What's a Good VO₂ Max for Your Age?

If you wear an Apple Watch, you probably have a VO₂ max number already, whether you asked for one or not. It’s the Cardio Fitness figure in the Health app. The questions that follow tend to be the same: is mine good for my age, can I trust it, and what actually raises it?

This guide takes them in order. The VO₂ max by age chart comes from the 2022 update of FRIEND, a US registry of more than 22,000 lab exercise tests. Then we look at how the Watch arrives at its estimate and how far off it can be, what the long-term health research does and doesn’t show, and a training week built around the kind of session the studies point to.

One note before the numbers: this is general information, not medical advice. If your Watch says your cardio fitness is low, or you have a heart condition and want to start hard training, talk to your doctor first.

What is VO₂ max?

VO₂ max is the most oxygen your body can take in and use in a minute when you’re working as hard as you can. It depends on the whole chain, from your lungs and heart to your blood and the muscles doing the work, which is why Apple’s white paper on VO₂ max calls it a good overall indicator of cardiorespiratory fitness.

It’s measured in millilitres of oxygen per kilogram of body weight per minute, written ml/kg/min. A 70 kg runner with a VO₂ max of 45 is using about 3.15 litres of oxygen a minute at the top of a test. Dividing by body weight lets people of different sizes be compared, and it also means the number shifts when your weight does, even if your heart and lungs haven’t changed.

In a lab, it’s measured with a cardiopulmonary exercise test. You run on a treadmill or ride a bike while the effort rises step by step, wearing a mask that measures the air you breathe in and out, until you can’t go on. The highest oxygen uptake you reach is the result. Labs often call it VO₂ peak, since there’s no guarantee a true maximum was reached. Most other methods, your Watch included, estimate it from effort below your maximum. Some of the health studies further down use METs instead: one MET is about 3.5 ml/kg/min.

VO₂ max by age chart

Our reference values come from the Fitness Registry and the Importance of Exercise National Database, known as FRIEND. The 2022 update, by Leonard Kaminsky and colleagues in Mayo Clinic Proceedings, pooled 22,379 tests from 34 US labs, done between 1968 and March 2021 on apparently healthy adults aged 20 to 89, with oxygen measured directly. It reports percentiles for each decade of age, separately for men and women and for treadmill and bike tests.

The tables below are the treadmill values from the paper’s Table 3 (16,278 treadmill tests), copied exactly. The 50th percentile is the middle: half the people of that age and sex scored higher, half lower. The paper gives every tenth percentile, and we’ve kept five. All values are in ml/kg/min.

VO₂ max chart for men

Age	10th	20th	50th	80th	90th
20–29	28.6	35.2	46.5	54.5	58.6
30–39	24.9	29.8	39.7	50.0	55.5
40–49	22.1	26.7	35.3	45.2	50.8
50–59	18.6	22.2	29.2	38.3	43.4
60–69	15.8	18.5	24.6	32.0	37.1
70–79	13.6	15.9	20.6	25.9	29.4
80–89	12.9	14.8	17.6	21.4	22.8

VO₂ max chart for women

Age	10th	20th	50th	80th	90th
20–29	22.5	27.2	36.6	44.8	49.0
30–39	18.6	21.9	28.3	37.0	42.1
40–49	17.2	19.7	25.7	33.0	37.8
50–59	16.5	18.5	22.9	28.4	32.4
60–69	13.4	15.4	19.6	24.3	27.3
70–79	12.3	14.0	17.2	20.8	22.8
80–89	11.4	12.6	15.4	18.4	20.8

To read it, find your age row and see where your number lands. For women aged 40 to 49, a lab result of 33.0 sits at the 80th percentile: higher than about 8 in 10 women that age in the registry.

A few things stand out in the paper:

• The middle value falls with each decade. Averaged over six decades, treadmill values dropped by about 4.0 ml/kg/min, or 13.5 percent, per decade. These are different people at different ages rather than the same people followed for years, so the chart shows what’s typical at each age, not a rate you’re bound to follow.
• Men’s values are higher at every age. On the treadmill they were 26 percent (6.6 ml/kg/min) higher overall.
• Bike tests come out lower. Treadmill results averaged 22 percent (4.5 ml/kg/min) higher than cycle results, so if your lab test was on a bike, compare it with the paper’s cycle table instead.
• Older charts run higher. The 2022 treadmill standards are 1.5 to 4.6 ml/kg/min lower than the first FRIEND standards from 2015. The authors think that reflects a bigger, more representative sample rather than people getting less fit.

The limits are worth knowing too. FRIEND is US data, and the authors say to apply it cautiously elsewhere. It excluded people with diagnosed heart disease or COPD, but “apparently healthy” still included people with conditions such as diabetes and obesity. Labs used different equipment and protocols, and the groups aged 80 to 89 are small.

So what’s a good VO₂ max for your age?

The paper doesn’t draw a line called “good”. It gives percentiles, and we’d read them like this. At or above the 50th percentile, you’re fitter than most people your age and sex who were tested. The 80th and 90th percentile columns show what very fit looks like at each age. The bottom fifth is the part to take seriously: Apple sets its low cardio fitness alert for people aged 20 to 59 at roughly that level (more on that below), and in the long-term studies further down, the least fit groups carried the highest risk.

What your Apple Watch cardio fitness number means

How the Watch estimates VO₂ max

Cardio Fitness is Apple’s estimate of your VO₂ max, in the same ml/kg/min. The Watch doesn’t measure oxygen. According to Apple’s support page, it measures how hard your heart is working during an Outdoor Walk, Outdoor Run or Hiking workout, using the heart and motion sensors, and takes into account your age, sex, weight, height and any medications you’ve listed that might affect your heart rate. Indoor workouts, including ones on gym equipment, don’t count.

The white paper spells out the conditions: relatively flat ground (a grade of less than 5 percent up or down), adequate GPS and heart-rate signal, and enough effort, roughly an increase of 30 percent of the range between your resting and maximum heart rate. Your first qualifying workout won’t produce a number. Apple says it can take at least 24 hours of wearing the Watch, followed by several outdoor walks, runs or hikes, before the first estimate appears. It needs an Apple Watch Series 3 or later and covers values from 14 to 65 ml/kg/min.

The estimate is a prediction from effort below your maximum, so you don’t have to go all out for it. The algorithm still needs a sense of your maximum heart rate, though, which is why medications that lower it matter.

Apple’s Cardio Fitness levels by age and sex

The Health app sorts your estimate into one of four levels for your age and sex: Low, Below Average, Above Average or High, according to the Apple Watch User Guide. Levels are available from age 20. Apple doesn’t print the cut-offs on its support pages; you’ll find them in the app. In Health, go to Browse, then Heart, then Cardio Fitness, and tap Show All Cardio Fitness Levels.

The white paper does explain where the low alert sits. For people aged 20 to 59, it’s the lowest fifth for their age and sex in the original 2015 FRIEND standards, whose treadmill values ran higher than the 2022 chart above. From 60 up, Apple uses fixed thresholds of 18 ml/kg/min for men and 15 for women, based on research on the fitness needed to live independently in old age.

If you turn on Cardio Fitness Notifications (in the Watch app on your iPhone: My Watch, then Apps, then Heart), you get an alert when your level falls in the Low range, and another every four months if it stays there. Apple built the alert for estimates that are consistently and confidently low enough to suggest a risk of long-term health problems or a current limit on daily activities. If you get one, book a check-up with your doctor before starting a hard training block, and take the trend from the Health app with you.

How accurate is it?

Apple validated the algorithm it introduced with watchOS 7 on 221 people who were kept out of its development. On average, the Watch’s estimate came out 1.4 ml/kg/min higher than their lab reference, with a standard deviation of 4.7 around that, and estimates taken at least 28 days apart agreed well (an intraclass correlation of 0.86). The reference itself wasn’t an all-out test, though. Apple projected each person’s heart-rate and oxygen readings from submaximal lab tests out to their age-predicted maximum heart rate.

Independent comparisons with all-out treadmill tests and gas analysis have found bigger gaps. Researchers at University College Dublin found the Watch read 6.07 ml/kg/min low on average in 28 adults wearing mostly Series 9 and Ultra 2 watches, and 6.25 low in 35 adults wearing the Series 10, with an average error of about 13 percent in both. Both groups were mostly young and very fit, and in the Series 10 study the gap was largest in the fittest people: 7.79 ml/kg/min for those at or above the 80th percentile, against 2.41 for the rest. A smaller German study of the Series 7, tested on a bike, also found the Watch read lower on average, and concluded it tends to overestimate people with low fitness and underestimate people with excellent fitness.

Why the Watch and a lab disagree

• It’s a prediction from heart rate. The Watch infers VO₂ max from how your heart responds at a given pace. A lab measures the oxygen itself.
• It was calibrated against a projection. Apple’s reference came from submaximal tests, not all-out efforts.
• Labs disagree with each other too. Treadmill tests read about 22 percent higher than bike tests in FRIEND, and protocols vary from lab to lab.
• Anything that raises your heart rate at a given pace can pull the estimate down. Apple lists dehydration, caffeine, extreme heat and a recent move to high altitude, as well as extra work the Watch can’t see, such as a heavy backpack, carrying a child or running on sand. Pushing a stroller can make estimates less available or less accurate.
• Wrong details skew it. An incorrect age, sex or weight in the Health app can make estimates consistently off, and pregnancy can too.
• Heart-rate medication matters. If you take a drug that limits heart rate, such as a beta blocker, and don’t add it in Health Details, the Watch will read high. In Apple’s validation group, the average error for people on these drugs fell from 11.8 to 1.6 ml/kg/min once the setting was right. Conditions that stop your heart rate rising normally, arrhythmias and pacemakers can also throw it off.

The practical takeaway: use the Watch to follow your own trend, from similar flat outdoor workouts, and don’t read a single number as if it came from a lab. Apple’s data puts the typical spread between one person’s readings at about 1.2 ml/kg/min, so a one-point dip means very little. Apple says accuracy improves with frequent outdoor walks or runs, higher effort during them, and wearing the Watch through the day.

Why VO₂ max matters for long-term health

Low cardiorespiratory fitness turns up as a warning sign again and again in long-term studies. In 2016 the American Heart Association published a scientific statement arguing that fitness should be assessed in clinical practice as a vital sign, pointing to its links with cardiovascular disease, death from any cause and deaths from various cancers.

Two large studies give a sense of scale:

• Mandsager and colleagues (2018) followed 122,007 people sent for a treadmill test at the Cleveland Clinic, most often to check for heart disease or symptoms, for a median of 8.4 years. Compared with the fittest 2.3 percent for their age and sex, those in the bottom quarter had about five times the risk of dying during follow-up (adjusted hazard ratio 5.04). Being below average rather than above average carried a hazard ratio of 1.41, the same as smoking and close to diabetes (1.40) in the same analysis, and the authors saw no upper limit to the benefit of fitness.
• Kokkinos and colleagues (2022) studied 750,302 US veterans aged 30 to 95 (45,232 of them women) over a median of 10.2 years. The link between fitness and risk of death was graded across ages, sexes and races. The least fit (20th percentile) had about four times the risk of the most fit (hazard ratio 4.09), and extremely high fitness showed no increase in risk.

These are associations. Both studies graded fitness by the METs people reached on a standard exercise treadmill test, and neither can prove that raising your own VO₂ max will add a particular number of years. Mandsager’s team say so directly: their data can’t separate how much fitness lowers risk from how much being fit marks out people who were at lower risk to begin with. What the research does show consistently is that the least fit groups carry the highest risk, and that higher fitness hasn’t been linked with higher risk, even at the very top.

How to increase your VO₂ max

Apple’s support page puts it in one line: most people can improve their VO₂ max by increasing the intensity and frequency of their cardio. The research fills in the detail.

Build a base of easy running

Steady, continuous training raises VO₂ max on its own. In a meta-analysis of 28 controlled trials in 723 healthy adults aged 18 to 45, who started at an average of 40.8 ml/kg/min, Milanović and colleagues found continuous endurance training raised VO₂ max by about 4.9 ml/kg/min compared with people who didn’t train. And when Seiler reviewed how nationally and internationally competitive endurance athletes train, the pattern was consistent: about 80 percent of sessions at low intensity, and about 20 percent built around hard work such as intervals near 90 percent of VO₂ max.

Easy means conversational: you could talk in full sentences. We’d make it most of your week, because it builds aerobic volume without much fatigue, and that leaves you fresh enough to make the hard session properly hard. Our zone 2 training guide covers how to pace it.

Add one session of hard intervals

The best-known study here is Jan Helgerud’s 2007 trial in Norway. Forty healthy, moderately trained men trained three days a week for eight weeks in one of four ways, all matched for total work: long slow running at 70 percent of maximum heart rate, running at lactate threshold (85 percent), 15-second intervals, or 4 × 4 minutes at 90 to 95 percent of maximum heart rate with 3 minutes of active recovery at 70 percent. Both interval groups raised VO₂ max significantly more than the steady groups. In the 4 × 4 group it went from 55.5 to 60.4 ml/kg/min.

The meta-analysis points the same way, with a smaller edge. HIIT raised VO₂ max by about 5.5 ml/kg/min against people who didn’t train, and by about 1.2 ml/kg/min more than continuous training when the two were compared directly. So intervals help, but as a top-up on the base rather than a replacement for it. Helgerud’s groups each did three sessions a week of a single type of training. In a normal week that also holds easy runs, a long run and maybe some lifting, we’d start with one.

A 4 × 4 session looks like this: 10 minutes easy to warm up, four 4-minute efforts at 90 to 95 percent of your maximum heart rate with 3 minutes of easy jogging between, then 10 minutes easy. If you don’t know your maximum heart rate, go by feel: hard enough that you can only get a few words out by the end of each rep, but even enough that the fourth rep is as strong as the first.

Cinder’s Hybrid Run and Lift plan uses a close cousin in its Interval Run: a 10-minute warm-up, 6 × 3 minutes hard with 90 seconds easy between, and a 10-minute cool-down. The rest of that plan is in our hybrid training plan.

Hard intervals are meant to take your heart rate close to its maximum. If you have a heart condition, take medication that affects your heart rate, are pregnant, or have been inactive for a long time, check with your doctor before adding them. Stop and get checked if you feel chest pain, feel faint, or get breathless out of proportion to the effort.

How fast VO₂ max improves

In the studies, average gains are a few ml/kg/min, and people differ a lot:

• Adults aged 18 to 45: about 5 ml/kg/min on average against people who didn’t train in the meta-analysis above, and 55.5 to 60.4 ml/kg/min over eight weeks of 4 × 4 in Helgerud’s trial.
• Older adults: in a meta-analysis of 41 trials with 2,102 sedentary older adults (groups averaging 60 or older), aerobic training raised VO₂ max by 3.78 ml/kg/min on average, about 16 percent, compared with controls, with larger gains in programmes longer than 20 weeks.
• Individual differences: in the HERITAGE Family Study, 481 sedentary adults did the same 20-week programme. Some gained little or nothing while others gained a lot, and the researchers estimated that up to 47 percent of the variation in response was heritable.

A sample week to raise VO₂ max

This is our suggestion, not a protocol from a study: one interval session, one long easy run, and easy running in between. It assumes you already run three or four times a week without pain.

Day	Session	What to do
Monday	Rest	Or a strength session
Tuesday	Intervals	10 min easy, 4 × 4 min hard with 3 min easy jogging between, 10 min easy
Wednesday	Easy run	30 to 45 min, conversational
Thursday	Rest	Or a strength session
Friday	Easy run	30 to 45 min, conversational
Saturday	Long run	The longest run of your week, all at an easy pace
Sunday	Rest	A walk is fine

New to intervals? Start with three reps and add the fourth after a couple of weeks. Keep the interval day and the long run at least a day apart. Give the block at least eight weeks, the length of Helgerud’s trial, before you judge it, and compare Watch readings from similar flat outdoor routes in similar weather.

If you use Cinder, the workout tracker we make, it reads the VO₂ max your Watch saves to Apple Health and uses it in the app’s biological age estimate. Cinder averages your last seven daily readings, compares that with an expected value for your age and sex, and turns the gap into years: 0.35 years younger for every ml/kg/min above it, or older for every one below, capped at six years either way. The app calls the result an estimate, “a heuristic built from well-known associations, not a medical measurement.” It also notices when your runs from the past two weeks (at least three of them) sat within a few percent of the same pace, with an insight titled “Your runs all look the same” that suggests swapping one for a fartlek of 8 × 1 minute surges.

VO₂ max FAQ

Is 40 a good VO₂ max?

It depends on your age and sex. In the FRIEND treadmill data, 40 is exactly the 30th percentile for men aged 20 to 29, just above the middle (39.7) for men in their 30s, and above the 80th percentile for men in their 50s. For women, 40 sits above the 60th percentile at 20 to 29, above the 80th in the 30s, and above the 90th from 40 onwards. If your 40 comes from an Apple Watch rather than a lab, remember that independent tests found the Watch tends to read low in very fit people.

What’s the average VO₂ max by age?

In the FRIEND treadmill data, the average (mean) was 45.2 ml/kg/min for men and 36.3 for women aged 20 to 29, 35.8 and 26.6 at 40 to 49, and 25.4 and 20.0 at 60 to 69. The middle values (50th percentile) for every decade are in the chart above.

Can you increase VO₂ max after 50?

Yes. The HIIT meta-analysis above only included adults aged 18 to 45, but trials in older people show clear gains too. The meta-analysis of 41 trials in sedentary older adults (groups averaging 60 or older) found an average rise of 3.78 ml/kg/min, about 16 percent, against controls. A later analysis of sedentary adults averaging 67 years found the biggest average gains at 66 to 73 percent of heart-rate reserve, 40 to 50 minutes a session, three or four days a week, over 30 to 40 weeks. Check with your doctor before you start, especially before hard intervals.

How accurate is Apple Watch VO₂ max?

We’d use it to follow your own trend, not as a stand-in for a lab test. Apple reports that repeat readings are consistent and that its estimates averaged 1.4 ml/kg/min above a submaximal lab reference. Independent studies that compared it with all-out treadmill tests found it read about 6 ml/kg/min low on average, with an average error of about 13 percent, mostly in young, fit people. Keeping your age, weight and medications up to date in the Health app helps.

Why did my Apple Watch VO₂ max drop?

Sometimes it’s real: Apple’s white paper notes that falls in VO₂ max have been reported after as little as two to three weeks of reduced activity. But check the usual suspects first: a very hot day, dehydration, caffeine, a recent trip to altitude, a heavy pack, soft ground, or out-of-date details in the Health app. A single low reading means little. A slide over several weeks with no obvious cause is worth a look, and worth mentioning to your doctor if it comes with breathlessness or tiredness you can’t explain.

How we made this

The chart is Table 3 of Kaminsky and colleagues (2022), using the treadmill values and the paper’s main effort criterion (a respiratory exchange ratio of at least 1.0). We copied it number for number from the paper’s full text and checked it against a second extraction; the averages come from the paper’s Table 2. Apple’s figures come from its support pages and its May 2021 white paper on estimating VO₂ max with Apple Watch. Every other study figure comes from the study’s full text or its PubMed abstract, and we left out numbers we couldn’t check against a primary source. The Cinder details come from the app’s source code. The sample week is our own suggestion. The photo is from Wikimedia Commons.

References

• Kaminsky LA, Arena R, Myers J, Peterman JE, Bonikowske AR, Harber MP, Medina Inojosa JR, Lavie CJ, Squires RW. 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 Clinic Proceedings. 2022;97(2):285-293.
• Apple. Using Apple Watch to Estimate Cardio Fitness with VO2 max. White paper, May 2021.
• Apple Support. Track your cardio fitness levels.
• Apple Watch User Guide. Monitor your heart health on Apple Watch.
• Lambe R, O’Grady B, Baldwin M, Doherty C. Investigating the accuracy of Apple Watch VO2 max measurements: A validation study. PLOS One. 2025;20(5):e0323741.
• Lambe R, Schumann M, Donnelly L, Hamilton S, Lally S, Rafter E, O’Reilly S, White T, Doherty C. Accuracy of VO2 max Estimates From Apple Watch Series 10. Mayo Clinic Proceedings: Digital Health. 2026;4(2):100357.
• Caserman P, Yum S, Göbel S, Reif A, Matura S. Assessing the Accuracy of Smartwatch-Based Estimation of Maximum Oxygen Uptake Using the Apple Watch Series 7: Validation Study. JMIR Biomedical Engineering. 2024;9:e59459.
• Ross R, Blair SN, Arena R, et al. Importance of Assessing Cardiorespiratory Fitness in Clinical Practice: A Case for Fitness as a Clinical Vital Sign: A Scientific Statement From the American Heart Association. Circulation. 2016;134(24):e653-e699.
• Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing. JAMA Network Open. 2018;1(6):e183605.
• Kokkinos P, Faselis C, Samuel IBH, et al. Cardiorespiratory Fitness and Mortality Risk Across the Spectra of Age, Race, and Sex. Journal of the American College of Cardiology. 2022;80(6):598-609.
• Helgerud J, Høydal K, Wang E, et al. Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine & Science in Sports & Exercise. 2007;39(4):665-671.
• Milanović Z, Sporiš G, Weston M. Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled Trials. Sports Medicine. 2015;45(10):1469-1481.
• Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance. 2010;5(3):276-291.
• Huang G, Gibson CA, Tran ZV, Osness WH. Controlled endurance exercise training and VO2max changes in older adults: a meta-analysis. Preventive Cardiology. 2005;8(4):217-225.
• Huang G, Wang R, Chen P, Huang SC, Donnelly JE, Mehlferber JP. Dose-response relationship of cardiorespiratory fitness adaptation to controlled endurance training in sedentary older adults. European Journal of Preventive Cardiology. 2016;23(5):518-529.
• Bouchard C, An P, Rice T, et al. Familial aggregation of VO2max response to exercise training: results from the HERITAGE Family Study. Journal of Applied Physiology. 1999;87(3):1003-1008.