Free tool · Cardio fitness

VO2 max by age and sex

Short answer

In the FRIEND registry of 7,783 lab treadmill tests, median VO2 max was 48.0 mL/kg/min for men and 37.6 for women in their 20s, falling to 32.6 and 23.4 in their 50s. Apple Watch shows its Cardio Fitness estimate in the same units, so you can see roughly where yours falls among people your age.

Last reviewed 12 October 20263 published sourcesNot medical advice

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Where does your VO2 max fall?

Find your Cardio Fitness number in the Health app on iPhone and enter it in mL/kg/min.

Age

years

Sex

FemaleMale

VO2 max

mL/kg/min

Your VO2 max

mL/kg/min

Median, women 40–49

26.7

mL/kg/min

75th percentile

32.4

mL/kg/min

32 mL/kg/min sits about the 73rd percentile (between the 50th and 75th) for women aged 40–49 in the FRIEND registry's measured treadmill tests.

VO2 max chart by age and sex

VO2 max is the most oxygen your body can use during hard exercise, in millilitres per kilogram of body weight per minute. These percentiles come from the FRIEND registry: 7,783 maximal treadmill tests with measured gas exchange, from adults aged 20–79 without known cardiovascular disease, collected by eight U.S. laboratories (Kaminsky et al., 2015 (FRIEND)).

Women: measured VO2 max percentiles (mL/kg/min)
Age	5th	10th	25th	50th	75th	90th	95th
20–29	21.7	23.9	30.5	37.6	44.7	51.3	56.0
30–39	19.0	20.9	25.3	30.2	36.1	41.4	45.8
40–49	17.0	18.8	22.1	26.7	32.4	38.4	41.7
50–59	16.0	17.3	19.9	23.4	27.6	32.0	35.9
60–69	13.4	14.6	17.2	20.0	23.8	27.0	29.4
70–79	13.1	13.6	15.6	18.3	20.8	23.1	24.1

Men: measured VO2 max percentiles (mL/kg/min)
Age	5th	10th	25th	50th	75th	90th	95th
20–29	29.0	32.1	40.1	48.0	55.2	61.8	66.3
30–39	27.2	30.2	35.9	42.4	49.2	56.5	59.8
40–49	24.2	26.8	31.9	37.8	45.0	52.1	55.6
50–59	20.9	22.8	27.1	32.6	39.7	45.6	50.7
60–69	17.4	19.8	23.7	28.2	34.5	40.3	43.0
70–79	16.3	17.1	20.4	24.4	30.4	36.6	39.7

Source: Kaminsky, Arena & Myers, Mayo Clinic Proceedings 2015, Table 3 (FRIEND registry treadmill tests).

How Apple Watch Cardio Fitness compares

Apple Watch shows VO2 max as Cardio Fitness. It estimates the value from your heart rate response during outdoor walks, runs and hikes on fairly flat ground, using a sub-maximal prediction rather than an all-out test (Apple HealthKit: vo2Max). Indoor workouts do not count toward the estimate, the supported range is 14–65 mL/kg/min, and classifications are available from age 20 (Apple Support: cardio fitness).

Because FRIEND measured VO2 max directly at maximal effort and the watch predicts it from everyday exercise, treat the percentile above as a rough placement. The more useful question is whether your own number is drifting up or down over months.

Why VO2 max falls with age

In FRIEND, mean VO2 max for men fell from 47.6 mL/kg/min in their 20s to 25.8 in their 70s, and for women from 37.6 to 18.3, and men were higher than women in every decade (Kaminsky et al., 2015 (FRIEND)). Maximum heart rate also fell with each decade in the same tests, which is one reason the ceiling drops. Age is not the whole story, though: in every decade, the gap between the 25th and 75th percentile is larger than the drop in the median from one decade to the next.

Turn one number into a fitness age

Reps uses your VO2 max and heart data to give you a fitness age and shows what is moving it, from the Apple Watch you already wear.

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Common questions

What is a good VO2 max for my age?

Using the FRIEND registry's measured treadmill data, the 50th percentile is 48.0 mL/kg/min for men and 37.6 for women aged 20–29, 37.8 and 26.7 at 40–49, and 28.2 and 20.0 at 60–69. Anything above your age group's 75th percentile is better than three in four people in that registry.

How does Apple Watch measure VO2 max?

Apple Watch estimates VO2 max from your heart rate response during outdoor walks, runs and hikes on fairly flat ground, using a sub-maximal prediction rather than a maximal lab test. It supports estimates between 14 and 65 mL/kg/min, and its cardio fitness classifications are available from age 20.

Is an Apple Watch VO2 max the same as a lab test?

No. The FRIEND values come from maximal treadmill tests with measured gas exchange. Apple Watch predicts VO2 max from sub-maximal exercise, so treat the comparison as a rough guide and watch your own trend over months.

Sources

Figures on this page were checked against these publications on 12 October 2026.

Kaminsky LA, Arena R, Myers J. Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the Fitness Registry and the Importance of Exercise National Database. Mayo Clinic Proceedings. 2015;90(11):1515–1523. doi.org/10.1016/j.mayocp.2015.07.026
Apple. Track your cardio fitness levels. Apple Support. support.apple.com/en-us/108790
Apple. vo2Max. HealthKit developer documentation. developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/vo2max

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