Why? It represents an individual’s maximum capacity for processing oxygen during exercise—loosely analogous to a top horsepower rating for a car.

If your motor produces 350 horses and your rival’s only has a 300 horsepower rating you’re going to blow her doors off, right? The answer is a definite “maybe.” But before examining how VO2 max affects performance, you need to understand how it’s measured and what it represents.

Measuring VO2 Max

The only way to get a true VO2 max reading is to perform a carefully calibrated test in an exercise laboratory. There are loads of VO2 max “calculators” that attempt to predict your score based on a race time or a workout, but those are best-guess VO2 max tests; they’re not the same thing as an actual lab measurement.

The scientifically measured lab version fits an athlete with a mask covering both nose and mouth in order to monitor the amount of oxygen and carbon dioxide that is inhaled and exhaled during a progressively more challenging effort. The maximum score is noted when the oxygen uptake remains constant even though the workload keeps increasing. That redline level signals the end of the test—and often the imminent collapse of the runner onto the lab floor.

Translating Results

The test results are measured in either liters per minute or liters per kilogram of bodyweight. The former represents an absolute measure of aerobic power, while the latter balances that oxygen-processing ability against the athlete’s weight. One of the quickest ways to boost a VO2 max score is to lose a few pounds. However, losing weight can hurt a real-world performance just as quickly. If your VO2 max score goes from 64 to 65, for example, but you soon catch a cold because you crash dieted, or don’t have enough energy to power your run, the real-world results are going to bum you out.

How To Improve Your VO2 Max

For all but the best conditioned athletes who are already at the top of their max, a well-considered schedule of running workouts will reliably lead to improvements. Forget the outdated notion that VO2 max is “genetically determined” and can’t be improved, though some athletes are predisposed to high VO2 max capabilities. All phases of training, from low-intensity base-building sessions to high-intensity intervals, have a positive effect.

Because the test itself is so grueling and seems to hinge on the final few agonizing minutes, many runners think of their hardest workouts as VO2 max-boosters. In truth, upping your max number requires a broad mix of training efforts. It’s true that short, hard intervals often provide the best stimulation when measured over a very short timeframe, but running nothing but max-effort intervals is unlikely to be a successful strategy for the long haul.

Other Factors To Consider

While VO2 max sounds like it should represent the end-all, be-all analysis of an athlete’s potential, there are actually a lot of complicating factors. For one thing, different labs with different testing protocols can produce divergent results. Your score will likely be impacted by what activity is used for the test—running on a treadmill often produces a higher VO2 max score than an equivalent effort performed on a stationary bike.

Still, anyone who has developed a deep passion for quantifying their running abilities is likely to enjoy the process of visiting an exercise lab and testing for VO2 max. Expect to pay $100 to $400 for a single test session—though some labs offer a discount for subsequent tests. If having an exactingly accurate number is less important, those VO2 max calculators (a quick internet search will yield plenty of choices) offer cheaper, and more easily repeatable, options. In any case, keep in mind that no numeric value, be it a VO2 max score or a race time, for that matter, can truly define your running.

The higher the VO2 max, in real-world application, the longer you may be able to hold an intense, anaerobic pace. Other factors, like muscular strength and efficiency and mental fortitude, also play a role in that ability.

All articles are for general informational purposes.  Each individual’s needs, preferences, goals and abilities may vary.  Be sure to obtain all appropriate training, expert supervision and/or medical advice before engaging in strenuous or potentially hazardous activity.