What Is VO₂ Max, and Why Is It Linked to Living Longer?

VO₂ max, or maximal oxygen uptake, is the most oxygen your body can use during all-out exercise, in millilitres per kilogram of body weight per minute (mL/kg/min). It sums up how well your heart, lungs, blood, and muscles work together, which is why it’s the standard measure of cardiorespiratory fitness. It’s also one of the strongest predictors of how long people live.

This article is general information, not medical advice.

How It’s Measured

VO₂ max is measured in a cardiopulmonary exercise test: you run on a treadmill or ride a bike with the effort rising every minute or two, wearing a mask that measures the oxygen you breathe in and the carbon dioxide you breathe out, until you can’t go on. Watches estimate it instead from your heart rate and pace during runs and walks, which is quicker but less exact; see How Accurate Is Your Watch’s VO₂ Max Estimate?

Typical Values

The Fitness Registry and the Importance of Exercise National Database (FRIEND) collected treadmill tests from healthy US adults. Kaminsky and colleagues published its reference values in 2015; the medians were:

Age	Men, median	Women, median
20 to 29	48.0	37.6
30 to 39	42.4	30.2
40 to 49	37.8	26.7
50 to 59	32.6	23.4
60 to 69	28.2	20.0
70 to 79	24.4	18.3

Values are in mL/kg/min. Each decade’s median is lower than the one before, and the spread within an age group is wide: in FRIEND, men in their 40s ranged from under 27 at the 10th percentile to over 52 at the 90th.

Why It Predicts a Longer Life

• Each step counts. In a meta-analysis of 33 studies, Kodama and colleagues found that each 1 metabolic equivalent (MET, 3.5 mL/kg/min) higher fitness was linked to a 13% lower risk of death from any cause and a 15% lower risk of heart disease.
• The least fit have the most to gain. In 122,007 patients who had treadmill tests at the Cleveland Clinic, Mandsager and colleagues found that those with low fitness had about five times the risk of death of the fittest, a gap comparable to or bigger than that of smoking or diabetes. The biggest difference was between the lowest group and the next.
• It’s a vital sign. A 2016 American Heart Association scientific statement, led by Ross, argued that fitness should be assessed routinely in clinical practice, like blood pressure.

These studies are observational: fitter people differ in other ways too. But trials show that training raises VO₂ max, and the link holds after accounting for many other risk factors.

How to Raise It

• Regular aerobic exercise. Most of the gain comes from doing more, such as reaching the 150 to 300 minutes of moderate activity a week in the World Health Organization’s guidelines.
• Some hard intervals. In a trial of 40 moderately trained men by Helgerud and colleagues, four 4-minute intervals at 90% to 95% of maximum heart rate, three times a week for 8 weeks, raised VO₂ max more than the same work done at a steady, easier pace.
• Losing excess weight raises VO₂ max per kilogram even without any change in your heart and lungs.

Following It in Kaizora

Kaizora keeps VO₂ Max, from a maximal exercise test, apart from a watch’s Estimated VO₂ Max, since they’re different measurements. Apple Health’s export brings in your Apple Watch’s estimate, and you can log a lab test’s result by hand. Both appear on Fitness and Vitals, and the Kaizora Longevity Score uses your VO₂ max’s percentile for your sex and age among FRIEND’s tests as its cardiorespiratory fitness component.

The Short Version

• VO₂ max is the most oxygen your body can use, in mL/kg/min.
• It falls with age; FRIEND’s median for men in their 40s is about 38 and for women about 27.
• Higher fitness is linked to a much lower risk of death, most at the low end.
• Regular aerobic exercise and some intervals raise it.

Sources

• Kaminsky LA et al., “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 90, no. 11 (2015): 1515–1523. doi:10.1016/j.mayocp.2015.07.026
• Kodama S et al., “Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis,” JAMA 301, no. 19 (2009): 2024. doi:10.1001/jama.2009.681
• Helgerud J et al., “Aerobic high-intensity intervals improve VO₂max more than moderate training,” Medicine & Science in Sports & Exercise 39, no. 4 (2007): 665–671. doi:10.1249/mss.0b013e3180304570
• Mandsager K et al., “Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing,” JAMA Network Open 1, no. 6 (2018): e183605. doi:10.1001/jamanetworkopen.2018.3605
• Ross R et al., “Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign: a scientific statement from the American Heart Association,” Circulation 134, no. 24 (2016). doi:10.1161/CIR.0000000000000461