Your VO₂max — maximal oxygen uptake, the largest amount of oxygen your body can use during all-out exercise — is the single best measure of aerobic fitness, and one of the strongest predictors of how long you will live. So when people ask what a good score looks like, the honest answer is that it depends on your age and your sex. A figure that is excellent for a 65-year-old would be unremarkable for a 25-year-old. This article sets out what counts as a good VO₂max by age, where the reference numbers come from, and what your score really tells you about your long-term health.
Why does VO₂max fall with age?
VO₂max peaks in your twenties and declines steadily after that. In the largest US reference dataset — the Fitness Registry and the Importance of Exercise National Database (FRIEND) — the average rate of decline was roughly 10% per decade on a treadmill (Kaminsky et al., 2015). The updated analysis of 22,379 tests put the figure a little higher: about 13.5% per decade for treadmill testing and 16.4% per decade for cycle testing (Kaminsky et al., 2021).
That decline is not fixed, though. Much of it reflects falling activity levels and muscle loss rather than the passage of time alone, which is precisely why your number is something you can act on.
What is a good VO₂max by age?
The cleanest way to read your score is against the percentiles for your decade and sex. The 50th percentile is the median — a typical value — so a genuinely good score sits comfortably above it. In the FRIEND treadmill data, the median VO₂max fell from 48.0 ml/kg/min for men aged 20–29 and 37.6 for women, down to 24.4 and 18.3 respectively by ages 70–79 (Kaminsky et al., 2015).
One nuance matters for anyone training on a bike: how you are tested changes the number. VO₂max measured on a cycle ergometer reads lower than on a treadmill, because cycling recruits less muscle mass. In the FRIEND cycling dataset, the median was 41.9 ml/kg/min for men aged 20–29 and 31.0 for women, falling to 19.5 and 14.8 by ages 70–79 (Kaminsky et al., 2016). So compare like with like:
- Find your decade and sex, then check whether your figure sits above or below the median for that group.
- Above the 50th percentile is good; the higher you climb, the better.
- Match the test mode. A cycle-based reading of 35 ml/kg/min is not the same as a treadmill reading of 35.
As a rough guide, scores around the 50th to 60th percentile are usually described as average for your group, the 60th to 80th as good, and anything above the 80th percentile as excellent. The exact cut-offs differ between reference systems, so treat any single label as orientation rather than a verdict. The direction your own number travels over time tells you far more than the band it happens to land in on one test.
Why do men and women have different numbers?
Across every age band, men record higher VO₂max values than women. This is physiological rather than a question of effort: men tend to have larger hearts, greater blood volume and higher haemoglobin mass, all of which raise how much oxygen the body can deliver and use during exercise (Coe and Astorino, 2023). It is why reference charts always separate the sexes — reading your score against the right column is what makes the comparison meaningful.
What your score really says about your longevity
VO₂max is not only a fitness metric; it is one of the most powerful predictors of mortality we have. In a study of 122,007 adults who completed treadmill testing, those in the lowest fitness category carried roughly five times the risk of death of elite performers over the follow-up period — an adjusted hazard ratio of 5.04 (Mandsager et al., 2018). The risk linked to low fitness was comparable to, or greater than, that of smoking, coronary artery disease or diabetes.
Two findings stand out for anyone who worries they have left it too late. There was no upper limit to the benefit — the fittest individuals had the lowest mortality, with no point at which more fitness stopped helping. And the advantage of higher fitness still held in adults aged 70 and over, and in those with high blood pressure (Mandsager et al., 2018). Your VO₂max is a modifiable marker, not a fixed verdict.
Can you move up the chart?
Yes — at any age, and without long hours of exercise. VO₂max is highly trainable. REHIT (reduced-exertion high-intensity interval training) — CAROL’s signature approach, built around two 20-second all-out sprints inside a short session — was developed specifically to improve VO₂max with a minimal time commitment (Metcalfe et al., 2015).
The recent evidence is encouraging. A 2025 randomised controlled trial in 319 previously inactive adults found that a REHIT protocol of two 20-second all-out efforts raised VO₂max by 8–13% over 12 weeks, matching cycle-based sprint interval training (Hu et al., 2025). A gain of that size can effectively set the reference charts back the better part of a decade.
One caveat the evidence is clear about: intensity should be individualised. People starting from lower fitness experience the sprints differently, so the protocol works best when it is matched to the person rather than applied as a blanket prescription (Astorino et al., 2019). Consistency matters more than any single workout: the adaptations accrue when short, hard efforts are repeated across weeks, which is part of why a sustainable, low-time-cost format tends to win out over an ambitious plan you cannot keep up.
The bottom line
A good VO₂max is one that sits comfortably above the median for your age and sex — and the higher it climbs, the longer the evidence suggests you are likely to live, with no clear ceiling on the benefit. Because the bar falls with each passing decade, the more useful question is not “what’s a good score?” but “is mine improving?” VO₂max responds to training at every age, and short, high-intensity sessions are among the most time-efficient ways to raise it. Whatever your number today, it is one of the few health markers genuinely within your control.
