Key takeaways
VO2max is the maximum rate your body can take in and use oxygen, written in ml/kg/min
Inactive adults typically sit at 25 to 40 ml/kg/min and elite endurance athletes at 70 to 90+
Most untrained people improve VO2max by 10 to 20% within months of regular training
VO2max is the maximum rate at which your body can take in oxygen, deliver it to your muscles and use it, during all-out exercise. It is written in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min). A value of 50 means each kilogram of you can use 50 ml of oxygen every minute at your limit.
It is the most widely used single measure of aerobic or cardiorespiratory fitness — the fitness of your heart, lungs, blood and muscles working together.
Why it matters
- Performance: in endurance sports, VO2max sets the ceiling. Two other factors decide how close to that ceiling you can race — how high a fraction of it you can hold (your threshold) and how efficiently you move (your economy). See what limits VO2max.
- Health: low cardiorespiratory fitness is one of the strongest predictors of early death found in research, comparable to or stronger than smoking or diabetes in some studies. See VO2max and longevity.
How it is measured
In a lab, you run on a treadmill or ride a bike while wearing a mask that measures the oxygen you breathe in and the carbon dioxide you breathe out. Intensity rises every minute or two until you cannot continue. The highest oxygen uptake reached — ideally with a plateau even as the work keeps rising — is your VO2max.
On your wrist, watches estimate it. They don't measure oxygen; they look at how your heart rate relates to your pace or power during steady efforts, and combine that with your age, sex, weight and maximum heart rate. Running faster at the same heart rate implies a bigger engine. How good are those estimates? See how accurate is your watch's VO2max.
Typical values
| Group | Typical VO2max (ml/kg/min) |
|---|---|
| Inactive adults | 25–40 |
| Recreational runners | 45–55 |
| Well-trained club athletes | 55–70 |
| Elite endurance athletes | 70–90+ |
Values fall with age and are on average lower in women, mostly because of differences in haemoglobin and body composition. Compare yourself fairly with the VO2max chart by age and sex or read VO2max norms explained.
What changes it
- Training — regular easy aerobic volume plus hard intervals near your maximum, such as the Norwegian 4×4. Most untrained people improve 10–20% within months.
- Body weight — because it is per kilogram, losing or gaining weight moves the number even if your heart doesn't change. See why VO2max drops when you gain weight.
- Age — it declines slowly from your late twenties, faster after 60; training slows the decline. See VO2max and ageing.
- Genetics — they set your starting point and how much you respond. See why some people improve more.
- Inactivity and illness — fitness fades within weeks. See how fast you lose VO2max.
Frequently asked questions
What is VO2max in simple terms?
It is the maximum rate at which your body can take in oxygen, deliver it to your muscles and use it during all-out exercise. A value of 50 means each kilogram of you can use 50 ml of oxygen per minute at your limit.
What is a normal VO2max?
Inactive adults typically sit at 25 to 40 ml/kg/min, recreational runners at 45 to 55 and elite endurance athletes at 70 to 90 or more. Values fall with age and are on average lower in women.
Why is VO2max important?
It sets the ceiling for endurance performance, and low cardiorespiratory fitness is one of the strongest predictors of early death found in research, comparable to or stronger than smoking or diabetes in some studies.
Sources
- Bassett DR, Howley ET. Limiting factors for maximum oxygen uptake and determinants of endurance performance. Med Sci Sports Exerc, 2000.
- Ross R, et al. Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign. Circulation, 2016.