What Is VO2 Max? Here’s What You Need to Know About the Longevity Metric (2026)

VO2 max is an intimidating word for an easy-to-understand biometric: it’s about how your body uses oxygen when you push yourself. Short for “maximum oxygen consumption,” it has been the gold standard for assessing cardiorespiratory fitness since the 1950s. Until recently, it was primarily used in research laboratories and elite training centers, helping coaches squeeze every last drop of performance out of elite skiers, runners and cyclists. Today, VO2 max has escaped the labs and gone mainstream, landing on fitness trackers, longevity podcasts, and wellness clinics that promise to put a number on your fitness.

I tested mine last year at the Performance Lab Center in Canyon Ranch, where they fitted me with a heart rate monitor and a tight mask, Darth Vader style, at 8 a.m. After a night of little sleep and no food, the lab tech put me on a treadmill and increased the speed and incline until I couldn’t continue. No music. No hyper-caffeinated instructors shouting positive affirmations. Every few moments the technician would ask me to evaluate my suffering how close I was to the maximum on a scale of 1 to 10.

The test is simple, if slightly sadistic: as the workout intensifies, your oxygen consumption increases until it no longer intensifies. This plateau marks your VO2 max, the upper limit of your aerobic capacity. At the end of my test (just when my patience was running out), I was told my results would come in the next day. Still out of breath, my first thought was that I could have lasted longer. This lingering doubt is part of what makes VO2 max such a maddening and compelling metric.

VO2 Max, explained

Photograph: Peter Schiazza/Getty Images

“VO2 max is an objective measure of how well a human energy system can take in and use oxygen during exercise,” says Elizabeth Gardner, associate professor of orthopedic surgery at Yale University School of Medicine.

Your body still uses oxygen for energy, but VO2 max captures the maximum amount of oxygen your system can use during maximal effort. This is basically what happens when you work as hard as you can. A high VO2 max means your heart and lungs are more efficient at delivering blood to your muscles, and your muscles are better at extracting oxygen from your blood to generate adenosine triphosphate (ATP).

“It’s the best indicator we currently have for premature mortality,” says Malene Lindholm, an exercise physiologist and senior research engineer at Stanford Cardiovascular Medicine. Higher levels of VO2 max are correlated with a lower risk of cardiovascular disease, type 2 diabetes, stroke, and certain cancers. Beyond disease prevention, better cardiovascular fitness is also linked to better sleep, better mood and overall better quality of life.

“It’s especially useful for anyone seriously interested in peak performance and endurance sports,” says Tyler McQuality, associate director of the Center for Sports Innovation at Illinois Tech University. “There are certain intervals you can perform based on pace and VO2 max effort.”