The guide

What's a good VO2 max for your age and sex?

By GyroscopeUpdated November 15, 20267 sources

Good means above the middle for your age and sex, and great means the top quarter. On the US chart from 16,278 treadmill tests, the middle is 35 for men in their 40s and 26 for women, and the top quarter starts near 43 and 32.

Why does every chart give a different answer?

Look up the same number in three places and you can get three verdicts. Your watch gives you a cardio fitness level, a chart on a gym wall gives you another, and a calculator online gives you a third. Each one is comparing you with a different group of people.

Charts come from whoever happened to be tested. When the US FRIEND registry rebuilt its reference chart in 2022 from 22,379 lab tests, the treadmill numbers came out 1.5 to 4.6 points lower than its own 2015 tables. It was the same registry, with more people tested. An older chart can put you a whole group lower than the current one would.

The kind of test changes it too. People score lower on a bike than on a treadmill. Men in their 40s had a middle of 27.4 on a bike and 35.3 on a treadmill, so a bike result judged on a treadmill chart looks worse than it is.

Then there’s the number itself. Watches estimate it, and in a 2026 lab check Apple Watch Series 10 put only 5 of 35 people in their right FRIEND band. If your number came from a watch, your rank comes with a margin. How to measure it has how far to trust each source.

A simple way to picture it

Think of the age groups at a big marathon. A finishing time that puts you in the middle of the pack at 25 can win your age group at 70. Nobody thinks the 70-year-old cheated. The time means something different at each age.

VO2 max works the same way, except the age groups slide underneath you every year. Your number can stay put while your place in the field changes.

The US chart

These come from the FRIEND 2022 treadmill tables: 9,564 men and 6,714 women, apparently healthy adults aged 20 to 89, tested in 34 US labs between 1968 and March 2021. All in ml/kg/min.

Men

Women

The middle, the 10th and the 90th percentiles are published. The 25th and 75th are worked out by drawing straight lines between the published deciles, so treat them as close, not exact.

What do the groups mean?

We use the plain group names from the biggest study of fitness and survival, 122,007 people who took a treadmill test at the Cleveland Clinic (Mandsager 2018), placed on the FRIEND chart:

• Low: the bottom quarter for your age and sex.
• Below average: the 25th to 49th percentile.
• Above average: the 50th to 74th.
• High: the 75th and up. Over the 90th we add “top 10 percent”.

That study also had an “elite” group, the top 2.3 percent. The FRIEND table stops at the 90th percentile, so we don’t claim anyone is elite from it.

The groups aren’t just labels. In the Cleveland Clinic patients, below average against above average carried 1.41 times the risk of death, the same as smoking. Why it predicts how long you live has the rest.

How much does your age change the verdict?

A lot. Here’s one number, 42, across the decades.

Look at the man’s column. He doesn’t need to get any fitter to climb from below average to the top 10 percent. He needs to not get worse while everyone his age does. In healthy adults followed for about eight years, VO2 max fell 3 to 6 percent a decade in the 20s and 30s and more than 20 percent a decade in the 70s, whatever their activity (Fleg 2005). Holding flat beats that slope. VO2 max and age shows how people do it.

What’s my fitness age?

Fitness age is the age at which your number would be exactly the US middle for your sex. We draw it through the middle values at 25, 35, 45 and so on up to 85.

• A man at 42 has the engine of a typical 32-year-old.
• A man at 38 has the engine of a typical 39-year-old.
• A woman at 30 has the engine of a typical 33-year-old.
• A woman at 35 has the engine of a typical 27-year-old.

Above the middle for people in their 20s, we say “25 or younger”. Below the middle for people in their 80s, “85 or older”. Our fitness age comes from measured lab tests, not from a questionnaire, and a bike number is judged on the bike middles.

Why are women’s numbers lower?

On the US chart, women’s middles sit 21 to 27 percent below men’s in the same decade: 36.6 against 46.5 in the 20s, 25.7 against 35.3 in the 40s. That’s why a woman’s number only means something on the women’s chart. A woman in her 40s at 33 is in the top quarter for women her age, about the 80th percentile, and below the middle for men her age.

The same goes the other way at the top. The men in the trial that made the 4x4 famous started at 55 to 60, around the 80th to 90th percentile for men in their 20s, and the study called them “moderately trained”.

Bike or treadmill?

If your lab test was on a bike, use a bike chart. The FRIEND bike middles are lower in nearly every decade:

Watches and running tests are judged on the treadmill chart. The bike groups were smaller (2,439 men and 3,662 women), with only 52 men and 27 women in their 80s, so the oldest bike rows are the least certain.

How good is good enough?

For health, the steepest part of the curve is at the bottom. Across 33 studies, people with low fitness had 1.40 times the risk of death of people with middling fitness and 1.70 times the risk of the fittest, so most of the gap sat in that first step (Kodama 2009). At the Cleveland Clinic, below average against above average carried the same extra risk as smoking. Above that the benefit kept growing, with no ceiling found, but each step bought less.

Late in life there’s a floor too. Below about 18 for men and 15 for women, loss of independence seems likely (Shephard 2009), and the US middle for people in their 80s is 17.6 for men and 15.4 for women. Building a high number in midlife gives you more room above that line when you get there.

Find yours

Your number, age and sex in, your percentile, group and fitness age out, plus how far the next group up is and how long that took people in a trial.