How VO2 Max Works

To understand the VO2 max formulas, let's first look at VO2, or the difference between the oxygen you breathe in and the amount you breathe out. The difference in oxygen levels between the air you inhale and the air you exhale indicates how much oxygen your body is using.

VO2 is measured in liters of oxygen consumed per minute and may be expressed in units of liters per minute (liters/minute). Your VO2 max is the maximum amount of oxygen your body can use. Since your body weight is used as part of this measurement, the units used are typically milliliters/kilograms/minutes.

The following is the basic formula for calculating VO2 max:

You can calculate VO2 using the following formula:

Do you know the maximum milliliters of oxygen you consume in a minute? Probably not. You can have this measured professionally at some medical facilities and training centers. The test typically involves breathing into an oxygen mask while walking on a treadmill at a certain pace for a certain amount of time. However, this test may be too expensive for the average recreational runner.

Advancements in technology have enabled some fitness trackers to provide VO2 max readings. These can cost anywhere from around $100 to upward of $1,000 or more depending on brand and features.

But you don't need fancy gadgets to calculate your VO2 max. Physiologists and sports scientists have devised other formulas that use factors such as your age, resting heart rate and maximum heart rate to calculate your VO2 max.

Here are two of these alternate formulas for calculating your VO2 max:

Using your resting heart rate and age:

The Rockport Fitness Walking Test (RFWT) using a 1-mile (1.6-kilometer) walk:

Other VO2 max formulas use data from a 3-minute step test or from a 1.5-mile (2.4-kilometer) run-walk test. You can find these formulas along with quick VO2 max calculators online.

Now that you know how to get your VO2 max number, what does it mean? Are you just average, or are you destined to be a world champion?

Your VO2 max indicates how much oxygen your body can use in your current physical shape. Historically, distance runners with a higher VO2 max have been considered to have the most potential for winning races and setting records. Studies over the years have rated different VO2 max values for different age groups, and athletes are consistently within those highest ratings.

In the resources cited for this article, the top-rated VO2 max categories for people in their 20s were 51 and higher for men and 44 or higher for women. As the athletes' age goes up, their VO2 max ranges at each level go down. For example, women in their 50s with VO2 max numbers of 31 and higher are rated excellent, but for women in their 20s, anything under 35 is considered poor. Different VO2 max studies often report different data in different ways, so be sure to look up your VO2 max in multiple resources to compare them and determine a reasonable number for yourself.

Exercise experts have found ways to make the most of the VO2 max number during your training, including ways to push that number higher. The most prominent of these approaches is high intensity interval training, or HIIT. Look for resources on how to develop the HIIT program that's right for you. The following are some HIIT workout formats you might try. Be sure to start with a 10-minute easy jog warmup before attempting these:

Though VO2 max training can boost your running performance and your fitness level, exercise experts across the board say not to make it the only priority in your training. One reason to keep VO2 max in perspective is that there are many factors that you don't have control over, such as your genetics, age and even your altitude [sources: Daley]. In addition, note that some of the top distance runners in the world have had lower VO2 max numbers than some of their less-accomplished competitors, indicating that the VO2 max alone is not a clear predictor of success.