What Is a Good VO2 Max for My Age and Sex?

I’ve checked my VO2 max regularly for years. Before our daughter was born, I was training deliberately to push it higher, doing structured intervals a couple of times a week and watching the number tick up season over season. It’s lower now. Not because anything went wrong, but because the last year has had different priorities: less sleep, less consistent training time, a lot more of my energy going somewhere else entirely. The first time I saw the drop on my watch, I caught myself reading it as a loss. It isn’t one. It’s just what happens when the hours you used to spend building a number get spent on something else for a while. That reframe is the actual point of this piece: a “good” VO2 max isn’t a fixed target, it’s a number that only means something next to your age, your sex, and your own history.

Quick digest

• VO2 max measures the most oxygen your body can use per minute during maximal effort (in ml per kg of body weight per minute). Researchers rank it among the strongest predictors of long-term health they’ve found.
• “Good” only exists relative to your age and sex. The same raw number can sit below average for a fit 25-year-old and comfortably above average for a fit 65-year-old.
• Men typically post VO2 max scores 20–30% higher than women at the same age, mostly because of heart size, blood volume, and hemoglobin, not effort or training quality.
• VO2 max drops by roughly 10% per decade after 30 for the average adult, but people who keep training through those decades see a decline closer to half that.
• Menopause on its own doesn’t appear to crash VO2 max in women who stay active. The studies that separate hormones from activity level find the decline tracks age and training, not estrogen alone.

What VO2 max actually measures

VO2 max is the maximum volume of oxygen your body can take in, transport, and use in one minute of maximal effort, expressed relative to your body weight (ml/kg/min). It’s a ceiling: the point where your heart, lungs, blood, and muscles are working together at their combined limit and can’t deliver or use oxygen any faster, no matter how hard you push.

The gold-standard way to measure it is a lab test called cardiopulmonary exercise testing (CPET), where you run or cycle to exhaustion while breathing through a mask that measures exactly how much oxygen you’re using. Most people never do this test. What you see on a Garmin or Apple Watch is an estimate, built from your pace, heart rate, and (on some devices) heart rate variability during runs, and it can be off by several points in either direction. That’s a big enough topic on its own that we’ve written about it separately; the short version is that wearable estimates are a reasonable trend line, not a lab result, so don’t treat a single reading as gospel.

What makes VO2 max worth caring about isn’t really the running-performance angle. A 2016 American Heart Association scientific statement went as far as recommending it be treated as a clinical vital sign alongside blood pressure and heart rate, because low cardiorespiratory fitness predicts cardiovascular disease and all-cause mortality more strongly than smoking, high blood pressure, or high cholesterol (Ross et al., 2016). A 2018 study of over 122,000 adults who underwent treadmill testing found that cardiorespiratory fitness kept predicting survival all the way up the scale, with no ceiling: the fittest group in the study, people scoring two standard deviations above average for their age and sex, had the lowest mortality risk of anyone measured, including people on standard heart medications (Mandsager et al., 2018). That’s the real reason this number is worth tracking over your life, not because it makes you faster on a Saturday long run, but because it’s one of the more honest snapshots of how your whole cardiovascular system is holding up.

What counts as “good,” by age and sex

The most widely used reference data for U.S. adults comes from the Fitness Registry and the Importance of Exercise National Database (FRIEND), built from thousands of lab-measured, maximal treadmill tests (Kaminsky et al., 2015). It breaks VO2 max into percentiles by decade, for men and women separately. The table below shows the 25th, 50th (median), and 75th percentile for each age bracket, rounded to numbers you can actually picture.

Men — VO2 max (ml/kg/min)

Women — VO2 max (ml/kg/min)

A few notes on reading this. If you’re 18 or 19, there isn’t a separate reference bracket for you; most datasets, including FRIEND, start at 20 because aerobic capacity is close to its lifetime peak from the late teens through the late twenties, so the 20–29 column is the practical comparison point unless you’re a competitive junior athlete being tracked against sport-specific norms.

Sitting at the 50th percentile means you’re squarely average for your age and sex, not a problem, just the midpoint. Above the 75th percentile is where most people would comfortably call their fitness “good”: you’re outperforming three-quarters of your peer group. Below the 25th percentile is worth paying attention to, less as a verdict and more as a signal that structured aerobic training would likely move the number meaningfully, since that’s exactly where the biggest, fastest gains tend to happen.

One more thing worth sitting with: a 50-year-old man scoring 40 ml/kg/min is in genuinely excellent shape for his age, sitting above his 75th percentile, while the same 40 would be roughly average for a 25-year-old man. The number by itself tells you almost nothing. The number next to your age and sex tells you where you actually stand.

Why the numbers differ so much by sex

At every age, men’s VO2 max scores run meaningfully higher than women’s, typically 20–30% at the same age and training level. This isn’t about effort, motivation, or how seriously someone trains. It comes down to a handful of specific physiological differences that show up even when researchers match men and women for age, body size, and fitness level (Santisteban et al., 2022).

The biggest factor is oxygen-carrying capacity. Women have lower hemoglobin concentration in their blood than men, on average, which means less oxygen gets picked up in the lungs and delivered to working muscle per liter of blood pumped. Heart size matters too: men have larger hearts and higher stroke volume (the amount of blood pumped per heartbeat) even after accounting for body size, so at maximal effort they’re moving more oxygenated blood per beat. Total blood volume tends to be higher in men as well, which compounds the hemoglobin difference. None of this is about willpower. It’s structural, the same way height differences are structural, and it means comparing your raw number to a partner or training buddy of the opposite sex will usually mislead you more than it informs you.

Where it gets more interesting is menopause, which gets blamed for a lot of fitness decline that the research doesn’t fully back up. A 2025 study out of Durham University measured aerobic capacity and cardiopulmonary function across premenopausal, perimenopausal, and postmenopausal women who maintained similar activity levels, and found no significant differences in VO2 max between the groups, despite very different hormone profiles (Rattley et al., 2025). The postmenopausal group had lost some muscle mass compared to the others, but their aerobic capacity itself held up. The takeaway isn’t that hormones do nothing. It’s that the story is more nuanced than “menopause tanks your fitness”: activity level and muscle mass appear to matter more than estrogen alone, which is genuinely useful to know if you’re perimenopausal and bracing for a number that might not actually fall the way you’ve been told it will.

Why VO2 max drops with age, and what changes that curve

The 10%-per-decade figure comes from the same FRIEND dataset, and it holds up as a rough average across the population (Kaminsky et al., 2015). But it isn’t a straight line. A long-running study out of the Baltimore Longitudinal Study of Aging, which retested the same healthy adults repeatedly over years rather than just comparing different age groups once, found that the decline actually accelerates as you get older: it’s gentler through your 30s and 40s and steepens from your 60s onward, driven by a combination of a lower maximum heart rate, reduced stroke volume, and gradual loss of muscle mass (Fleg et al., 2005).

Training changes that curve substantially. A classic study followed masters endurance athletes who kept training seriously into their 60s alongside sedentary men of the same age, retesting both groups roughly eight years later. The sedentary group’s VO2 max fell by about 12% per decade, in line with the population average. The athletes who kept training lost their fitness at roughly half that rate, about 5–6% per decade (Rogers et al., 1990). Over 20 years, that gap compounds into losing a quarter of your aerobic capacity versus losing half of it, and the variable that separated the two groups wasn’t genetics, it was whether they kept training.

What to actually do with this

I’m not chasing my old number back right now, and I don’t think that’s the point of any of this anyway. A few things I’ve actually changed, and a few I’d suggest regardless of where you’re starting from:

Test it, don’t obsess over it. Retest every few months, not every week. VO2 max moves slowly enough that daily or weekly checks mostly just add noise and pressure, especially on a wearable estimate that already has some built-in error.

Running, cycling, skiing, rowing, swimming, they all work; the differences between them are secondary. Any continuous, rhythmic activity that uses large muscle groups builds cardiorespiratory fitness, and the official exercise-prescription guidelines don’t rank one above another (Garber et al., 2011). That said, modes that recruit more total muscle mass tend to produce somewhat higher VO2 max numbers: treadmill running elicits values roughly 6–10% higher than cycling in the same person, because more muscle is demanding oxygen at once (Basset & Boulay, 2000). Cross-country skiing goes a step further by using the upper and lower body together, which is part of why elite skiers post some of the highest VO2 max values ever recorded in any sport, into the high 80s and low 90s ml/kg/min (Ingjer, 1991). None of this means you should switch sports. Training is also specific: a dedicated cyclist’s biggest gains will show up on a bike, not on a treadmill. Pick whichever of jogging, cycling, skiing, swimming, or rowing you’ll actually do consistently and hard. Any of them raises the number if the intensity is real.

Prioritize intensity over volume if your time is limited. The clearest way to move VO2 max is short, hard efforts near your maximum, three to five minutes at a pace you can only sustain for a few minutes, with recovery between. A meta-analysis of controlled trials found interval training produced roughly two and a half times the VO2 max improvement of steady, moderate-pace cardio over the same training period (Milanović et al., 2015). If you’ve got 30 minutes twice a week instead of the 10 hours you used to have, that’s where to spend it.

If you lift and don’t do separate cardio, know that strength training alone moves the number only a little. Resistance training does raise VO2 max in people who weren’t training before, largely as a side effect of getting fitter overall, but the improvement is modest next to what aerobic or interval work produces on its own (Smart et al., 2022). Heavy squats and a strong deadlift aren’t wasted effort for your cardiovascular system, but they’re not a substitute for it either. If VO2 max specifically is what you’re after, one or two short interval sessions a week will move it further than adding more sets.

If Pilates is your main practice, it’s genuinely doing something, just not as much as dedicated cardio. A meta-analysis found Pilates measurably increases VO2 max compared with no exercise at all (Fernández-Rodríguez et al., 2019). It’s a legitimate part of a fitness routine. But if raising your VO2 max specifically is the goal, pairing it with even one short, harder session a week will get you there faster than more Pilates volume alone.

Compare yourself to your own history, not someone else’s peak. Your number next to your own past self, at your current age and stage of life, tells you far more than stacking it against a training partner, a younger version of you, or a spouse of the opposite sex.

Don’t read a temporary dip as a permanent one. Life stages change training capacity: new parenthood, injury recovery, illness, high-stress work periods. The physiology behind VO2 max responds to training load, and training load is genuinely allowed to go down for a season without that meaning something is broken.

FAQ

Is my Garmin or Apple Watch VO2 max estimate accurate enough to trust? It’s a reasonable trend indicator but not a substitute for a lab test. Wearable algorithms estimate VO2 max from pace and heart rate data and can be off by several ml/kg/min, especially outside of steady-state running. Watch the direction it moves over months rather than fixating on any single reading.

Can I actually improve my VO2 max in my 50s or 60s? Yes. The training response to structured aerobic work doesn’t disappear with age; it’s just working against a bigger downward pull from natural decline. Interval training in particular produces measurable gains at any age, and starting from a lower baseline often means faster relative improvement.

What VO2 max counts as genuinely low or a health concern? Sitting below the 25th percentile for your age and sex, especially the 5th–10th percentile, is the range associated with elevated cardiovascular risk in the research (Ross et al., 2016). That’s a reasonable prompt to talk to a doctor about a supervised fitness plan, not a diagnosis on its own.

Why do elite endurance athletes have scores double the average person’s? Elite marathoners and cross-country skiers can post VO2 max values above 80 ml/kg/min for men and above 70 for women, roughly double the general-population median. That combination of genetics (particularly a large stroke volume and high capillary density) plus a decade or more of specific training is genuinely rare, which is exactly why it shows up at the extreme tail of the distribution rather than the middle.

Is it normal for VO2 max to drop after having a baby or taking time off training? Yes, and it’s not a sign anything is wrong. Training load drops, sleep changes, and recovery capacity shifts, all of which affect the number directly. It typically responds again once consistent training resumes, the same way it would after any extended break.

Should I compare my VO2 max to my partner’s if we train together? Not directly, if you’re different sexes or different ages. The physiological baseline is different enough that a like-for-like comparison mostly just distorts the picture. Compare your trend to your own past scores instead.

Sources

Basset, F. A., & Boulay, M. R. (2000). Specificity of treadmill and cycle ergometer tests in triathletes, runners and cyclists. European Journal of Applied Physiology, 81(3), 214–221. https://doi.org/10.1007/s004210050033

Fernández-Rodríguez, R., Álvarez-Bueno, C., Ferri-Morales, A., Torres-Costoso, A. I., Cavero-Redondo, I., & Martínez-Vizcaíno, V. (2019). Pilates method improves cardiorespiratory fitness: A systematic review and meta-analysis. Journal of Clinical Medicine, 8(11), 1761. https://doi.org/10.3390/jcm8111761

Fleg, J. L., Morrell, C. H., Bos, A. G., Brant, L. J., Talbot, L. A., Wright, J. G., & Lakatta, E. G. (2005). Accelerated longitudinal decline of aerobic capacity in healthy older adults. Circulation, 112(5), 674–682. https://doi.org/10.1161/CIRCULATIONAHA.105.545459

Garber, C. E., Blissmer, B., Deschenes, M. R., Franklin, B. A., Lamonte, M. J., Lee, I. M., Nieman, D. C., & Swain, D. P. (2011). American College of Sports Medicine position stand: Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise. Medicine & Science in Sports & Exercise, 43(7), 1334–1359. https://doi.org/10.1249/MSS.0b013e318213fefb

Ingjer, F. (1991). Maximal oxygen uptake as a predictor of performance ability in women and men elite cross-country skiers. Scandinavian Journal of Medicine & Science in Sports, 1(1), 25–30. https://doi.org/10.1111/j.1600-0838.1991.tb00267.x

Kaminsky, L. A., Arena, R., & Myers, J. (2015). Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: Data from the Fitness Registry and the Importance of Exercise National Database. Mayo Clinic Proceedings, 90(11), 1515–1523. https://doi.org/10.1016/j.mayocp.2015.07.026

Mandsager, K., Harb, S., Cremer, P., Phelan, D., Nissen, S. E., & Jaber, W. (2018). Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Network Open, 1(6), e183605. https://doi.org/10.1001/jamanetworkopen.2018.3605

Milanović, Z., Sporiš, G., & Weston, M. (2015). 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, 45(10), 1469–1481. https://doi.org/10.1007/s40279-015-0365-0

Rattley, C. A., Ansdell, P., Armstrong, M., Felton, M., Dewhurst, S., Yendole, K., & Neal, R. A. (2025). Aerobic capacity and cardiopulmonary variables are not different between premenopausal, late premenopausal, perimenopausal, and postmenopausal women. Physiological Reports, 13(16), e70503. https://doi.org/10.14814/phy2.70503

Rogers, M. A., Hagberg, J. M., Martin, W. H., Ehsani, A. A., & Holloszy, J. O. (1990). Decline in VO2max with aging in master athletes and sedentary men. Journal of Applied Physiology, 68(5), 2195–2199. https://doi.org/10.1152/jappl.1990.68.5.2195

Ross, R., Blair, S. N., Arena, R., Church, T. S., Després, J.-P., Franklin, B. A., Haskell, W. L., Kaminsky, L. A., Levine, B. D., Lavie, C. J., Myers, J., Niebauer, J., Sallis, R., Sawada, S. S., Sui, X., & Wisløff, U. (2016). 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, 134(24), e653–e699. https://doi.org/10.1161/CIR.0000000000000461

Santisteban, K. J., Lovering, A. T., Halliwill, J. R., & Minson, C. T. (2022). Sex differences in VO2max and the impact on endurance-exercise performance. International Journal of Environmental Research and Public Health, 19(9), 4946. https://doi.org/10.3390/ijerph19094946

Smart, T. F., Doleman, B., Hatt, J., Paul, M., Toft, S., Lund, J. N., & Phillips, B. E. (2022). The role of resistance exercise training for improving cardiorespiratory fitness in healthy older adults: A systematic review and meta-analysis. Age and Ageing, 51(6), afac143. https://doi.org/10.1093/ageing/afac143

A note from us We’re Martin and Marina, Astrea’s co-founders. We’re both into data and serious about our own training, but neither of us is a doctor or a clinical researcher. The health and physiology claims in this article come from published, peer-reviewed research, not our own expertise, which is why every article ends with a Sources list above. If a claim doesn’t trace back to a real source, we cut it before it gets published.