VO2 max is the clearest single number for aerobic fitness. It measures how much oxygen your body can use during hard exercise, and it tells you more about cardiovascular health than resting heart rate or body weight ever could. But a VO2 max score only means something in context — a 45 ml/kg/min result is average for one age group and elite for another.
This guide breaks down average VO2 max by age and sex, explains what counts as good, and covers why cardio capacity changes over a lifetime and what you can do about it.
What Is VO2 Max, Quickly
VO2 max is the maximum rate at which your body can take in, transport, and use oxygen during intense effort. It’s expressed in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). The higher the number, the more oxygen your heart, lungs, and muscles can process per minute of hard work — which usually translates to better endurance, faster recovery between efforts, and a lower risk of cardiovascular disease.
If you haven’t tested your own number yet, a VO2 max calculator is a fast way to estimate it from resting heart rate, age, and recent race or run data, without needing a lab.
Average VO2 Max by Age (Men)
These are general population averages, not athlete benchmarks. Trained individuals will sit well above these ranges at every age.
- 20–29: 42–46 ml/kg/min average
- 30–39: 39–43 ml/kg/min average
- 40–49: 36–40 ml/kg/min average
- 50–59: 33–36 ml/kg/min average
- 60+: 28–33 ml/kg/min average
Average VO2 Max by Age (Women)
Women’s VO2 max averages typically run lower than men’s at every age bracket, largely due to differences in hemoglobin concentration, heart size, and body composition — not fitness level.
- 20–29: 35–40 ml/kg/min average
- 30–39: 33–37 ml/kg/min average
- 40–49: 30–34 ml/kg/min average
- 50–59: 27–31 ml/kg/min average
- 60+: 24–28 ml/kg/min average
These ranges shift depending on the testing method and population sample, so treat them as a general reference point rather than a strict cutoff. A calorie deficit for fat loss combined with regular cardio work can meaningfully shift where you land in these ranges over a few months of consistent training.
What Counts as a Good VO2 Max Score
“Good” depends entirely on age and sex, which is why raw VO2 max numbers get misread so often. A 38 ml/kg/min score is unremarkable for a 25-year-old man but excellent for a 55-year-old woman. Most fitness classification charts break scores into five to six tiers — poor, below average, average, above average, good, and elite — with the cutoffs shifting downward for each older age bracket and each sex.
As a simple gut check: if your VO2 max sits within or above the average range for your age and sex bracket above, you’re in a solid position. Moving one full tier up from where you currently sit is a realistic, meaningful training goal rather than chasing an absolute number that ignores your age.
To put the tier system in concrete terms, take a 35-year-old man. A VO2 max below roughly 35 ml/kg/min would fall in the “below average” tier for that bracket, 39–43 sits at average, 44–47 moves into “above average,” and anything above 48 starts crossing into “good” to “excellent” territory for his age group. A 35-year-old woman follows a similar tier structure, just shifted several points lower across every threshold. The exact cutoffs vary slightly between testing protocols and reference populations, but the shape of the curve — five or six tiers, each roughly 4–6 points wide — holds across most classification systems.
What matters more than hitting a specific tier label is the trend over time. Someone who moves from “below average” to “average” over a year of consistent cardio training has made a bigger real-world improvement to their cardiovascular health than someone who was already sitting in “good” and stayed flat. Treat the tiers as a map for where you stand today, not a scoreboard to obsess over month to month.
What an Elite VO2 Max Looks Like
Elite endurance athletes post numbers that dwarf general population averages. Top male distance runners and cross-country skiers have recorded VO2 max scores above 80–90 ml/kg/min, and elite female endurance athletes commonly sit in the high 60s to low 70s. These figures represent genetic ceiling combined with a decade or more of structured aerobic training — they’re not a realistic short-term target for most people, but they illustrate how much headroom exists above “average.”
For context, moving from an average score into the “good” tier for your age bracket is a substantial, achievable improvement that meaningfully lowers cardiovascular risk — you don’t need elite-athlete numbers to get the majority of VO2 max’s health benefit.
Why VO2 Max Declines With Age
VO2 max naturally trends downward starting around age 25–30, and the decline tends to accelerate after 50 if training volume and intensity aren’t maintained. A few physiological factors drive this:
- Lower maximum heart rate: max heart rate drops roughly one beat per year on average, which caps how much blood the heart can pump during peak effort.
- Reduced stroke volume: the heart’s chambers and vessel elasticity change slightly with age, which can reduce how much blood is pumped per beat.
- Muscle mass and mitochondrial density loss: less muscle tissue and fewer mitochondria per cell mean less oxygen-processing capacity at the tissue level, tying VO2 max decline directly to natural muscle loss over time.
- Lower training volume: this is the biggest modifiable factor — most of the “aging” decline in population data reflects people training less as they get older, not pure biology.
Population studies typically show VO2 max declining somewhere between 5–15% per decade after age 30 in people who don’t train specifically for aerobic fitness, with the rate of decline picking up more noticeably after age 50. But that range is wide for a reason — it reflects the enormous gap between someone who stops structured exercise almost entirely and someone who keeps some form of cardio in their routine but scales back intensity. The 5% end of that range belongs to people who stay active; the 15% end belongs to people who go fully sedentary.
How Much of the Decline Is Actually Preventable
Research comparing lifelong endurance athletes to sedentary adults shows the biological decline in VO2 max is real, but it’s substantially slower in people who keep training consistently through their 40s, 50s, and 60s. Sedentary adults can lose VO2 max at close to double the rate of those who maintain regular aerobic training. In practical terms: a well-trained 50-year-old can post a VO2 max that beats an untrained person half their age.
This is the core reason cardio capacity is worth tracking and training deliberately rather than treating as a fixed number tied to your birth year.
How to Improve Your VO2 Max at Any Age
VO2 max responds well to training, and improvement is possible at essentially any age with a consistent, structured approach.
- High-intensity interval training (HIIT): short bursts near or above your current max effort, repeated with recovery periods, are consistently shown to produce the fastest VO2 max gains.
- Zone 2 aerobic base work: longer, easier-paced sessions build the aerobic base and capillary density that support higher-intensity work.
- Progressive overload for cardio: gradually increasing pace, duration, or interval intensity over weeks — the same progressive overload principle that drives strength gains applies directly to cardiovascular training.
- Strength training: building and maintaining muscle mass supports the tissue-level oxygen use that underlies VO2 max, especially as natural muscle loss accelerates with age.
- Consistency over intensity: a sustainable 3–4 sessions per week over months outperforms sporadic all-out efforts for long-term VO2 max improvement.
A practical starting structure for most people is one to two HIIT sessions per week — something like four to six rounds of three to four minutes near maximal effort with equal-length recovery — paired with two to three longer, easier Zone 2 sessions where you can hold a conversation but feel like you’re working. This combination trains both ends of the aerobic system: the intervals push your ceiling, and the base work builds the capillary and mitochondrial infrastructure that supports it.
Most studies show measurable VO2 max improvement within 6–12 weeks of consistent structured training, with continued gains over 6 months or longer for people starting from a lower baseline. People who are more sedentary at the start tend to see the fastest early gains, simply because there’s more room to improve — someone already training at a high level will see smaller, slower increases even with a well-designed program, since they’re closer to their individual ceiling.
How VO2 Max Connects to Overall Fitness Tracking
VO2 max is one piece of a bigger fitness picture. Pairing it with strength benchmarks like a one rep max calculator and body composition metrics like an FFMI calculator gives a fuller view of where you stand — cardiovascular capacity, strength, and body composition each tell a different part of the story, and tracking all three gives a much more complete read on fitness than any single number alone.
The Bottom Line
VO2 max declines with age, but the rate of that decline is largely under your control. Average scores drop steadily by decade, but consistent aerobic training — combined with strength work and a sustainable training split — can keep your number well above the population average for your age group, often by a wide margin. Track your score over time rather than comparing it to a single universal target, and treat gradual, consistent improvement as the real win.