VO2 Max Guides: Boost Your Fitness with Editable Templates

VO2 max is one of the most widely used measures of aerobic fitness, but a single number means very little without context. A VO2 max of 35 mL/kg/min could be below average for one person, close to average for another and well above average for someone in a different age group. Sex, age, testing method, body size and whether the result was directly measured or estimated all affect interpretation.

That is why asking “is 40 a good VO2 max?” has no universal yes-or-no answer. A better question is: how does my result compare with people of a similar age and sex who were tested in a similar way?

This guide explains what VO2 max measures, gives age- and sex-specific reference values from a large directly measured fitness registry, shows why treadmill and cycle results should not be mixed together, and helps you use your score without turning it into a diagnosis or a competition with somebody whose circumstances are completely different.

Quick answer: a “good” VO2 max is usually best judged against an age-, sex- and test-mode-specific reference distribution. Values around the 50th percentile are around the middle of the reference group, while higher percentiles indicate higher cardiorespiratory fitness relative to that group. VO2 max normally declines with age, is typically higher in men than women on a relative mL/kg/min basis in population reference data, and is usually higher on treadmill testing than cycle ergometry. These are population patterns, not value judgements about an individual.

What is VO2 max?

VO2 max describes the maximum rate at which your body can take in, transport and use oxygen during intense exercise. It reflects the combined performance of the lungs, heart, circulation and working muscles. The usual relative unit is millilitres of oxygen per kilogram of body weight per minute, written mL/kg/min.

A laboratory cardiopulmonary exercise test can directly measure oxygen uptake while exercise intensity increases. You wear a mask or mouthpiece connected to gas-analysis equipment while exercising on a treadmill or cycle ergometer. The test records how much oxygen you consume and carbon dioxide you produce. Depending on the protocol and physiological response, the highest value may be described as VO2max or VO2peak.

Sports watches, running tests and gym machines often estimate VO2 max instead. These estimates can be useful for tracking trends, but they should not automatically be treated as equivalent to directly measured laboratory values.

Why VO2 max matters

Cardiorespiratory fitness is more than a performance statistic. Large bodies of research associate higher cardiorespiratory fitness with better health outcomes and lower mortality risk. That is one reason organisations and researchers have argued that fitness deserves attention alongside other health indicators.

For runners and endurance athletes, VO2 max is also one component of performance. It helps describe aerobic capacity, but it does not determine race results by itself. Running economy, lactate threshold, pacing, durability, training consistency, strength, body composition, sleep, fuelling and experience all matter. Two runners with the same measured VO2 max can have very different race performances.

What is considered a good VO2 max?

Instead of using one universal threshold, it is more defensible to compare a score with a relevant reference group. The Fitness Registry and the Importance of Exercise National Database—known as FRIEND—has published reference standards from directly measured cardiopulmonary exercise tests in apparently healthy adults. Updated data included more than 22,000 tests and provided percentiles by age, sex and exercise mode.

The table below uses treadmill reference values from the updated FRIEND standards. It shows the 10th, 50th and 90th percentiles for men and women by decade. The 50th percentile can be thought of as the middle of that reference distribution: about half of the reference group was above it and half below. The 90th percentile represents a high level relative to that group. It is not a medical pass/fail boundary.

VO2 max reference values for men by age

Values are mL/kg/min and are treadmill percentiles from the updated FRIEND reference standards. They should not be substituted for clinical interpretation.

VO2 max reference values for women by age

Again, these are treadmill-based relative oxygen-uptake values in mL/kg/min. Cycle testing produces different reference distributions.

How should you read the table?

Suppose a 35-year-old man has a directly measured treadmill VO2peak of 44 mL/kg/min. In the FRIEND table for men aged 30–39, the median is 39.7 and the 90th percentile is 55.5. A value of 44 is therefore above the median reference value but below the 90th percentile. Describing it as “above average for that reference group” is more informative than applying a generic label such as excellent or poor.

Now suppose a 65-year-old woman has a treadmill VO2peak of 24 mL/kg/min. The median for women aged 60–69 in this dataset is 19.6, with the 90th percentile at 27.3. Her result sits above the median for that age/sex reference group even though 24 would look low beside the median for a woman in her twenties.

That is the central lesson: age context changes interpretation dramatically.

Why does VO2 max decline with age?

Average cardiorespiratory fitness declines across adulthood. Several physiological changes can contribute, including reductions in maximal heart rate, stroke volume, muscle mass, mitochondrial function and habitual physical activity. The rate of decline varies widely between individuals and can be influenced by training and health.

Aging does not make improvement impossible. A previously inactive 60-year-old can substantially improve aerobic fitness with appropriate training even though population reference values are lower than for people in their twenties. The useful comparison is often with your own previous fitness as well as an age-matched reference.

Why are male and female reference values different?

Population-level differences in haemoglobin concentration, heart size, stroke volume, body composition and muscle mass contribute to sex differences in measured relative VO2 values. This does not mean every man will have a higher VO2 max than every woman. The distributions overlap, and training status has a major effect.

Reference tables are descriptive. They show what was observed in a particular dataset, not what any individual “should” achieve. A highly trained woman may have a far higher VO2 max than a sedentary man of the same age.

Treadmill vs cycle VO2 max: why the test mode matters

The updated FRIEND data found that median VO2 values were higher for treadmill testing than cycle ergometry across age and sex groups. This is expected because treadmill exercise generally recruits a larger muscle mass and many people are more accustomed to walking or running than cycling at maximal effort.

If your score came from a bike test, do not compare it directly with a treadmill-only table and conclude that your fitness is poor. Use reference values matched to the test mode. The same principle applies when comparing a watch estimate with laboratory testing: the measurement method needs to stay consistent.

Measured VO2 max vs watch estimate

A smartwatch cannot directly analyse respiratory gases from your lungs. Instead it estimates aerobic fitness from inputs such as heart rate, pace, speed, age, sex and the manufacturer’s algorithm. Under suitable conditions the estimate can be useful, especially for observing trends within the same device.

However, several things can distort it: inaccurate wrist heart rate, heat, hills, fatigue, medication that alters heart rate, running economy, incomplete maximal effort, poor GPS data and changes in the algorithm itself. A watch value of 45 and a lab value of 45 are therefore not necessarily interchangeable.

For everyday fitness tracking, consistency is often more useful than chasing agreement with another device. If the same watch estimates 38, then 41, then 44 over several months while your running performance improves, that trend can be meaningful even if the absolute number is imperfect.

VO2 max vs VO2peak

Strictly, VO2max traditionally implies that a true maximum has been reached, often supported by physiological criteria such as a plateau in oxygen uptake despite increasing workload. In practice, a clear plateau is not always observed. Laboratories may therefore report VO2peak—the highest oxygen uptake achieved during the test.

For general readers, the terms are often used interchangeably online, but they are not always identical. If you are comparing published reference values with your test report, check how the laboratory defined the endpoint.

Relative vs absolute VO2

Relative VO2 is expressed per kilogram of body weight. Absolute VO2 is usually expressed in litres of oxygen per minute. Relative values make it easier to compare people of different sizes, particularly for weight-bearing sports such as running, but body weight can strongly influence the number.

If a person loses fat while maintaining aerobic capacity, relative VO2 can rise because the same absolute oxygen uptake is divided by a smaller body mass. Conversely, a muscular athlete can have a high absolute oxygen uptake but a lower relative value than expected because additional mass increases the denominator.

That is one reason modern reference research is also investigating body-composition-aware prediction equations rather than relying on one simple ratio for every body type.

Is a VO2 max of 30 good?

It depends. For a 25-year-old man, 30 mL/kg/min is below the FRIEND treadmill median of 46.5 and near the lower end of the distribution shown above. For a man in his seventies, 30 is around the high end of the reference distribution. For a woman aged 50–59, 30 is above the median and below the 90th percentile. The same number tells a different story in each context.

Is a VO2 max of 40 good?

A value of 40 mL/kg/min is close to the treadmill median for men aged 30–39, above the median for men aged 40–49, and high relative to older male age groups. For women, 40 is above the median in every adult decade shown and approaches or exceeds the high end in several age groups. Again, testing method matters.

Is a VO2 max of 50 good?

Fifty mL/kg/min represents high cardiorespiratory fitness for much of the general adult population. In the FRIEND treadmill standards it is above the median for men aged 20–29 and around the upper end for men in their forties; for women, 50 is around or above the 90th percentile even in the youngest adult group shown. Endurance athletes, however, can have substantially higher values, so “good” still depends on the population being compared.

Is a VO2 max of 60 good?

For the general population, 60 mL/kg/min is very high. It exceeds the 90th-percentile treadmill value shown for men aged 20–29 in the table and is well above the female 90th-percentile values. Elite endurance athletes can record much higher numbers, but elite-sport data should not be used as a general health standard.

How can you improve VO2 max?

Aerobic training can improve cardiorespiratory fitness, although the size of the response varies between people. A balanced programme normally includes a foundation of lower- to moderate-intensity aerobic work, gradually increasing training volume and some higher-intensity work when appropriate.

Intervals can be particularly useful for increasing aerobic capacity because they allow time near a high oxygen demand. That does not mean every session should be maximal. Too much high-intensity work can impair recovery, increase injury risk and reduce consistency. Most recreational athletes benefit from combining easier aerobic sessions with a smaller amount of harder work.

If you are new to exercise, returning after illness, have cardiovascular symptoms or have a medical condition, seek appropriate professional advice before attempting maximal testing or very hard interval training.

How quickly can VO2 max change?

Changes can occur over weeks to months, but the response depends on baseline fitness, programme design, genetics, training history, recovery and adherence. Beginners often have more room to improve than highly trained athletes. A single watch reading should not be used to judge progress because daily estimates can fluctuate.

Look for a trend across several weeks and pair it with performance indicators such as pace at a given heart rate, time-trial performance and perceived effort.

Can VO2 max be too low?

Low cardiorespiratory fitness is associated with poorer health outcomes at population level, but an online table cannot diagnose disease. A low test result could reflect low training status, incomplete effort, the testing modality, medication, body composition or an underlying health issue. If a formal test identifies unexpectedly low exercise capacity—especially alongside chest pain, breathlessness, dizziness or other symptoms—the result should be discussed with a healthcare professional.

Should you compare your VO2 max with an athlete?

Usually not if your goal is general health. Elite endurance athletes represent a highly selected group with years of training and favourable physiological traits. Comparing an ordinary recreational runner with an elite cyclist is no more useful than comparing a casual gym-goer’s one-repetition maximum with an Olympic weightlifter’s.

Use peers with similar age, sex and testing method, then use your own previous result as the most actionable comparison.

How to estimate VO2 max without a laboratory

Field tests can provide an estimate. One of the best-known is the 12-minute Cooper running test, where the distance covered in 12 minutes is entered into a prediction equation. We explain the protocol, formula, worked examples and limitations in How to Estimate Your VO2 Max From a Running Test.

Submaximal tests also exist, and many watches estimate VO2 max automatically. The key is to remember that an estimate is modelled from performance data rather than directly measured respiratory gases.

What is a MET and how does it relate?

A metabolic equivalent, or MET, is a way of expressing energy cost relative to resting metabolism. In clinical exercise testing, one MET is conventionally approximated as 3.5 mL O2/kg/min. A VO2 of 35 mL/kg/min therefore corresponds to about 10 METs using that convention.

This conversion is useful for understanding exercise capacity, although resting oxygen consumption is not exactly 3.5 for every individual. Again, population conventions should not be mistaken for perfectly individual measurements.

Frequently asked questions

What is the average VO2 max?

There is no single adult average. Median values differ substantially by age, sex and exercise mode. Use age- and sex-specific reference standards rather than one headline number.

Does VO2 max decline every year?

Population averages decline with age, but an individual can improve through training. The long-term trajectory is influenced by fitness habits, health and physiology.

Is Apple Watch VO2 max accurate?

It is an estimate, not direct gas analysis. It can be useful for within-device trends when conditions are suitable, but do not expect exact agreement with laboratory CPET.

Is Garmin VO2 max the same as laboratory VO2 max?

No. Garmin and other wearables use proprietary estimation algorithms. A lab CPET directly measures respiratory gases.

Can walking improve VO2 max?

Brisk walking can improve aerobic fitness, particularly in people who are less trained. As fitness rises, a stronger training stimulus may be required for further improvement.

Does weight loss increase VO2 max?

It can increase the relative mL/kg/min value if absolute oxygen uptake is maintained while body mass falls. That does not necessarily mean the heart and muscles increased their absolute oxygen-processing capacity by the same proportion.

What VO2 max do runners need?

There is no required number for recreational running. Race performance depends on multiple factors. Higher aerobic capacity is generally advantageous, but economy, threshold and training determine how much of that capacity you can use.

Can strength training increase VO2 max?

Traditional resistance training is not usually the most direct method for maximising VO2 max, although circuit-style training and improved overall conditioning may contribute. Aerobic and interval training are more specific.

Should I test VO2 max every month?

Formal maximal testing that frequently is unnecessary for most people. Field or wearable trends can be monitored more often, while lab tests are usually spaced according to a specific training or clinical reason.

Is a higher VO2 max always better?

Within normal health and performance contexts, higher cardiorespiratory fitness is generally favourable, but chasing a number at the expense of injury, recovery or overall health is not useful. It is one metric, not a complete health score.

How to use your number sensibly

First, identify how the number was obtained. Was it measured by laboratory CPET, predicted from a run, or estimated by a wearable? Second, compare it with a reference that matches the method as closely as possible. Third, consider your age and sex. Fourth, focus on changes over time using the same method.

If your goal is training, combine VO2 max with performance measures. If your goal is health, combine fitness with blood pressure, smoking status, sleep, activity, body composition and medical advice where appropriate. One impressive number cannot cancel every other risk factor, and one modest number does not define your health.

The bottom line

A good VO2 max is not one universal score. The most useful interpretation compares your result with people of similar age and sex tested in a similar way. The updated FRIEND standards show clearly that median aerobic fitness declines across age groups, differs between men and women and is affected by exercise mode.

If your result comes from a smartwatch or running test, treat it as an estimate and focus heavily on the trend. If you have a directly measured laboratory result, use the laboratory’s interpretation and relevant reference standards. Either way, the goal is not to collect the highest possible number—it is to build and maintain cardiorespiratory fitness that supports your health and the activities you want to do.

Sources and further reading

• Kaminsky et al. Updated Reference Standards for Cardiorespiratory Fitness Measured with Cardiopulmonary Exercise Testing: FRIEND
• Development of Global Reference Standards for Directly Measured Cardiorespiratory Fitness
• FRIEND reference equations incorporating estimated body composition