What Is VO2max? | Lifehacker
The more you exercise, the fitter you will be. Your VO2max, sometimes described on wearable devices as a “cardio fitness” score, is a number that tends to be higher in people who are in better cardiovascular shape. But it’s not the only measure of fitness, and you need to know what it actually means.
What is VO2max actually (as measured in the laboratory)
Smartwatches and fitness trackers don’t actually measure VO2max; they just estimate he. To actually know your VO2max, you’ll need to go to an exercise lab and do a test on a treadmill or bike while connected to equipment that measures your heart rate and the air you exhale. I did exactly this kind of test to compare my actual VO2max to the numbers reported by nine different devices. You can read about my experience and why it matters here.
VO2max, VO correctly restored2maximum, is the maximum volume (V) of oxygen (O2) that your body can use per minute during exercise, depending on your height, because taller people will naturally use more oxygen. This is considered a good measure of aerobic capacity because, think about high school biology, your body uses oxygen and food to create a usable form of chemical energy called ATP. You then use this ATP to power the movements of your muscles. The amount of oxygen is directly related to the amount of energy produced. Or, in simpler terms, the more you work, the more oxygen you need.
So a person who is very aerobically fit – say an elite marathon runner – can do more work (run faster) than someone who is not. As a result, they will suck in a lot more oxygen per minute during their run than, say, I would.
What is a “good” VO2max?
A typical fit human being will have a VO2max somewhere in the 30s or 40s. If you exercise a lot, you can increase this number. Elite cyclists, skiers, and ultrarunners can have numbers in the 70s or 80s, and a few people have scored in the 90s. I consider myself a recreational athlete (I run a little) and my lab-tested VO2max was 43. Most of my fitness wearables have reported numbers in the 30s or 40s—a good reminder that these estimates can be useful, but they’re not necessarily correct.
Why is high VO2max good?
To be able to use a large amount of oxygen, good lungs are not enough. You also need a strong heart and a healthy circulatory system to carry oxygen to your muscles. And you need muscles that are big and can do a lot of work per minute, which means you’re strong and can do a lot of athletic work. VO2max is a way to summarize many important things about cardio fitness into a single number.
But it is important to know that this number is not All about physical fitness, or even aerobic fitness. First, it doesn’t make much sense to compare your VO2max to other people’s because it is affected by factors like blood volume and muscle mass. Men tend to have a VO2max around ten points higher than similarly shaped women, for example. There are also many aspects of fitness that are not captured by VO2max. Compare two athletes with the same VO2max and you may find that one can continue an endurance race longer than the other. Or one may be better at sprinting while another is better at medium-effort work. One person may be stronger than another, have better technique, or be more resistant to injury.
There is research correlating VO2max with longevity, but that doesn’t mean increasing your VO2max by a few points will add years to your life. Fitness, in general, tends to correlate with longevity and overall health. Scientists who want to study this relationship usually choose one or two things that are easy to measure, like VO2max or grip strength. But in real life, we don’t need to choose a number to maximize; we can work on several aspects of fitness. It’s better to be comprehensive than to focus on a single metric.
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How to measure your own VO2max?
The gold standard is a laboratory test. Top athletes will sometimes take this test if they or their coach want to know their real, definitive VO2max number. But we can measure aerobic capacity in other ways, and there are workouts you can do to get a good estimate of VO2max. If you’re a runner, you can look up a recent race time on this chart to find your VDOT, which roughly corresponds to your VO2max. (My all-time best mileage time earns me a VDOT of 38, for example.)
To estimate your VO2max from a workout, you need something that will take you to your absolute maximum aerobic output. A race does this job well; the same will be true for a test consisting of completing as many laps of the track as possible in 12 minutes. I remember taking a test at a physical education school. a class where we had to climb up and down a high box as many times as possible. These tests aren’t pleasant, but their results can serve as a benchmark to tell you if you’re improving your fitness over time.
How watches measure VO2max
Smartwatches and fitness trackers typically estimate VO2max by comparing your heart rate during exercise to a measure of the amount of work you do during that exercise. Most often this is done while running or walking outdoors. The speed at which you run or walk is measured via GPS and the device compares it to your heart rate. If you can run fast with a low heart rate, you should be in good physical shape and your VO2max will be estimated to be quite high. If your heart rate is high even at a slow running or walking pace, your VO2max is lower.
These estimates are not always accurate. If your maximum heart rate is not set correctly in the device settings, if it’s hot outside, if your running route has hills, or if you don’t get out for running or walking outdoors very often, your VO2max is more likely to be wrong. That said, your VO2max estimate doesn’t have to be exactly correct to be useful. If this number increases over time, you are probably getting fitter. And if it decreases, you will probably lose your fitness.
