Here’s everything you need to know about the ultimate measure of fitness—and how to boost yours

The burn. The Bane mask. The bleak possibility of being waterboarded by vomit.

Whether you’ve wheezed through one first-hand, or cocked a cautious eyebrow from afar, more and more men are learning of the unique sadism that is the VO2 max test.

Championed by experts as the gold standard for measuring aerobic fitness, the lab-administered V02 max exam sees athletes and average guys alike pushed to the literal brink—hence the prevalence of puke—something that, in turn, provides a window into their capabilities.

Knowing your V02 max—and how to upgrade it—could be your most valuable asset in gradually improving your fitness and performance over time.

WHAT IS V02 MAX?

This is all well and good, but with us humans (sadly) limited in how much oxygen we can take in, there exists a ceiling. That, right there—your ceiling, as it stands right now—is your VO2 max.

“The definition, precisely, is the volume of oxygen consumed per unit of time,” says Bradley Elliott, Ph.D., lecturer of physiology at the University of Westminster. “It’s aerobic metabolism—your ability to take oxygen, metabolise it, and turn it into energy—and the rate at which you can do that.”

Measured by millilitres of oxygen per kilogram of body mass per minute (ml/kg/min), the loose average for men hovers between 40 and 50, with elite athletes boasting figures of 60 or more. Lance Armstrong was known to have a VO2 max of 84 ml/kg/min, whereas in 2012 Norwegian cyclist Oskar Svendsen reportedly scored a world-record 97.5.

HOW IS V02 MAX MEASURED?

Best administered with the relevant equipment—runners on treadmills, cyclists on bikes, and so forth—the subject is lulled into a false sense of security by starting off with an effortless walk (or pedal or row) while attached to a breathing mask.

“That mask measures everything that comes out of your mouth,” says Elliott. “The rate of air that’s coming out—so, the volume—and also what it’s made up of.”

Pleasantries over, the test progressively becomes more evil.

“Every two or three minutes we’ll make it a little bit harder, then a little bit harder, then a little bit harder again, and harder and harder and harder, until it comes to a crashing halt where they cannot maintain that effort.”

The point of exhaustion is crucial, as this is where the VO2 max data is extrapolated. “That plateau is a pretty good sign you’ve reached your maximum,” Elliott says. “You are not producing any more energy from an aerobic performance point of view.

“[Vomiting] is not always necessary, but it does help ensure you’ve hit your maximum,” he says.

“That being said, I don’t really like cleaning vomit out of my mask or treadmill.”

HOW MUCH DOES YOUR V02 MAX ACTUALLY MATTER?

It boils down to how important performance is to you.

VO2 max is acknowledged as a foolproof measure of an athlete’s physiological ability, and improving it is a sure way to advance your athletic performance much like improving your strength or speed would. But no sport awards prizes to the athlete with the gnarliest lungs.

Form, stamina, endurance, and mental fortitude are all key factors in an individual’s performance, with VO2 capabilities just another marker—itself impacted by genetics as much as hard work.

So when the Tour de France next rolls by, let Chris Froome’s form and trophy cabinet guide your gambling—not his 88.2.

As José González-Alonso, professor of exercise and cardiovascular physiology at Brunel University, succinctly puts it: “VO2 max is just an indication—it’s not a good predictor of performance.”

IS V02 MAX RELEVANT TO YOU?

VO2 max is all about converting oxygen to energy for a sustained period of time. As such, it’s more tortoise than hare.

“As a rule of thumb, the longer the sport, and the more muscle mass that’s involved—those are the athletes that will have high VO2 max values,” says Elliott. For those athletes—and you, if you’re one of them—V02 max awareness can be extremely valuable.

“Cross country skiers and triathletes have ridiculously high VO2 max scores, because not only do they use their lower body like a runner or cyclist, but they also use their upper body and work very closely to their physical maximum,” Elliott says.

Keep in mind, VO2 is known as the gold standard of aerobic fitness. Sure, an elite sprinter or weightlifter wouldn’t mind a supernatural VO2 value, but it is irrelevant to their sport—contested at high intensity, in short bursts, and strictly anaerobic in nature.

In other words, improving your V02 max won’t allow you to lift more, jump higher, or run faster.

HOW CAN YOU IMPROVE YOUR V02 MAX?

Though it is somewhat hardwired in your DNA, you can upgrade your VO2 max value—and it may even come with some side health benefits.

According to Elliott, those with a higher VO2 max “tend to live longer,” with studies showing an inverse relationship between V02 max and people’s risk of developing cardiovascular disease, stroke, type 2 diabetes, and obesity.

So, how do you improve your V02 max? As with many modern fitness quandaries, the answer lies in high-intensity interval training (HIIT). Here’s a great HIIT workout that doesn’t require any equipment.

“HIIT will improve your VO2 max really quickly,” says González-Alonso. “Within a couple of sessions, you can acutely do that. But, in practical terms, it is important to balance the amount of intense training you do with lower-intensity training. You can get injured quickly if you just do intense training when your body is not adapted.”

For the sole ambition of boosting VO2 max, Elliott prescribes two high-intensity sessions a week, “intermingled with two or three longer, lower-intensity, recovery-type sessions—a Sunday [bike] ride with your friends, perhaps.”