Might Consider VO₂ Max Testing?
VO₂ max testing may be useful for people who want to:
Establish a baseline of cardiorespiratory fitness
Track changes in fitness over time
Personalize aerobic exercise intensity
Guide endurance or performance training
It may also be used in cardiac or pulmonary rehabilitation and in some clinical settings to assess exercise capacity and help guide care [3].
Can You Improve Your VO₂ Max?
For many people, VO₂ max can improve with regular aerobic exercise. Activities such as brisk walking, cycling, swimming, jogging, and rowing all challenge the heart and lungs and can help build cardiorespiratory fitness over time.
How much your VO₂ max changes will vary from person to person. Factors such as age, overall health, starting fitness level, and regular physical activity can all influence cardiorespiratory fitness and how it responds to exercise [5,6].
The important takeaway is that cardiorespiratory fitness can be improved throughout life. Starting at your current fitness level and gradually building regular aerobic activity can strengthen your body’s ability to deliver and use oxygen more efficiently.
Talking to your Synergy physician is a great way to determine if you are a good candidate for VO₂ max testing. While we do not perform CPET onsite, we work with our Synergy Wellness Partners to help you obtain this study. Once we have your VO₂ max results, your clinician can help you interpret the findings, and our Synergy Health Coaches can support you with personalized lifestyle and fitness goals. Together we can help you create a realistic and sustainable plan, build consistency, and take meaningful steps toward improving your overall health and fitness.
References
Lang JJ, Prince SA, Merucci K, et al. Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: An overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies. Br J Sports Med. 2024;58(10):556-566. doi:10.1136/bjsports-2023-107849
Singh B, Cadenas-Sanchez C, da Costa BGG, et al. Comparison of objectively measured and estimated cardiorespiratory fitness to predict all-cause and cardiovascular disease mortality in adults: A systematic review and meta-analysis of 42 studies representing 35 cohorts and 3.8 million observations. J Sport Health Sci. 2025;14:100986. doi:10.1016/j.jshs.2024.100986
Dores H, Mendes M, Abreu A, et al. Cardiopulmonary exercise testing in clinical practice: Principles, applications, and basic interpretation. Rev Port Cardiol. 2024;43(9):525-536. doi:10.1016/j.repc.2024.01.005
Kaminsky LA, Arena R, Myers J, et al. Updated reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: Data from the Fitness Registry and the Importance of Exercise National Database (FRIEND). Mayo Clin Proc. 2022;97(2):285-293. doi:10.1016/j.mayocp.2021.08.020
Börjesson M, Ekblom Ö, Arvidsson D, et al. Correlates of cardiorespiratory fitness in a population-based sample of middle-aged adults: cross-sectional analyses in the SCAPIS study. BMJ Open. 2022;12(12):e066336. doi:10.1136/bmjopen-2022-066336.
Crowley E, Powell C, Carson BP, Davies RW. The effect of exercise training intensity on VO₂max in healthy adults: an overview of systematic reviews and meta-analyses. Transl Sports Med. 2022;2022:9310710. doi:10.1155/2022/9310710.