What Is the Average VO2 Max by Age for Men and Women?

VO2 max, the maximum rate at which your body can use oxygen during intense exercise, peaks in the twenties and declines steadily from there. In a large study of healthy adults, men aged 20 to 29 averaged about 54 mL/kg/min while women in that group averaged about 43 mL/kg/min, with both sexes losing roughly 8 percent per decade after that peak.¹ Those numbers, though, sit at the center of a wide range shaped by fitness level, body composition, sex, and how the measurement is done.

Typical Values From Childhood Through Old Age

A large review of directly measured VO2 max in untrained, healthy people across the United States, Canada, and several European countries laid out norms spanning ages 6 to 75. In boys, relative VO2 max starts around 47.5 mL/kg/min at age six, rises to about 50 by age 12 and roughly 48 by age 18, then gradually falls to about 35 by age 50 and 25 by age 75. Girls follow a similar arc at lower absolute levels: about 42.5 at age six, peaking near 44 around age 12, dropping to around 41 by 18, about 28 by 50, and roughly 17.5 by age 75.² A Norwegian study of nearly 4,000 adults confirmed the general pattern, finding that among 20- to 29-year-olds, men averaged about 54 and women about 43 mL/kg/min, with each decade bringing a loss of roughly 3.5 mL/kg/min for both sexes.³

A few things stand out in these data. First, the relative values (adjusted for body weight) in children are surprisingly high compared with young adults. That partly reflects the mathematical effect of smaller body mass in the denominator. Second, the decline after the twenties is not perfectly linear. Most studies find modest losses through the thirties and forties, then steeper drops after 50 or 60. Third, these are population averages for untrained people. Trained individuals at any age can sit well above their age-matched norm, and very sedentary people can fall well below it.

Why VO2 Max Falls With Age

The decline is driven by changes on both sides of the oxygen-delivery equation. On the cardiovascular side, maximum heart rate drops predictably with age, and the heart’s ability to pump blood during all-out effort shrinks along with it. On the muscle side, lean mass declines, capillary density falls, and the mitochondria inside muscle cells become less efficient at turning oxygen into energy.⁴ In very old adults, the peripheral muscle changes become especially severe. Research suggests that skeletal muscle oxygen consumption can drop by roughly half even when oxygen delivery from the bloodstream is held constant, pointing to mitochondrial dysfunction as a major bottleneck in advanced age.⁵

Body composition also plays a quiet but important role. Gaining fat mass while losing muscle increases the denominator of the mL/kg/min equation (your weight goes up) while decreasing the numerator (less metabolically active tissue is doing the work). A study of postmenopausal women found that central abdominal fat accumulation was a strong independent predictor of lower VO2 max, regardless of age or menopausal timing.⁶ So part of what looks like an age-related decline is really a body-composition change that happens to track closely with age.

The Gap Between Men and Women

At every age, men average higher VO2 max values than women. A Dutch/Flemish registry covering ages 6 to 65 found the overall difference was about 18 percent.⁷ This gap reflects differences in hemoglobin concentration (men carry more oxygen per liter of blood), heart size relative to body mass, and the proportion of lean tissue versus fat. Men tend to have about 10 to 15 percent more hemoglobin and, on average, a larger stroke volume for their body size.

In women, menopause adds another variable. Research has found that time since menopause correlates with VO2 max decline, though age remains the stronger predictor.⁸ The hormonal shifts of menopause accelerate fat redistribution toward the midsection and can reduce lean mass, both of which nudge VO2 max downward beyond what pure chronological aging would predict.

How VO2 Max Develops in Children and Adolescents

In children, the trajectory looks different from adults. Absolute VO2 max (in liters per minute) rises steadily as kids grow, driven largely by increases in body size, heart size, and lung capacity. A classic study of Scandinavian children found that absolute VO2 max climbed during the prepubertal years mainly as an effect of normal growth, then leveled off toward the end of adolescence, reaching averages of about 3.2 L/min for boys and 2.5 L/min for girls.⁹

When expressed per kilogram of body weight, though, the picture shifts. Normal-weight boys show a gradual climb from roughly 47 mL/kg/min at age 8 to about 54 by age 17. Normal-weight girls peak earlier, around 43 at age 11, dip to about 41.5 by 15, and bounce back slightly at 16.¹⁰ The dip in girls likely reflects the increase in body fat that accompanies female puberty. Overweight and obese children showed noticeably lower relative VO2 max values at every age, and obese boys showed essentially no improvement between ages 8 and 15, suggesting that excess body mass can blunt what would otherwise be a natural upward trend during growth.

Sedentary Versus Active Decline Rates

One of the most practical findings in the VO2 max literature is how dramatically exercise habits change the rate at which aerobic fitness declines. A longitudinal study of sedentary men found a decline of about 12 percent per decade, while master athletes who maintained vigorous endurance training saw only about a 5.5 percent decline per decade, roughly half the sedentary rate.¹¹

The story is more nuanced for women. A meta-analysis found that sedentary women lost about 3.5 mL/kg/min per decade, active women lost about 4.4, and endurance-trained women lost about 6.2. That seems counterintuitive until you consider that trained women start much higher, so while the absolute drop is bigger, the percentage decline per decade was actually very similar across all three groups, around 10 to 11 percent.¹² The takeaway for both sexes is the same: exercise does not stop the decline, but it ensures you’re declining from a much higher starting point, which keeps you above critical functional thresholds for longer.

What Master Athletes Teach Us

Master athletes, typically defined as competitive athletes over 35 or 40, serve as a kind of natural experiment in how well the body can hold up with sustained training. Peak endurance performance appears to hold roughly steady until the mid-thirties, then decreases modestly through the fifties, with steeper drops after 60.¹³ The falling VO2 max is considered the main physiological driver behind those performance declines.

How much of the drop is inevitable biology versus a gradual reduction in training volume? A study of master endurance athletes found that changes in training volume explained about 54 percent of the observed VO2 max decline in men and about 39 percent in women.¹⁴ Even among athletes who consider themselves “still training hard,” total volume and intensity tend to drift downward with age due to injury, recovery constraints, and competing life demands. Some of the decline attributed to aging is really a decline in training stimulus.

That said, lifelong exercise cannot override every age-related change. Maximum heart rate drops at roughly the same rate regardless of fitness level, and some degree of mitochondrial deterioration seems unavoidable. A narrative review highlighted that even with consistently high exercise loads across a lifetime, VO2 max still declines in a roughly linear fashion, though values remain well above population norms at every age. The review cited a centenarian cyclist with a measured VO2 max of 35 mL/kg/min, a value that would be considered average for an untrained 50-year-old man.¹⁵

The Functional Threshold That Actually Matters

For most people, the practical importance of VO2 max is less about athletic performance and more about staying independent as they age. Research on older adults living independently found that the minimum aerobic capacity needed for basic self-sufficiency (walking, climbing stairs, carrying groceries) was about 18 mL/kg/min for men and 15 mL/kg/min for women at age 85.¹⁶ Falling below those levels means daily tasks become exhausting or impossible without assistance.

This is where the sedentary versus active decline rates become concrete. If an untrained 50-year-old man sits at around 35 mL/kg/min and loses 12 percent per decade, he crosses the independence threshold in his mid-seventies. A fitter 50-year-old starting at 45 might not cross it until his nineties. The math is rough, but the principle holds: a higher VO2 max at midlife buys more years of independent living.

VO2 Max and Mortality Risk

A large study that followed over 120,000 patients through exercise treadmill testing found that low cardiorespiratory fitness carried a mortality risk comparable to or greater than smoking, diabetes, and coronary artery disease. People with elite fitness had an 80 percent lower risk of death compared to those in the lowest fitness group. Even the jump from below-average to above-average fitness was associated with a meaningful reduction in mortality risk.¹⁷ The researchers found no upper ceiling where more fitness stopped being beneficial, which surprised some cardiologists at the time.

A Swedish study with 46 years of follow-up put a number on it: each 1 mL/kg/min increase in VO2 max at midlife was associated with about 45 extra days of life expectancy. People with fitness above the upper limit of normal lived an average of nearly five years longer than those below the lower limit of normal.¹⁸ This makes VO2 max one of the strongest single predictors of how long you are likely to live, stronger than most blood markers that get far more attention in routine medical check-ups.

Can You Meaningfully Improve VO2 Max After 60?

Yes. A meta-analysis of controlled trials in sedentary older adults found that endurance training produced an average improvement of about 3.8 mL/kg/min, roughly a 16 percent increase. Programs lasting more than 20 weeks at moderate intensity (about 60 to 70 percent of VO2 max) tended to produce the best results.¹⁹ A gain of 3.8 mL/kg/min may not sound like much, but for someone hovering near the independence threshold, it represents a significant buffer.

Interval training appears to have an edge over steady-state cardio in middle-aged and older adults. A meta-analysis comparing the two found that interval training produced VO2 max gains of about 2.3 mL/kg/min, versus about 1.3 for moderate continuous exercise, a statistically meaningful difference.²⁰ A systematic review found that no study reported high-intensity interval training to be less effective than moderate continuous training for improving cardiorespiratory fitness in older adults.²¹ Interval training also showed benefits for resting heart rate and blood pressure beyond what other exercise modes achieved.²²

The caveat with interval training in older populations is the same as in any population: it requires adequate screening and a sensible ramp-up period, especially for people who have been sedentary. But the evidence is fairly clear that age alone is not a barrier to meaningful aerobic improvement.

How Accurate Is the Number on Your Watch?

Many people now encounter their VO2 max estimate through a wrist-worn device rather than a lab. Those estimates deserve some skepticism. A validation study of the Apple Watch Series 7 found that it underestimated measured VO2 max by about 4.5 mL/kg/min on average, and the reliability between the watch estimate and a lab test was poor. The mean absolute percentage error was about 16 percent, and individual readings could be off considerably more.²³ Garmin watches showed the opposite problem in a separate study: they overestimated VO2 max by about 14 mL/kg/min compared to a clinical exercise test, with wide limits of agreement.²⁴

Even standard gym-based submaximal exercise tests, which use formulas to predict VO2 max from heart rate at a given workload, overestimate the true value. A study comparing the common ACSM running equation found that submaximal tests overestimated VO2 max by about 3.4 to 3.8 mL/kg/min, while maximal exercise tests using the same equation overestimated by nearly 10.²⁵ The gold standard remains a cardiopulmonary exercise test in a lab with a metabolic cart measuring exhaled gases. Everything else is an approximation.

What this means practically: if your smartwatch says your VO2 max is 42, the true number could plausibly be anywhere from the mid-thirties to the upper forties. Tracking trends over time on the same device is more informative than treating any single reading as gospel. If you see a steady upward trend across several months, your fitness is improving, even if the absolute number is off.

Population-Level Trends Are Moving in the Wrong Direction

While individual exercisers can push their numbers up, the population-wide story is less encouraging. A study of the Swedish working-age population between 1995 and 2017 found that average relative VO2 max fell by about 10.8 percent, with roughly a third of that decline explained by people simply getting heavier. The proportion of adults classified as having low cardiorespiratory fitness nearly doubled, rising from 27 to 46 percent. Men, younger adults, people with less education, and those in rural areas saw the steepest declines.²⁶

Data from the Cooper Center in the United States tell a slightly more complicated story. Over a 40-year period, estimated VO2 max in men actually rose by about one metabolic equivalent across all age groups, with the biggest gains in the 1970s and 1980s, likely reflecting the jogging and fitness boom. But that trend flattened and began to reverse in the most recent decade, especially in younger men.²⁷ The Cooper Center sample skews toward health-conscious, clinic-attending adults, so the national picture is likely worse than what that cohort suggests.

Nutrition and VO2 Max in Older Adults

Diet is not usually the first thing people think about when trying to raise VO2 max, and the research reflects that: exercise is the dominant lever. Still, some nutritional strategies show modest promise for older adults in particular. Dietary nitrate, most commonly consumed as concentrated beetroot juice, has been studied for its ability to improve oxygen efficiency. In healthy older adults, nitrate supplementation sped up the body’s adjustment to increased oxygen demand during treadmill walking, though it did not reduce the overall oxygen cost of exercise or improve walking speed.²⁸

Combining nitrate with citrulline, an amino acid that also boosts nitric oxide production, showed somewhat broader effects. A supplementation trial in healthy older adults found a small but significant reduction in blood pressure and a 5.2 percent increase in maximal cycling power output, along with lower heart rate and oxygen consumption during submaximal cycling. Peak VO2 max itself was not increased, but the improved efficiency during moderate effort translated into being able to do more work before hitting that ceiling.²⁹ These are small effects compared with what exercise training produces, but they may be useful as an add-on, especially for people whose exercise capacity is limited by cardiovascular constraints like high blood pressure or stiff arteries.

Sarcopenic Obesity and the Double Hit

One clinical scenario that accelerates VO2 max loss beyond what normal aging would predict is sarcopenic obesity, the combination of muscle loss with excessive fat gain. This is not just a matter of being overweight. Sarcopenic obesity involves deterioration in the quality of the remaining muscle, not just its quantity. Research on older adults found that those with low muscle quality had significantly lower VO2 max and worse cardiac filling patterns compared with older adults who had preserved muscle quality, even after accounting for other health conditions.³⁰

This matters because sarcopenic obesity is increasingly common and is easily missed. Someone can maintain a stable body weight for decades while gradually swapping muscle for fat. Their VO2 max drops faster than their age peers, their functional reserve shrinks, and by the time the problem becomes obvious, they may already be close to the independence threshold described earlier. Resistance training is the most direct countermeasure, but it rarely shows up in conversations about VO2 max, which tend to focus exclusively on cardio. Maintaining muscle mass preserves the peripheral oxygen-extraction capacity that becomes a bottleneck in older age.