Most runners and endurance sports athletes know that the higher your VO2 max, the better your cardiovascular fitness and the more “highly trained” you are from an aerobic exercise standpoint.
However, many athletes are not 100% sure exactly what VO2 max is or how to improve VO2 max. How is VO2 max calculated? More importantly, what can you do to increase your VO2 max?
In this article, we will discuss training tips for how to measure VO2 max and how to increase VO2 max for better athletic performance.
What Is VO2 Max?
VO2 max, also known as maximum oxygen intake, is a metric that quantifies your aerobic capacity.
It refers to the maximum amount of oxygen (in milliliters of oxygen in volume) that your body is able to use (oxygen consumption) per minute per kilogram of body weight while running or performing some other form of intense exercise.
The units of VO2 max are milliliters per kilogram per minute (mL/kg/min). So, for example, if your VO2 max is 42 mL/kg/min, it means that when exercising at maximum aerobic capacity, your body can take in and use 42 mL of oxygen per kilogram of your body weight.
Your VO2 max quantifies the maximum rate at which you can take in oxygen (via the respiratory system), transport it to your muscles (through the circulatory system) extract it from the blood, and use it efficiently for aerobic energy production (via aerobic metabolic pathways in the mitochondria in your muscles).
Thus, the higher your VO2 max, the more oxygen you can effectively use during high-intensity exercise through your cardiorespiratory system.
A high VO2 max theoretically enables you to produce more ATP (cellular energy) per minute so your muscles can do more “work” or support faster running or higher-intensity exercise before crossing your anaerobic threshold.
VO2 max is considered to be the gold standard measurement of aerobic fitness.1Habibi, E., Dehghan, H., Moghiseh, M., & Hasanzadeh, A. (2014). Study of the relationship between the aerobic capacity (VO2 max) and the rating of perceived exertion based on the measurement of heart beat in the metal industries Esfahan. Journal of Education and Health Promotion, 3(55), 55. https://doi.org/10.4103/2277-9531.134751
Because your VO2 max is a measure of how much oxygen you are able to take in and use during high-intensity exercise, it is a measure of your aerobic fitness or aerobic capacity (as aerobic means “with oxygen”).
How Can I Measure My VO2 Max?
So, exactly how is VO2 max calculated?
You can measure your VO2 max (maximal oxygen uptake) at an exercise physiology laboratory through a graded VO2 max test (usually on a treadmill or stationary bike).
However, there are also ways to estimate your VO2 max.
Examples of VO2 max estimation protocols include the Rockport Walk Test, the 1.5-Mile Test, the Cooper VO2 Max Test, and the YMCA Cycle Ergometer Test.
Some premium running watches now have algorithms to estimate your VO2 max based on your heart rate, pace, and relative effort level.
Examples include Garmin watches such as the Forerunner 45, 55, 245, 745, and 945, all Garmin Fenix watches, and Garmin Vivoactive 4/Venu watches, which have VO2 max, as does the Polar Pacer.
How to Increase VO2 Max
Even if you are not a competitive endurance athlete, increasing your VO2 max will help you improve your performance during all of your cardio workouts and make aerobic exercise more comfortable at higher intensity levels.
When you think about the elements that are involved in your VO2 max, there are essentially three arms:
- The amount of oxygen you can take in (which is essentially a product of your breathing efficiency)
- The amount of oxygen your heart can deliver to your muscles (which is dependent on how much blood your heart can pump per minute)
- The amount of oxygen your muscles can take up and use effectively to produce ATP through aerobic energy metabolism.
Therefore, to improve your VO2 max, you can target any or all of these three factors in your training.
Here are some tips for how to improve VO2 max:
#1: Do High-Intensity Workouts
Whether you are primarily a runner, cyclist, or another type of endurance training athlete, doing very high-intensity training, such as training around 90 to 95% of your maximum heart rate, is a great way to strengthen your heart muscle and improve the efficiency of your cardiovascular system in delivering2Bruss, Z. S., & Raja, A. (2022, September 12). Physiology, stroke volume. National Library of Medicine; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK547686/ oxygenated blood to working muscles.
Of course, such high-intensity interval training (HIIT) should only be performed about once a week and in an interval-style workout, with low-intensity recovery between high-intensity bouts.
Examples of running workouts would be after a 15-20 minute easy jog warm up, run 10-12 x 400-meter repeats at 90 to 95% of your maximum heart rate, or 6-10 600-meter repeats at a similar workload.
You can also do shorter repeats, such as 200 meters, at this effort level as you build up the endurance and cardiovascular health to handle such a high intensity.
You can do time-based high-intensity interval workouts for cycling or other forms of aerobic exercise. Again, shoot for 90% to 95% of your maximum heart rate effort range.
Start with intervals of 30 seconds, and work your way up to two minutes or so.
Remember that a full two minutes at 95% of your maximum heart rate may not be feasible, even for highly trained athletes. You must drop the interval length to 90 seconds or reduce the intensity closer to 90%.
However, the primary goal should be to stay within 90 to 95% of your max heart rate range, so it is better to shorten your intervals and maintain the desired intensity rather than push for longer at a slightly easier workload.
#2: Add Interval Workouts To Your Training Plan
Studies have found3Bacon, A. P., Carter, R. E., Ogle, E. A., & Joyner, M. J. (2013). VO2max Trainability and High Intensity Interval Training in Humans: A Meta-Analysis. PLoS ONE, 8(9), e73182. https://doi.org/10.1371/journal.pone.0073182 that interval training workouts are often slightly more effective at improving VO2 max than continuous aerobic exercise at a steady state, such as tempo runs.
Your VO2 max interval workouts can be run at a slightly lower intensity (submaximal intensity levels) than the very high-intensity work just described.
For example, any interval-based workouts done at your VO2 max effort level or pace can help VO2 max improvement as a whole.
Variable-paced interval workouts can also be especially effective for increasing VO2 max levels.
Running at your VO2 max pace or exercising at an intensity level that correlates to your VO2 max improves the function of all three aspects (respiration, heart and circulation, and extraction and energy production).
#3: Do Long Runs
As important as it is to incorporate interval training into your workout routine when you are trying to improve your aerobic capacity and endurance, steady-state workouts are also necessary.
Indeed, studies have found4Bacon, A. P., Carter, R. E., Ogle, E. A., & Joyner, M. J. (2013). VO2max Trainability and High Intensity Interval Training in Humans: A Meta-Analysis. PLoS ONE, 8(9), e73182. https://doi.org/10.1371/journal.pone.0073182 that training programs that incorporate both interval workouts, as well as steady-state efforts are the most effective way to improve VO2 max.
Continuous aerobic workouts condition your cardiovascular system by strengthening your heart and lungs and stimulating other favorable cardiovascular adaptations, such as increasing the elasticity of your blood vessels and maintaining a higher blood plasma volume.
Moreover, long runs and other long-endurance aerobic workouts or zone 2 workouts help stimulate the production of new capillaries and mitochondria.
These adaptations, in turn, improve the oxygen uptake and aerobic energy production aspect of your VO2 max.
How Long Does It Take to Improve Your VO2 Max?
The good news is that improvements to your VO2 max are possible at almost any fitness level or level of experience.
However, increasing your VO2 max is definitely a physiological variable that follows the law of diminishing returns.
In other words, the longer you have been consistently running or performing some type of aerobic exercise and the fitter and higher your VO2 max, the slower and less significant your improvements in VO2 max with training will be.
Beginners and untrained individuals can see significant increases in VO2 max after just 4 to 6 weeks of training.
Increases in VO2 max for highly trained or elite athletes are hard-won, and they are typically much smaller, even with highly effective training methods.
This is largely because some portion of your VO2 max is genetically determined,5The Genetics of VO2: What is the impact of endurance genes on VO2 max in athletes? (n.d.). CSFJ. https://csfjournal.com/volume-4-issue-2/2021/10/20/the-genetics-of-vo2-what-is-the-impact-of-endurance-genes-on-vo2-max-in-athletes and there is a relative feeling for VO2 max for all humans, as well as for each individual, based on their own genetics and physiology.
To continue improving your VO2 max, you will need to increase the difficulty of your workouts, either by modulating the intensity itself, the distance or time for the intensity, the overall distance for mileage you are doing, and the frequency of your workouts.
Your cardiovascular system will adapt to the demands of your training program over time, so if you are not progressing in your workout program, you will hit a fitness plateau, and your improvements in VO2 max will stagnate.
To begin including some of these workouts into your running or triathlon training program, you must calculate your maximum heart rate and the rest of your heart rate zones.
There are a few different ways to do so. If you would like to calculate yours, we have a helpful guide from our very own running coach to help you here!