What is VO2 max and what can it tell me about my health?

There are many ways to measure fitness, from exercise tests to monitoring heart rate and blood pressure. But there’s one metric that stands apart: VO2 max, which provides insight into your aerobic fitness by capturing how well your heart, lungs, circulatory system and muscles work together.

VO2 max measures how effectively your body uses oxygen, in millilitres of oxygen consumed per minute per kilogram of body weight. If your body is able to use more oxygen, that means it’s able to create more energy to power your muscles, explains Stephen Cheung, a professor and senior research fellow in the department of kinesiology at Brock University, who studies exercise and physiology. “For the general population, VO2 max is a very good overall indicator of health.”

VO2 max is “like your engine,” or the amount of work you are able to do, according to Alexandra Coates, an assistant professor and director of the Exercise Physiology and Performance Lab at Simon Fraser University. “It’s highly linked to any sport performance that is aerobic,” she says. But VO2 max isn’t just an important metric for athletes: We all use our muscles for everyday functions, and Coates says the higher your VO2 max is, the easier it is to perform the tasks of daily living such as walking, lifting and moving around.

Plus, the higher your VO2 max, the more oxygen your heart has to power itself. Cheung says a high VO2 max means you’re “generally not going to have things like high blood pressure or plaque build up in your heart.” A 2019 study showed that a high VO2 max, combined with a low resting heart rate, is associated with a reduction in cardiovascular events, such as heart attacks and strokes.

What can affect my VO2 max?

Factors such as genetics, age, sex and fitness level can affect how high your VO2 max is. The measure tends to decline with age and women tend to have lower VO2 maxes than men. Cheung says your VO2 max peaks by your early 30s: “It’s why you see elite endurance athletes, and elite athletes in general, start to slow down as they pass age 30.”

Unfortunately, no matter how hard you train, your VO2 max will drop the older you get. “It’s one of the natural processes of aging,” Cheung explains. “But you can certainly slow down the rate of VO2 max decrease by making sure you are fit and making sure you continue to exercise.”

Exercising more frequently, especially cardio that gets your heart pumping, pushes you to the upper limits of your aerobic limit and over time, your body adapts and your VO2 increases.

How do I know my VO2 max is improving?

The best way to measure V02 max is through testing in an exercise medicine lab. But there are a few easier ways to track improvement.

Most wearables, like Apple Watches or Garmins, track VO2 max. While Cheung says the number these devices provide are only estimates, you can see whether or not the number increases or decreases over time to get a sense of improvement.

Another simple way is to measure how long it takes for you to recover after intense movement. For example, Cheung says to check what your heart rate is before running up a flight of stairs and then measure it again at the top. Then, watch to see how long it takes for your heart to return to its resting rate. As you train, the recovery time should decrease – a sign of improving fitness and increased VO2 max.

What exercises can I do to improve my VO2 max?

Anything that gets your heart pumping and challenges your cardio is a good start. Coates says that if you’re new to exercising, even adding a bit of extra intensity to your walk by going faster or uphill, or opting for stairs over the elevator, can help. For those who are ultra-fit, you’ll need to challenge yourself more – sprint interval training or very high intensity exercises, for example. High intensity interval training, or HIIT, is a popular way to improve your VO2 max since it gets you going extremely hard for a short amount of time, pushing your heart rate and breathing way up.

“Essentially, doing any sort of endurance-type exercise will help improve VO2 max,” she says. Just make sure you’re constantly changing it up: Doing the same stagnant routine won’t lead to better results.

Cheung says that while aerobic exercise is important, it’s integral not to let strength training fall by the wayside. As we age, and our muscles deteriorate. “That’s going to drop your VO2 max because you have less muscles to use the oxygen.”