A VO2 max test finds the body’s maximum ability to consume oxygen, an indication of physical fitness. Alone, that number may not mean much to anybody other than athletes looking for bragging rights amongst their buddies. (In 2005, Lance Armstrong reportedly had a VO2 max of 85, one of the highest ever recorded.) But from that number, testing centers can estimate your lactate threshold—the point at which muscle fatigue sets in, forcing you to slow down—determine personalized heart rate training zones, and tell you how many and what type of calories, carbs or fat, you’re burning within those zones.
The resting metabolic rate test determines how many calories your body burns at rest, which will help you decide how many calories you need to eat every day to lose, maintain, or gain weight.
Each of these tests can run anywhere between $100 and $250, depending on where they’re done. The catch is that neither of these tests is typically a one-time deal. As you train, your VO2 max and resting metabolic rate can change, altering your training zones and caloric needs, respectively.
So do you need to shell out $100 or more per month for up-to-date metabolic data? Matt Dixon, owner of Purplepatch Fitness and coach to several of today’s top triathletes, doesn’t think so.
“The problem with lab testing is you get a single snapshot on one particular day, then extrapolate that information out for many weeks of training,” says Dixon. While an initial VO2 max test can provide a good baseline, he says, subsequent testing to determine appropriate heart rate zones can be done for free in a field test.
Cyclists, for example, can record their heart rate during a one-hour time trial, while runners can gather heart rate data from a 5 or 10K. Your average heart rate throughout those intense workouts corresponds approximately to your lactate threshold, from which you can determine appropriate heart rate training zones, no expensive retests necessary.
As for your resting metabolic rate, a retest is really only needed if you find yourself struggling to maintain your ideal weight.
Need help mapping your heart rate zones once you’ve found your lactate threshold? Try entering your lactate threshold into this calculator.