VO2 Max Chart by Age and Sex (Apple Watch Cardio Fitness Levels)

By Jack Wallner. Updated October 12, 2026.

VO2 max by age and sex: the percentile chart

These are percentiles of lab-measured VO2 max (mL/kg/min) from the Fitness Registry and the Importance of Exercise National Database (FRIEND). The 2015 reference standards are built from 7,783 maximal treadmill tests, with oxygen use measured directly, on adults aged 20 to 79 without known cardiovascular disease. Apple cites this same registry when it describes how Apple Watch judges a low result. Read your row by age, then find where your number lands between the columns. The 50th percentile means half of the tested group scored lower.

Men

Women

Source: Kaminsky, Arena and Myers, Mayo Clinic Proceedings, 2015 (treadmill, directly measured). Ages in years.

Two patterns stand out. First, VO2 max falls with age: the paper reports a decline of roughly 10 percent per decade, from a median of 48.0 (men) and 37.6 (women) in the twenties to 24.4 and 18.3 in the seventies. Second, the sex gap is large at every age, so a number that is high for a 45-year-old woman can be only average for a 45-year-old man. That is why any chart that ignores sex misleads.

How Apple Watch uses age and sex

Apple Watch estimates VO2 max, which Apple calls cardio fitness, from outdoor walk, run and hike workouts. Apple's support page says the supported range is 14 to 65 mL/kg/min, that the Health app can compare your level with others of your age and sex, and that classifications are available from age 20. The Health app shows its own level labels, but the support page does not list numeric cutoffs for them.

Apple does publish how it decides when a result is low. In its cardio fitness white paper, the low-fitness notification threshold for ages 20 to 59 is the lowest quintile (the bottom 20 percent) for your sex and decade of age in FRIEND. On the chart above, that sits between the 10th and 25th percentile columns. For ages 60 and over, Apple uses fixed values instead: 18 mL/kg/min for men and 15 for women.

Two worked examples

• A 42-year-old woman with a reading of 31. Her row is 40-49 in the women's table. 31 is above the median of 26.7 and just under the 75th percentile of 32.4, so she is above average for her group.
• A 55-year-old man with a reading of 30. His row is 50-59 in the men's table. 30 is between the 25th percentile (27.1) and the median (32.6), so he is a little below the middle of his group.

Why your watch may not match the chart

The chart comes from lab treadmill tests taken to exhaustion. Your watch makes an estimate from heart rate, pace and motion on easier outdoor workouts. Apple's validation reports a mean error of 1.4 mL/kg/min with a standard deviation of 4.7, so an individual reading can sit several points away from a lab result. Apple lists specific causes of a wrong estimate:

• An incorrect age, sex or weight in the Health app, which skews every estimate.
• Heart-rate-limiting medications, such as beta blockers, that are not entered in Health Details. Apple says these users get higher-than-actual estimates.
• Carrying a heavy pack or child, pushing a stroller, or running on sand, which raise the work done without the watch seeing it.
• Heat, dehydration, caffeine or a recent move to high altitude, which raise heart rate and can push the estimate down.

Because of that spread, the trend over weeks matters more than any single reading. A reading that moves from one percentile band to the next is more informative than a one-point change.

How VO2 Max helps

VO2 Max & Cardio Fitness reads the cardio fitness estimate already stored in Apple Health, read-only, and shows it as a value with its date, a trend, widgets and an Apple Watch app. In VO2+ you can enter your age and a male or female reference, and the app compares your latest estimate with its own simplified age and sex curve. That curve runs from 41 (female) and 49 (male) at age 20 down to 24 and 30 at age 70, and the app labels you below, around, above or well above a typical range around it. It is a broad guide for setting a personal target, and it is not Apple's classification or the FRIEND percentiles above. Fitness age works the same way and is labeled an estimate in the app.

Frequently asked questions

What is a good VO2 max for my age?

Compare your number with the median for your age and sex in the chart above. For example, the FRIEND median for men aged 40 to 49 is 37.8 mL/kg/min and for women aged 40 to 49 it is 26.7. A reading above the median is better than half of the tested group, and a reading near the 75th percentile is above average.

What VO2 max does Apple Watch consider low?

For ages 20 to 59, Apple's white paper sets the low threshold at the lowest quintile for your sex and age by decade in the FRIEND registry. For ages 60 and over it uses 18 mL/kg/min for men and 15 for women.

Is Apple Watch VO2 max accurate?

Apple reports a mean error of 1.4 mL/kg/min with a standard deviation of 4.7 against a reference in its validation group, so single readings can be off by several points. Wrong profile data, heart-rate medications you have not entered, and non-standard loads such as a heavy pack can make it worse.

Why is my Apple Watch VO2 max lower than the chart says it should be?

Lab charts use maximal treadmill tests, while the watch estimates from outdoor walks, runs and hikes. Check that your age, sex and weight are correct in Health, and note that heat, caffeine, dehydration and altitude can push an estimate down.

Does this chart apply to under-20s or over-79s?

No. The FRIEND treadmill standards cover ages 20 to 79, and Apple provides classifications from age 20, so the chart should not be applied outside that range.

Sources

1. Apple Support: Track your cardio fitness levels
2. Apple: Using Apple Watch to Estimate Cardio Fitness with VO2 max (white paper, May 2021)
3. Kaminsky, Arena, Myers. Reference Standards for Cardiorespiratory Fitness Measured With Cardiopulmonary Exercise Testing: Data From FRIEND. Mayo Clinic Proceedings, 2015

This page is general fitness information, not medical advice. VO2 max estimates and fitness age are approximations, and the app does not diagnose, treat, cure or prevent any condition. Talk to a clinician about your health.