A simple test to measure your aerobic fitness, or VO2max
Maximal oxygen consumption
Maximal oxygen consumption, or VO2max, is the maximal amount of oxygen a person can take in, circulate, and deliver to the body's tissues. Oxygen is an important nutrient, as it is used to produce the energy molecule called adenosine triphosphate (or ATP). The more oxygen a person can take in at a high level of intense exercise the more aerobically fit they are. It is expressed in milliliters of oxygen that is taken in per kilogram of body weight per minute. So, the relative unit of measurement is ml/kg/min.
Measuring VO2max is the "gold standard" for determining aerobic fitness, which is also referred to as cardiovascular or cardiorespiratory fitness. Knowing VO2max is important for athletic performance. Many endurance athletes, such as marathoners and triathletes, prefer to have a high VO2max. In weight lifters, a sufficient level of VO2max supposedly helps speed recovery. However, it is also an extremely important marker of health. Low aerobic fitness is linked to cardiovascular complications and is a poor prognostic indicator if disease is present. Thus, everyone - not just athletes - should know their level of aerobic fitness.
How to measure maximal oxygen consumption
Direct measurement of VO2max requires a maximal exercise test. The test is usually performed on a treadmill or a bike. Other exercise modalities, such as an arm bike, are used for people with a special need. The test is graded, meaning the intensity is progressed continuously from low to maximal level of exertion. The equipment worn during the test - heart rate monitor or electrocardiogram, special headgear, a mouthpiece and a nose clip - can be quite cumbersome. The mouthpiece is connected to a long tube hooked up to machine called a metabolic cart. The cart measures how much oxygen a person takes in. Because of the sophisticated equipment, the test is primarily performed in exercise physiology research laboratories. I have performed these tests for hundreds of subjects across a wide range of fitness levels. They are exhausting, as you have to force yourself to go to failure.
Exercise physiologists from Abilene Christian University perform a VO2max assessment in their Human Performance Laboratory
Like most, you may not have access to an exercise physiology research laboratory. Fortunately, there are several methods to estimate VO2max that can be performed without all of the sophisticated equipment. Though not as accurate as the direct method mentioned above, prediction tests can give a good idea. In this article, I describe a "field" test that is relatively easy to perform. Basically, you run or walk 1.5 miles as quickly as possible. The time it takes to complete the distance is used to predict VO2max from an equation that was developed by scientists.
Please note: If you have any health condition or concerns, please check with your physician before testing your aerobic fitness. Your physician may need to determine whether you are healthy enough to perform vigorous exercise.
1.5 Mile Run/Walk for Time
The 1.5 mile run/walk for time test is a convenient method to predict VO2max. The test was developed from the Cooper Clinic in Dallas TX. It is a very popular field test of aerobic fitness, being used by the military and many athletic teams. In a large meta-analysis, it was the best predictors of VO2max compared to similar walking/running tests . In fact, the authors conclude by stating the following: "When the evaluation of an individual’s maximum oxygen uptake attained during a laboratory test is not feasible, the 1.5 mile and 12 min walk/run tests represent useful alternatives for estimating cardiorespiratory fitness" . The 12 minute test mentioned in the quote is a similar test as 1.5 mile run, though the calculation is slightly more challenging, in my opinion.
To perform the 1.5 mile test, you need the following items:
- A good pair of jogging shoes
- Flat 1.5 mile course - you can track this distance in a neighborhood or find a running course at a local park.
- A calculator
Warm up by walking for 3-5 minutes, but do not include this as part of the test. When ready, hit "start" on the stopwatch and begin covering the 1.5 mile track. Try to complete it as quickly as possible by walking fast, jogging/running, or a combination.
Record the time it took you to complete the distance. Convert seconds into fraction of minutes. For example, if it took 14 minutes and 15 seconds to complete the distance, then that should be converted to 14.25 (14 minutes and 30 seconds would be 14.50). Use the time it took to complete the distance and follow the steps below:
- Divide 483 by your time.
- Take that number and add 3.5.
- That's it - your predicted VO2max
Here is the actual equation : VO2max = (483 / time) + 3.5
As an example, let's say it took you 12 minutes and 45 seconds to complete the distance. That should be converted to 12.75.
- VO2max = (483/12.75) + 3.5
- VO2max = 37.88 + 3.5
- VO2max = 41.38
Predicted VO2max is 41.38 ml/kg.min.
An example of a 1.5 mile run, which was completed in 10 minutes (predicted VO2max = 51.8 ml/kg/min)
What is a "Good" VO2max?
Honestly, you are your only competition. What is good? That depends on where you start. Strive to improve your 1.5 mile run time and VO2max each time you test yourself. And do not worry too much about how you compare to others. There are many factors that determine a person' VO2max. Exercise is very important. But genetic potential mostly accounts for how a person responds to training.
But to give you an idea of VO2max values across different groups:
Elite endurance athletes, like cross-country runners and cyclists, tend to have VO2max values above 70 ml/kg/min. At one time, Lance Armstrong's VO2max was above 80 ml/kg/min. An average, healthy college student has a VO2max between 35 and 45 ml/kg/min. Averages vary between 30 and 35 ml/kg/min for men and 20 and 25 ml/kg/min in women around the age of 50 years. Patients with cardiovascular disease have been shown to have lower values, even in the teens .
Women typically have lower VO2max values at a given aerobic fitness level than men. This is mainly because, on average, women have smaller hearts and lower levels of muscle mass. So comparing across genders is difficult.
How to Improve VO2max
The American College of Sports Medicine  recommends at least 3 days per week of aerobic exercise at a moderate to vigorous intensity.
There are many sophisticated methods to gauge intensity, such as heart rate monitoring. If you would like to monitor your heart rate during exercise, that's great. There are a number of heart rate monitors that allow you to do so with ease. Keep in mind, some are more accurate than others. Do your research before purchasing one.
However, heart rate is not the only method of assessing intensity. You can simply gauge your "ratings of perceived exertion", or "RPE". RPE is basically a scale that rates your exertion level at any given moment. A modified version of this scale is available that ranges from 0 to 10. The higher the number the greater the intensity: think of "0" as no exertion at all, "5" as 50% of your capacity, and "10" is max exertion. A moderate level of intensity is usually between 4-6, while vigorous intensity is 7-8.
Most experts recommend aerobically exercising at a given intensity for 20-60 minutes per session. However, newer research shows the benefit of accumulating smaller bouts of exercise throughout the day. This is good news for people with limited time. Also, you can get a great cardio workout in only 10 minutes.
Rating of Perceived Exertion (RPE) Scale
I recommend performing the 1.5 mile run test every 6-12 weeks. Try to be as consistent as possible. In other words, each time you test you should do so on the same course and as close as possible to the same time of the day. Variations in course terrain or testing time can influence your results and "mask" any actual improvement in aerobic fitness. Changes in the weather can, as well, but that's difficult to control. That said, if you can find an indoor track to perform this test, that may be best. Either way, performing the 1.5 mile run several times throughout the year is a great way to measure your progress.
 Mayorga-Vega, D, Bocanegra-Pamilla, R, Omelas, M, Viciana, J. Criterion-Related Validity of the Distance- and Time-Based Walk/Run Field Tests for Estimating Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis. Plos One 11(3).
 American College of Sports Medicine. (2018). ACSM's guidelines for exercise testing and prescription. Philadelphia: Wolters Klumer, 10th Ed.
 Garber, CE, Blissmer, B, Deschenes, MR, Franklin, BA, Lamonte MJ, Lee, IM, Nieman, DC, Swain, DP; American College of Sports Medicine. Position Stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011; 43(7):1334-1359.