If you train for endurance, VO₂ max is one of the most honest numbers you can track. It cuts through how a session felt and tells you something concrete about your engine: how much oxygen your body can actually use when you push hard. Better still, you don’t need a lab to follow it, because a compatible Suunto watch estimates it from your everyday runs and walks.
At a glance
- VO₂ max is the maximum amount of oxygen your body can use during intense exercise, usually expressed in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min).
- It’s one of the most reliable indicators of aerobic fitness, cardiovascular endurance, and, to a point, your endurance potential.
- A higher VO₂ max is linked to better performance in running, cycling, trail running, triathlon, and cross-country skiing, and to a lower risk of cardiovascular disease.
- It varies widely from person to person with age, sex, training, and genetics.
- You can estimate it with a fitness test or a compatible sports watch.
- Many Suunto watches let you track how your VO₂ max changes over time.
What is VO₂ max?
VO₂ max, or maximal oxygen uptake, is the most oxygen your body can take in, transport, and use during hard physical effort. It’s measured in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min), and the higher it is, the more efficiently you produce energy during prolonged exercise.
That efficiency is why VO₂ max matters so much in endurance sports: running, trail running, cycling, triathlon, cross-country skiing, and hiking all draw heavily on it.
Why VO₂ max matters
Knowing your VO₂ max gives you an objective measure of fitness that goes beyond how a workout felt. Practically, it lets you:
- Assess your fitness level: it’s a widely recognised marker of cardiovascular fitness and endurance capacity.
- Track your progress: watching it shift over weeks or months shows whether your training is actually working.
- Fine-tune your training: paired with heart rate data, it helps set training zones that match your current fitness.
- Understand your health: a higher VO₂ max is generally associated with lower cardiovascular risk and greater longevity.
How to calculate VO₂ max
There are a few ways to measure or estimate VO₂ max, trading accuracy against convenience.
1. Laboratory exercise testing
The gold standard is a maximal exercise test with respiratory gas analysis in a lab. Intensity ramps up while you breathe through a mask, and your oxygen intake and carbon dioxide output are measured in real time. It’s direct and highly accurate, but it needs specialist equipment and supervision.
2. Field tests
Several field tests estimate VO₂ max without lab kit, using the speed or distance you can sustain. Common protocols include the Cooper Test, the Half Cooper Test, the VAMEVAL Test, and the Léger-Boucher Test.
3. Calculators and indirect estimates
Some apps and training platforms estimate VO₂ max from your performance, pace, speed, or heart rate. They’re less precise than a lab test, but they’re well suited to tracking trends over time.
How to measure VO₂ max on a sports watch
Many sports watches now estimate VO₂ max automatically, drawing on your heart rate, pace or speed, exercise duration, GPS data, and training history.
Suunto estimates VO₂ max, shown as your fitness level, from data collected during outdoor running and walking. The watch reads your heart rate response to sustained effort alongside pace and movement data to gauge your aerobic fitness. Record a run or walk of at least 15 minutes and the algorithm has enough to work with; keep training, and the estimate updates to track your endurance trend.
On earlier models such as Suunto 9 and Suunto 7, it appears under Fitness level.
On newer devices such as the Suunto Vertical 2, Suunto Race 2, Suunto Run, Suunto Race S, Suunto Ocean, Suunto Race, Suunto Vertical, and Suunto 9 Peak Pro, it lives in the Progress view, and you can also see it in the Suunto app.
It isn’t a lab measurement, but as a practical indicator of how your cardiovascular fitness is trending, it’s hard to beat for everyday training.
What’s a good VO₂ max?
It depends on your age, sex, and fitness level. As a rough guide for healthy adults:
- Under 30 ml/kg/min: Low
- 30–40 ml/kg/min: Average
- 40–45 ml/kg/min: Good
- 45–50 ml/kg/min: Excellent
- 50+ ml/kg/min: Superior (highly trained)
These are general reference points, though. To judge your own score fairly, compare it with people of the same age and sex, which is exactly what the charts below let you do.
VO₂ max charts by age for men and women
VO₂ max declines naturally with age and differs between men and women. Use the reference values below to compare your estimate with others of the same age and sex. Treat them as general guidelines rather than diagnostic criteria; individual results vary with training history, genetics, health, and testing method.
Men’s VO₂ max chart (ml/kg/min)
|
Age
|
Poor
|
Fair
|
Average
|
Good
|
Excellent
|
Superior
|
|
20–29
|
<33
|
33–36
|
37–41
|
42–45
|
46–52
|
>52
|
|
30–39
|
<31
|
31–34
|
35–39
|
40–43
|
44–50
|
>50
|
|
40–49
|
<28
|
28–32
|
33–36
|
37–40
|
41–46
|
>46
|
|
50–59
|
<25
|
25–29
|
30–33
|
34–38
|
39–43
|
>43
|
|
60–69
|
<22
|
22–25
|
26–30
|
31–34
|
35–41
|
>41
|
Women’s VO₂ max chart (ml/kg/min)
|
Age
|
Poor
|
Fair
|
Average
|
Good
|
Excellent
|
Superior
|
|
20–29
|
<23
|
23–29
|
30–35
|
36–41
|
42–46
|
>46
|
|
30–39
|
<20
|
20–27
|
28–33
|
34–39
|
40–44
|
>44
|
|
40–49
|
<17
|
17–24
|
25–31
|
32–35
|
36–41
|
>41
|
|
50–59
|
<15
|
15–21
|
22–28
|
29–34
|
35–39
|
>39
|
|
60–69
|
<13
|
13–20
|
21–24
|
25–30
|
31–35
|
>35
|
*Reference ranges are adapted from the normative cardiorespiratory fitness classifications in the American College of Sports Medicine (ACSM) Guidelines for Exercise Testing and Prescription (11th edition).
On average, women tend to have lower VO₂ max values than men, largely due to physiological differences in muscle mass, blood volume, and haemoglobin levels.
How to interpret your VO₂ max result
The same number can mean very different things depending on who you are. A VO₂ max of 35 ml/kg/min might be average for a 30-year-old man, good for a 40-year-old woman, and excellent for someone over 60.
For most recreational athletes, watching how your own VO₂ max moves over time is far more useful than chasing elite figures. Steady improvement, even a modest one, is usually a sign your training is doing its job.
What affects VO₂ max
VO₂ max is the product of several systems working together:
- Heart: cardiac output sets how much oxygen reaches your muscles.
- Lungs: they load oxygen into your blood and clear carbon dioxide.
- Oxygen transport: haemoglobin carries that oxygen around the body.
- Muscles: they have to use the available oxygen efficiently.
- Genetics: a meaningful share of your potential is inherited.
- Age: without regular training, VO₂ max gradually declines.
The benefits of a higher VO₂ max
Raising your VO₂ max pays off in several ways:
- Better performance: you can hold a higher intensity for longer.
- Greater endurance: fatigue arrives later in prolonged efforts.
- Faster recovery: a more efficient cardiovascular system helps you bounce back.
- Healthier heart: better aerobic fitness is tied to lower cardiovascular risk and all-cause mortality.
- An edge across sports: running, trail, cycling, triathlon, cross-country skiing, and hiking all reward it.
How to improve VO₂ max
Lifting your VO₂ max comes down to consistent training and smart recovery. The strategies that move the needle most:
1. Add high-intensity intervals
Interval and HIIT sessions are among the most effective ways to raise VO₂ max. A classic example: five reps of 3 minutes at high intensity, with 2 minutes of active recovery between each.
2. Build a strong aerobic base
Longer, low-to-moderate sessions improve the underlying efficiency of your aerobic system, the foundation everything else sits on.
3. Vary your intensity
Rotating easy endurance, threshold work, and intervals drives complementary adaptations rather than hammering the same system.
4. Stay consistent
Long-term consistency beats the occasional brutal workout every time.
5. Protect recovery
Quality sleep, solid nutrition, good hydration, and planned rest days are what let fitness build while keeping injury risk down.
VO₂ max vs VMA: what’s the difference?
VMA (maximum aerobic speed) is the running speed at which you hit your VO₂ max during a progressive test. In other words, VO₂ max measures your capacity to use oxygen, while VMA measures the speed at which that ceiling is reached.
Two runners can share a similar VO₂ max yet post different VMA values, depending on running economy, technique, and experience.
|
Profile
|
VO₂ max
|
VMA
|
|
Beginner
|
40 ml/kg/min
|
12 km/h
|
|
Regular runner
|
50 ml/kg/min
|
15 km/h
|
|
Experienced runner
|
60 ml/kg/min
|
18 km/h
|
Improving VO₂ max generally lifts your VMA too, but dedicated speed and technique work is still what turns capacity into race pace.
VO₂ max FAQ
1. What’s the average VO₂ max?
Roughly 35–45 ml/kg/min for men and 25–35 ml/kg/min for women, with about 30–40 ml/kg/min considered average fitness for most adults.
2. What’s a good VO₂ max for men?
Generally around 40–45 ml/kg/min, with 45–50 excellent and above 50 superior, depending on age.
3. What’s a good VO₂ max for women?
Generally around 32–40 ml/kg/min, with 40–45 excellent and above 45 superior, depending on age.
4. Does VO₂ max decline with age?
Yes. It gradually falls as you get older, but regular exercise can slow that decline significantly.
5. Can you improve VO₂ max after 50?
Absolutely. Meaningful gains are still very achievable with an appropriate, progressive, and consistent training program.
6. Do sports watches really measure VO₂ max?
Not directly, the way a lab does. They use mathematical models based on heart rate, speed, workout duration, and training history to estimate your fitness level.
7. What’s the difference between VO₂ max and heart rate?
Heart rate shows how your body responds to exercise in the moment, while VO₂ max estimates your maximum capacity to use oxygen. They complement each other: heart rate tracks intensity in real time; VO₂ max gives the longer-term view of your aerobic fitness.
The takeaway
VO₂ max is one of the clearest measures of aerobic fitness, and it’s most useful when you follow your own trend rather than compare yourself to elites. With a compatible Suunto watch estimating it from your everyday training, you can see the effect of your work over time and adjust with confidence.
Explore Suunto watches that track VO₂ max and keep your fitness moving in the right direction.
