What to Know About VO2 Max

Medically Reviewed by Tyler Wheeler, MD on May 02, 2023
3 min read

VO2 max is the amount (volume) of oxygen your body uses while exercising as hard as you can. It's a common tool to understand your fitness level. Knowing your VO2 max can help you train for sports, track your fitness improvement, and improve your heart health. 

When you breathe, you inhale oxygen into your blood. Your heart pumps the blood into your muscles. That oxygen fuels chemical reactions that give your muscles energy. You breathe more quickly and deeply while exercising because your muscles need more energy to work harder. 

VO2 max measures how much oxygen (usually in milliliters) you breathe in while exercising as hard as you can. The more oxygen you inhale, the more energy your body can use. Higher VO2 max usually means better physical fitness. 

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.  Professional athletes usually have higher VO2 max values and goals than the general population.  

Visit a lab. To find out your VO2 max, you’ll likely need to visit a lab or other testing center. You’ll put a mask over your face that captures the amount of oxygen in your breath. While wearing the mask, you’ll run on a treadmill, ride a stationary bike, or perform another exercise as intensely as possible. 

Estimate with math or a tool. If you can’t get to a lab, you can estimate your VO2 max with an equation. Some digital watches and other fitness products predict your VO2 max using your heart rate.  

‌Absolute VO2 max. Your absolute VO2 max is simply the amount of oxygen you breathe in liters per minute. This amount depends on your age, weight, height, and gender.

Relative VO2 max. Relative VO2 max measures your weight in liters per minute per kilogram of body weight. Relative VO2 max is better for comparing different peoples’ fitness levels against each other.

‌Your VO2 max can increase with the right kind of exercise. 

High-intensity training. One of the most effective types of training is high-intensity interval training (or HIIT). 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 of different exercises. HIIT is less effective when you do more than 3 sessions a week.

Low-intensity training. With this type of training, you perform a less intense exercise with fewer or no rest times during the session. Lower-intensity steady-state exercises can include:

  • running
  • biking
  • hiking
  • rowing

Lower-intensity training is slightly less effective than HIIT in increasing your VO2 max. However, you can do it every day since it’s easier on your body.

‌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.

To measure your heart rate, place your index and middle finger under the corner of your jaw, or on your wrist below your thumb. Count how many pulses you feel for a certain number of seconds, like 15 or 20. Then, multiply it by however many times makes a full minute.

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.