How to measure your VO2 Max and why it's important

Woman taking VO2 max test
(Image credit: Shutterstock)

VO2 max has long been a measure of aerobic fitness valued by endurance athletes, but it’s not a stat that should just be of interest to keen sportspeople, because a high VO2 max is also linked with general health and longevity.

It’s easier than ever to get an estimate of your VO2 max these days, as many of the best sports watches and smartwatches will provide one based on your workouts and heart rate. What exactly is your VO2 max though, and what is the best way to measure it? You’ll find the answers below, plus more info on why your VO2 max matters.

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What is VO2 max?

VO2 max is a measure of your aerobic capacity, and more specifically the maximum amount of oxygen your body can use while exercising. It’s measured in milliliters of oxygen per kilo of bodyweight, per minute of exercise, and the higher your VO2 max the better, because the more oxygen your body can use the fitter you are, especially for endurance activities.

How do you measure your VO2 max?

The most accurate way to measure your VO2 max is to do a ramp test while wearing a mask that measures the oxygen and carbon dioxide in the air you inhale and exhale. A ramp test usually involves running or cycling at progressively higher effort levels until you max out and have to stop.

You can also do a max effort test without the mask to get an estimate of your VO2 max. The classic beep test, where you run 20-meter shuttles in time with beeps that get closer and closer together is actually a great way to measure your VO2 max using a calculator that uses the level you hit in the test to estimate your VO2 max.

Both of the above methods involve working at a maximal effort, but you can also get an estimate of your VO2 max from sports watches based on your general training. The watches will use info like your heart rate, speed/pace and distance during outdoor activities to estimate your VO2 max.

This is not as exact as a gas exchange test using a mask, but having done two VO2 max ramp tests myself using a mask and used many sports watches, I can say the estimates from the watches are quite accurate.

Why is VO2 max important?

The higher your VO2 max, the higher your level of cardiorespiratory fitness, and if you are a keen endurance athlete improving your VO2 max is likely to equate to improved performances in your events.

It’s not just athletes who benefit from a high VO2 max, however, as it’s also one of the best predictors of long-term health and your longevity, and your risk of cardiovascular disease.

In 2022, a meta-analysis of 37 cohort studies involving 2,258,029 participants, published in the journal Mayo Clinic Proceedings, found that the top third for aerobic fitness, based on VO2 max, had a 45% reduced risk of all-cause mortality compared with individuals in the lowest third for aerobic fitness.

Training regularly will improve your VO2 max, especially if you do a lot of zone 2 low-level aerobic workouts, along with regular interval sessions where you push hard for a short amount of time, recover, and go again.

The exact best way to improve your VO2 max is debated and hard to nail down, but training regularly over a long period of time and getting fitter is the way to go, and that’s obviously good for you in general even if your VO2 max doesn’t immediately rocket up in the way you’d hope.

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Nick Harris-fry
Senior Writer

Nick Harris-fry is an experienced health and fitness journalist, writing professionally since 2012. He spent nine years working on the Coach magazine and website before moving to the fitness team at Tom’s Guide in 2024. Nick is a keen runner and also the founder of YouTube channel The Run Testers, which specialises in reviewing running shoes, watches, headphones and other gear.

Nick ran his first marathon in 2016 after six weeks of training for a magazine feature and subsequently became obsessed with the sport. He now has PBs of 2hr 27min for the marathon and 15min 30sec for 5K, and has run 13 marathons in total, as well as a 50-mile ultramarathon.

He runs 50-80 miles a week and races regularly with his club, which gives him a lot of opportunity to test out running gear: he has tested and reviewed hundreds of pairs of running shoes, as well as fitness trackers, running watches, sports headphones, treadmills, and all manner of other kit. Nick is also a qualified Run Leader in the UK.