VO2 Max Testing: How Do You Measure and Improve Your Results?

Medically Reviewed by Jabeen Begum, MD on March 07, 2024
6 min read

VO2 max measures how much oxygen your body uses while exercising. It's a common tool to understand your fitness level. The more oxygen you inhale, the more energy your body can use. Higher VO2 max usually means better physical fitness.  

How does the body use oxygen?

When you breathe, you inhale oxygen into your blood. Your heart pumps the blood to your muscles. That oxygen fuels chemical reactions in your muscle cells that make a substance called adenosine triphosphate (ATP). ATP is the main source of fuel for your muscles during exercise. The more oxygen you can breathe in during exercise, the more energy your muscles have. 


There are two main types of VO2 max measures:

Absolute: Your absolute VO2 max is the total amount of oxygen you breathe in. This amount doesn't depend on your age, weight, height, and gender. It's measured in liters per minute.

Relative: Relative VO2 max is the amount of oxygen you inhale relative to your weight. It's measured in milliliters per kilogram.

Both are a good way to measure your fitness level. Relative VO2 max can be more helpful if you're measuring your results in comparison to other people's.

Your VO2 measures how efficiently your body utilizes oxygen. Knowing your VO2 max can help you measure fitness and heart health improvements over time. VO2 max is especially helpful for athletes like runners, swimmers, cross-country skiers, and rowers to guide their training.

There's no single number that everyone should reach. VO2 max varies from person to person. Your VO2 max depends on things like your:

  • Age
  • Sex assigned at birth
  • Fitness level

Elevation can also make a difference. If you're high up in the mountains, it's harder for your body to take in as much oxygen, which will affect your VO2 max.

You can get an idea of how your VO2 max compares to other people of the same sex and age group using these estimates measured in milliliters per kilogram per minute.

For people assigned male at birth:

Very poor36.735.233.830.927.424.6

For people assigned female at birth:

Very poor30.929.528.225.92422.6

Maximal exercise tests

Maximal exercise tests are used to measure VO2 max when you're exercising at your maximum effort. These are usually done in a lab or other testing center. You’ll breathe into a mask as you run on a treadmill or ride a stationary bike. The intensity of the activity will be slowly increased until you are exercising as hard as you can. The mask is hooked up to a machine that measures your breathing rate and how much oxygen you're taking in and how much carbon dioxide you breathe out. You'll also wear a heart rate monitor. The test normally lasts between 10 and 20 minutes. 

How to prepare for a VO2 max test

  • Wear comfortable athletic clothes and sneakers.
  • Don't do any strenuous exercise 24 to 36 hours before the test.
  • Drink a lot of water in the 12 hours before the test.
  • If your test is in the morning, eat a light snack 1 to 1.5 hours before. If your test is in the afternoon, eat breakfast as usual and have lunch 3 hours before the test.
  • Don't smoke or have alcohol or caffeine 12 to 24 hours before the test.

If you have had an illness affecting your gastrointestinal (GI) system or your lungs within 2 weeks, you shouldn't have a VO2 max test. Make sure to tell the lab about any medications you take as some could affect the results or your ability to do the test. If you have any health conditions, ask your doctor whether or not you should have a VO2 max test. 

Submaximal VO2 max test

If you can’t get to a lab, you can estimate your VO2 max with a simple walking test you can do at home. While this won't be as accurate as lab testing, it can give you a basic idea of your fitness level. You can do this test with or without a treadmill. If you don't have a treadmill, you'll need something to measure distance, such as a fitness watch or using GPS on your phone. To complete the test:

  1. Walk 1 mile at the fastest pace you can. Keep your breathing steady.
  2. When you finish, record the time it took you to finish the mile in minutes and seconds.
  3. Immediately take your pulse by lightly holding the tips of your index and middle fingers against the inside of your wrist just below the base of your thumb. Use a timer on your phone, and count the beats in 10 seconds. Multiply this by 6 to find your beats per minute (bpm).

Next, you can use an online tool like this one to calculate your results and find out your VO2 max.

Other VO2 max tools

Some advanced fitness watches can calculate VO2 max using your heart rate data.

Any type of exercise that gets your heart rate up can help you increase your VO2 max. Some options are:

  • Jogging
  • Cycling
  • Swimming
  • Rowing

The key is to push yourself at least slightly beyond your comfort zone. This challenges your cardiorespiratory (heart and lungs) system. If you haven't been active in a while, even brisk walking might be enough to see improvements. 

High-intensity training 

If you're already in good shape, you might need a bigger challenge. High-intensity interval training (or HIIT) is one of the best ways to boost your VO2 max. To do it, you perform an exercise as hard as you can for a short amount of time, rest for another short period, and then repeat for multiple rounds. An example workout might start with a warmup followed by 1-minute intervals of sprinting and jogging. You can adjust these intervals to make it easier or harder by increasing or reducing the high-intensity interval. 


‌VO2 max is helpful for figuring out your fitness level, but it doesn’t paint the whole picture. Measuring your VO2 max can be expensive, whether you’re going to a lab or using a digital fitness tool. Some other measurements can tell you similar information about your body.

Measure your pulse. Your heart rate, or pulse, is how many times your heart beats per minute. Measuring your heart rate during a workout can guide your exercise plan. Keep track and see how your heart rate changes as you exercise for a few weeks or months. You should see your heart rate decrease even when you're working at the same effort.

Track your progress. If you run, bike, or swim, you can keep track of the speed and distance you’re able to achieve with practice. Consider tracking the number of push-ups, sit-ups, or other exercises you can do in a session over time with practice.

VO2 max is a good way to measure your physical fitness by seeing how well your body uses the oxygen your breathe in during exercise. You can have a test done in a lab to find out your VO2 max, or you can do a walking test at home. Tracking changes in your VO2 max over time can show you how your fitness is improving and how effective your training program is.