What Is VO2 Max and How Do You Improve It for Better Endurance and Stamina?

If you're serious about training you've probably come across the term "VO2 max." It tends to lie in the vocabulary of seasoned athletes, particularly runners, cyclists and swimmers because it's a measure of aerobic capacity.

Understanding what VO2 max is and how you can use it to your training advantage can improve your performance, but also your quality of life.

But for anyone who regularly exercises, especially if engaging in harder workouts, there's only so much you can do to improve your VO2 max. Here's what the experts have to say.

VO2 max is, in simplest terms, the maximum amount of oxygen your body can use during exercise, explains Krista Rompolski, PhD, associate professor of physical therapy at Moravian University in Bethlehem, Pennsylvania.

Rompolski, an American College of Sports Medicine-certified exercise physiologist and runner, points out that healthy individuals (read: no respiratory illness or condition) cannot improve their lung capacity (their ability to ‌take in‌ oxygen), but they can improve the body's ability to deliver it to the working muscles. People can also improve how much of that oxygen their muscles can use.

Absolute VO2 max is measured in liters per minute, and the only true way to measure it is through a lab test: You'll run or cycle while connected to a machine that measures your expired air, according to Johns Hopkins Medicine. Relative VO2 max adjusts for body mass and is measured in milliliters per kilogram of body weight, Rompolski explains.

If you don't have access to the gold standard test, there are ways you can estimate your VO2 max, explains Judd Van Sickle Jr., head of the Sports Performance and Wellness Program at the University of California, Davis.

• ‌Cooper Test:‌ Participants will run for 12 minutes on a track to cover as much distance as possible. They can then convert their results to VO2 max.
• ‌Beep Test:‌ Participants run 20 meters back and forth keeping time with beeps. At about every minute the time between the beeps get shorter, forcing participants to run faster to cover the distance. Once you've scored your test, you can convert it to your VO2 max.

Van Sickle Jr. also says that the technology on GPS running watches do a better job at estimating VO2 max than you might think.

It's misleading to think that just because you have a "good" VO2 max you'll excel in sport, Van Sickle Jr. says. He gives the example of men in the 20 to 29 age group who might have a VO2 max of 56 (considered "elite") who get blown out by professional athletes.

"They're not even close to being that high level," he says.

But really, there isn't necessarily a "good" or "bad" VO2 max because so much of it depends on genetics, sex and age, Van Sickle Jr. says.

If you want to get a sense of where your VO2 max lies in relation to others, check out the charts below, according to the Cleveland Clinic.

Van Sickle Jr. says a "good" VO2 max is one that allows you to do what you need to do.

"The [general] population's VO2 max is not considered 'good' at large," he says. "Do you have sufficient aerobic capacity to do all the things you want to do? Run a marathon? Walk up a flight of stairs? Good enough for you is meeting all of your needs in the immediate future."

He also points out that as we age, we lose aerobic capacity, just like we lose muscle mass.

"On average, you'll lose 10 percent [of your VO2 max] per decade," Van Sickle Jr. says. So, if you can run a 10-minute mile at max effort at age 30 and you don't do anything to improve that, by age 60, you'll barely be fit enough to walk up a shallow grade, he explains.

For anyone who performs endurance/aerobic exercise at an intense level, it's very difficult to improve your VO2 max, Rompolski explains.

"If you're already athletic, you're pretty close to what you could achieve," she says. "The biggest improvement [in exercise or physiologic adaptation] is going from nothing to something. Athletes are already at a pretty high VO2 max, and it really takes a lot of effort and risk of overtraining to improve beyond that."

In other words, she says, the more fit you are the less room you have to improve. That's because there are a number of limitations on the highest your VO2 max can be, including age, sex, body mass and genetics (a "tremendous" factor, Rompolski says).

Van Sickle Jr. agrees.

"For anybody training seriously for three to four years, your VO2 max isn't really going anywhere," he says. "You can hammer away, but you've probably hit your genetic potential. But biomechanical efficiency and the percentage of your VO2 max that can be maintained for a [certain] distance can be trained."

That doesn't mean all hope is lost, for seasoned or newer athletes. Any workout, really, will improve your body's ability to use oxygen, or at least maintain your current ability.

Rompolski recommends threshold workouts, tempo and Fartlek runs. These require your body to work either at or just shy of anaerobic efforts.

"This will induce adaptations in the muscles and heart that allow you to take up more oxygen at the same intensity," she explains.

Interval workouts are also effective at improving VO2 max and general fitness.

Knowing your VO2 max, or having a rough idea of what it is, can help inform these workouts, Rompolski says, noting that you would work within 80 to 90 percent of your max heart rate.

In maintaining that intensity, she says, you "can't talk and it's difficult to maintain, but you're able to keep it up for more than a few minutes."

Van Sickle Jr. emphasizes the importance of moderate level cardiovascular exercise, too, saying that it's the best thing to do when it comes to improving VO2 max.

Even that "easier" cardio exercise — slower paces, for example — will help your body increase its mitochondrial density, or, in other words, improve aerobic capacity (measured by VO2 max).

In order to gauge improvement of your VO2 max, Rompolski says if you're running a 10-minute mile and your heart rate is 165 beats per minute (bpm) while doing it, and a month later, that same 10-minute mile is at a heart rate of 150 bpm, your heart doesn't have to work as hard.

Your heart not having to work as hard shows your oxygen uptake has improved and your training is having an effect on your VO2 max.