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What is VO2 Max?

Health Adviser and Sports Enthusiast
19 May 2021

These days, there are lots of different ways you can keep track of how active you are and measure your fitness level. You might use a wearable fitness device or collect data on your phone. One way to measure your cardiorespiratory (heart and lung) fitness, is through a VO2 Max test. Here I’ll explain what a VO2 Max test is, how it’s measured and how you can improve your VO2 Max.

What is aerobic fitness?

Aerobic fitness (also called cardiovascular fitness) is your body’s ability to deliver oxygen to your muscles for movement.

Firstly, your lungs take oxygen from the air and transfer it to your bloodstream. From there, your heart pumps the oxygenated blood to your muscles where the oxygen is used, allowing them to contract and work. The more efficient this process is, the fitter you’re thought to be, as you’re more likely to be able to continue that level of work for longer.

What is VO2 Max?

VO2 Max is a scientific way of measuring your aerobic fitness. VO2 Max is the maximum amount of oxygen that your body can use during exercise. It’s measured in millilitres of oxygen taken in and used, per kilogram of body mass, per minute, and is considered one of the best measurements of overall fitness.

Almost 100 years ago, sports scientists discovered that there’s a limit to how much oxygen your body can use, which is different for everyone. This means that, as exercise gets harder, at some point your body will reach the maximum amount of oxygen it can use. This happens even if you continue to make the exercise more difficult.

A number of factors can affect your VO2 Max score, including your:

  • age (VO2 Max tends to decrease as you get older)
  • sex (on average, men have higher VO2 Max scores than women)
  • lung function
  • heart function
  • muscle mass
  • weight / Body Mass Index (BMI)

Why is VO2 Max important?

If you have a higher VO2 Max score, it’s an indicator that you’re fit and healthy. Studies have shown that people with higher VO2 Max scores also tend to have a healthy heart and lungs and may live longer. This is the case even when you take into account other factors, for example if you’re a smoker or have a health condition. This means that VO2 Max scores are a strong predictor of your future health.

Measuring your VO2 Max score regularly and comparing your results allows you to work out the percentage of your VO2 Max that you can sustain over time. This is a useful and accurate way to track improvements in fitness or performance, especially in athletes, rather than using a one-off VO2 Max score alone.

Can you improve your VO2 Max score?

The good news is that you can improve your VO2 Max score. Studies have shown that regular exercise, particularly endurance training (for example, long-distance running), is associated with improved VO2 Max scores.

But more recent evidence suggests that interval training, or high-intensity training (short bursts of intense exercise) could be a more effective way to improve VO2 Max scores. This is compared to running on the treadmill at the same speed for hours on end.

But no matter which type of exercise you prefer, doing any type of regular exercise will increase the efficiency of oxygen transport around your body. This will improve your VO2 Max score.

How is a VO2 Max test performed?

To measure your VO2 Max score, you will be asked do some exercise on a machine while supervised by a healthcare professional. This is usually a treadmill, rowing machine or bike, and the exercise gradually gets harder over time. When doing the exercise, you’ll be asked to wear a heart rate monitor and a mask which is connected to a machine.

The machine collects and measures the amount of oxygen and carbon dioxide you inhale and exhale. Your score is calculated at the point where the amount of oxygen your body uses remains at a steady rate, despite the exercise intensity increasing.

How accurate are fitness trackers at measuring VO2 Max?

There are currently a number of wearable devices and fitness trackers on the market which claim to provide you with a VO2 Max score. However, scientific studies have concluded that commercially available activity trackers are not accurate measures of VO2 Max scores. So, it’s not currently recommended to rely on these devices to measure sports performance or how healthy you are.


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Charlie Dean
Health Adviser and Sports Enthusiast

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