People often look for simple ways to measure fitness: body weight, running speed, walking distance or how long they can exercise before becoming tired. VO2max offers a different perspective because it measures the body’s ability to take in, transport and use oxygen during demanding exercise.

VO2max, or maximal oxygen uptake, is one of the most widely used measures of cardiorespiratory fitness. It reflects the integrated performance of the lungs, heart, circulation and working muscles during exercise.

A higher VO2max generally indicates greater aerobic capacity, but there is no single number that defines “good” fitness for everyone. Age, sex, body size, training status, health conditions and the method used to measure or estimate VO2max can all influence the result.

What matters most is understanding what your result means in context and, where appropriate, looking for practical ways to improve or maintain your cardiorespiratory fitness.

What Exactly Is VO2max?

VO2max is the highest rate at which the body can take in and use oxygen during strenuous exercise. It is usually expressed as millilitres of oxygen per kilogram of body weight per minute (mL/kg/min).

During exercise, oxygen is taken into the lungs, transferred into the bloodstream and delivered to working muscles. The muscles then use oxygen as part of the energy-producing processes required to sustain exercise.

Because several physiological systems contribute to the result, VO2max is commonly used as a measure of cardiorespiratory fitness rather than simply lung function or cardiovascular fitness on its own.

VO2max is especially useful when comparing a person’s fitness with appropriate reference populations or monitoring changes over time. It is not, however, a complete measure of health.

Why VO2max Changes With Age

VO2max generally declines with age. Research in healthy adults has demonstrated an age-related reduction in maximal aerobic capacity, although the rate of decline varies considerably between individuals and study populations.

Age-related changes can involve several parts of the oxygen-delivery system, including:

• Cardiovascular capacity: maximum heart rate and other measures of cardiovascular performance tend to change with age.
• Muscle mass and function: reductions in muscle mass and physical activity can affect exercise capacity and how effectively muscles use oxygen.
• Blood flow: changes in blood vessels and cardiovascular function can influence the delivery of oxygen to working tissues.
• Oxygen extraction: skeletal muscle can become less efficient at extracting and using oxygen with advancing age.

These changes do not mean that declining fitness is unavoidable at a fixed rate. Physical activity, training status, body composition, health conditions and other lifestyle factors can all influence an individual’s fitness level.

For that reason, age should be used as context rather than as a prediction of what your personal VO2max must be.

So What Counts As A “Good” VO2max?

There is no single VO2max number that is considered good for every person.

Fitness reference tables typically divide results into categories according to age and sex. These tables are normative references, meaning they describe how a person’s result compares with a particular population. They are not universal medical targets.

The Cooper Institute, for example, has published age- and sex-specific fitness norms. Other research groups and laboratories use different reference populations and testing methods, so the category assigned to a particular VO2max can vary depending on the source.

This distinction matters. A result described as “fair” or “good” on one reference chart should not automatically be interpreted as a diagnosis, a prediction of an individual’s lifespan, or a statement about whether a person is medically healthy.

For an individual assessment, your result is most useful when it is interpreted using the reference standard appropriate to your age, sex, testing method and clinical context.

Examples Of Age-Related Fitness Norms

Reference values generally show that expected VO2max decreases with age in both men and women. However, the exact category boundaries vary between normative datasets.

Age group	What the reference data generally show
20–29	Typically the highest adult reference values, with wide differences between less active and highly trained individuals.
30–39	VO2max remains highly variable, with regular training potentially resulting in substantially higher values than those seen in inactive populations.
40–49	Average reference values generally decline compared with younger adult groups, but individual fitness remains highly variable.
50–59	Age-related decline becomes more evident in population data, while regular physical activity remains an important influence on fitness.
60+	Reference values are generally lower than in younger adults, but there remains a broad range of fitness levels among older people.

These broad patterns are more useful than treating one published table as a universal standard. When a laboratory provides a VO2max report, its own reference range or the specific reference dataset used should be taken into account.

Why VO2max Matters For Health

VO2max is not only relevant to athletes. Cardiorespiratory fitness is consistently associated with important health outcomes in adults.

Large observational studies and meta-analyses have found that higher cardiorespiratory fitness is associated with lower all-cause mortality risk. This does not mean that a higher VO2max directly prevents death or that improving VO2max guarantees a particular health outcome. Rather, it indicates that cardiorespiratory fitness is an important marker of overall physiological capacity and health.

Higher fitness is also associated with lower risk of several cardiovascular and metabolic conditions in population research. The strength of these associations can vary according to the population studied and the outcome being considered.

There are practical reasons to care about fitness as well. Better aerobic capacity can support activities such as walking, climbing stairs, cycling and other forms of sustained physical activity.

VO2max And Longevity: What Does The Evidence Actually Show?

Cardiorespiratory fitness has been described in research as an important predictor of long-term health outcomes. A large meta-analysis of more than two million participants found an inverse association between cardiorespiratory fitness and all-cause mortality, meaning that people with higher fitness levels tended to have lower mortality risk.

A more recent overview of meta-analyses also found a consistent relationship between higher cardiorespiratory fitness and lower risk of mortality and several major health outcomes.

These findings are important, but they need to be interpreted correctly. Most of this evidence is observational. It shows an association rather than proving that changing a person’s VO2max by a specific amount will produce a specific increase in lifespan.

VO2max should therefore be considered one useful marker within a broader assessment of cardiovascular fitness and health rather than a standalone prediction of longevity.

Can You Improve VO2max As You Get Older?

Yes. Age is associated with a decline in VO2max, but fitness is also influenced by physical activity and training.

Research has shown that regular aerobic exercise can improve cardiorespiratory fitness. The magnitude of change depends on the starting level of fitness, the type and amount of training, consistency, recovery, health status and other individual factors.

Someone who is currently inactive can therefore have considerable scope to improve their aerobic capacity, even later in life.

Australian movement guidelines recommend that adults undertake moderate- to vigorous-intensity physical activity on most days, together with muscle-strengthening activity on at least two days each week. The appropriate amount and intensity should be adjusted for individual health status and physical capacity.

How To Improve VO2max

Build A Sustainable Aerobic Base

If you are currently inactive or returning to exercise, starting with manageable activities is often the most practical approach. Brisk walking, cycling, swimming and other aerobic activities can help build exercise tolerance before more demanding training is introduced.

The goal is consistency rather than trying to perform every session at maximum intensity.

Add Higher-Intensity Work Gradually

Once an aerobic base is established, periods of higher-intensity exercise can be incorporated into a training programme. Interval training is one established approach to improving cardiorespiratory fitness, although the appropriate intensity and duration depend on the individual.

Harder intervals do not need to be performed by everyone, and people with cardiovascular disease, significant health conditions or symptoms during exercise should obtain appropriate medical advice before undertaking strenuous training.

Keep Strength Training In The Programme

VO2max measures aerobic capacity, but cardiovascular fitness should not be viewed separately from overall physical function.

Strength training supports muscle strength and function and is recommended as part of Australia’s physical activity guidelines. It can complement aerobic training rather than replace it.

Allow Adequate Recovery

Training adaptations occur alongside recovery. Sleep, nutrition, rest days and sensible progression all matter when building fitness.

Doing more exercise is not automatically better. Training volume and intensity should increase progressively, particularly after a period of inactivity.

How VO2max Is Tested

The most direct way to measure VO2max is through cardiopulmonary exercise testing (CPET). During the test, a person exercises on equipment such as a treadmill or cycle ergometer while breathing through a mask or mouthpiece connected to gas-analysis equipment.

The system measures oxygen uptake and carbon dioxide output while exercise intensity increases. Heart rate and other physiological measurements can also be monitored during the assessment.

Protocols vary. The Bruce treadmill protocol is one commonly used exercise-testing protocol, but it is not the only method available and is not automatically the most appropriate protocol for every person.

A properly conducted maximal test generally aims to determine maximal or near-maximal exercise capacity. Whether someone should perform a maximal test depends on their health, symptoms, fitness and the purpose of the assessment.

Submaximal exercise tests and validated non-exercise methods can also be used to estimate cardiorespiratory fitness, although an estimate is not the same as a directly measured VO2max.

VO2max, VO2peak And Exercise Thresholds

Fitness reports can contain several different measurements, and they should not automatically be treated as interchangeable.

• VO2max: the maximum oxygen uptake achieved under appropriate testing conditions.
• VO2peak: the highest oxygen uptake recorded during a test when definitive criteria for VO2max are not established or achieved.
• Ventilatory thresholds: points during increasing exercise intensity where ventilation changes relative to oxygen uptake and carbon dioxide production. These can provide useful information about exercise tolerance and training intensity.

The terminology used in a report can therefore depend on the testing protocol and the physiological criteria achieved during the assessment.

Do You Need A VO2max Test?

Not everyone needs a formal VO2max assessment.

For many healthy adults, following physical activity guidelines and gradually building regular aerobic exercise can be a more practical priority than obtaining an exact laboratory measurement.

A formal assessment may nevertheless be useful when someone wants a more detailed evaluation of cardiorespiratory fitness, is involved in structured athletic training, or is undergoing exercise assessment for a particular clinical or performance-related reason.

Any testing programme should consider the person’s medical history, symptoms and exercise experience. Chest pain, unexplained breathlessness, fainting, palpitations or other concerning symptoms during exercise warrant medical assessment rather than simply trying to improve a fitness score.

What Can Affect Your VO2max Result?

A VO2max result is influenced by more than age.

• Training status: Regular aerobic exercise generally supports higher cardiorespiratory fitness.
• Body composition: VO2max is commonly expressed relative to body weight, so changes in body mass can affect the value reported in mL/kg/min.
• Testing protocol: Different protocols and equipment can produce different results.
• Effort and test completion: A submaximal effort may produce a VO2peak or estimated value rather than a true VO2max.
• Health status: Cardiovascular, respiratory, metabolic and other medical conditions can influence exercise capacity.

This is one reason why comparing two VO2max values is most useful when the tests have been performed under comparable conditions.

What About Smartwatches And Fitness Trackers?

Many wearable devices estimate VO2max from exercise data such as heart rate, speed, pace and movement. These estimates can be useful for tracking trends, especially when the same device and similar activity conditions are used consistently.

However, a wearable estimate is not equivalent to directly measured VO2max from a laboratory CPET. Accuracy can vary according to the device, activity, individual characteristics and data available to the algorithm.

For that reason, a wearable VO2max estimate should generally be treated as a fitness-tracking metric rather than a diagnostic measurement.

Common VO2max Myths

Myth: There Is One Perfect VO2max Number For Each Age

Reality: Reference values provide population comparisons, not a universal target that every person of the same age should achieve.

Myth: A High VO2max Means You Are Completely Healthy

Reality: VO2max is one marker of cardiorespiratory fitness. It does not assess every aspect of health, including blood pressure, cholesterol, mental health, strength, flexibility, nutrition or other medical conditions.

Myth: VO2max Only Matters For Athletes

Reality: Cardiorespiratory fitness is relevant to everyday physical capacity as well as sport.

Myth: VO2max Must Decline At The Same Rate For Everyone

Reality: Fitness changes with age, but the rate of change varies considerably between individuals and is influenced by activity and health status.

Myth: The Highest Possible VO2max Is Always The Goal

Reality: Training goals should be appropriate to the individual. A sustainable exercise routine that improves or maintains fitness is generally more useful than chasing an arbitrary number.

Putting Your VO2max Into Perspective

If your result is lower than you expected, it does not mean that you have failed or that your health is necessarily poor. It provides information about your current aerobic capacity.

Likewise, a high result is something to understand rather than a guarantee of long-term health.

Tracking changes over time can sometimes be more useful than focusing on a single result. If your testing method is consistent and your fitness improves, an upward trend can provide useful feedback that your training is producing physiological adaptation.

For older adults in particular, maintaining aerobic fitness alongside strength, mobility and balance can support physical independence and participation in everyday activities.

Why VO2max Can Be Useful In A Broader Health Assessment

VO2max does not tell the whole health story, but it can provide information that is difficult to capture from measurements such as body weight alone.

Cardiorespiratory fitness reflects the combined capacity of several systems during exercise. Used alongside medical history, blood pressure, metabolic health, strength, body composition and other relevant measures, it can contribute to a broader understanding of physical health.

Any interpretation should remain proportionate. A VO2max result is a physiological measurement, not a standalone prediction of future disease or an automatic indication for treatment.

Final Thoughts

There is no single “good” VO2max that applies to everyone at a particular age. Population reference values can help provide context, but your result needs to be interpreted according to your age, sex, testing method, training status and health.

VO2max generally declines with age, but regular physical activity can help maintain and improve cardiorespiratory fitness. Australian guidelines recommend regular moderate- to vigorous-intensity activity together with muscle-strengthening and functional activity.

A formal VO2max assessment can provide a detailed snapshot of aerobic capacity when there is a clear reason to measure it. For others, simply becoming more consistently active may be the most important first step.

At Longevity Clinics, VO2max assessment can be considered as one component of a broader health and fitness evaluation. The value of the measurement comes from putting the result into context and using it to inform sensible, individualised exercise and health decisions rather than chasing a single number.