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Why Is VO2 Max Important For CrossFit

Why Is VO2 Max Important For CrossFit

#swolefit | Jul 10, 2018 | 0 comments
  • Post author
    Alix Best

Endurance is perhaps the most important factor that is needed to develop a competitive edge in CrossFit, especially when it comes to speed and power. Improving cardiovascular efficiency, times, performance, speed, strength and agility are crucial key components to becoming a true athlete. And let's not forget the added benefit of optimizing body composition. Improving your VO2max is improving your athletic potential, and isn't that what every CrossFit athlete ultimately desires? 

What Is VO2max?

The cornerstone of clinical and applied physiology in exercise referred to as VO(Volume oxygen) and VO2max (volume oxygen maximum), was defined nearly 90 years ago!

VOis a representation of the limit of the cardiorespiratory capacity. Say wha? Oxygen is essentially the fuel that your body requires in order to use ATP (adenosine triphosphate) to make energy.VO2max is defined as ‘the maximum trained capacity of the pulmonary, cardiovascular and muscular systems to uptake, transport and utilize oxygen (O2) during exercise’. Translation? Oxygen is food for ATP generation that allows your body to continue to exert force during exercise1  

So, you’re saying that CrossFitters should care about VO2 and VO2max ? YES!

VO2max Vs. Cardiovascular Training 

In short, no, they’re related but not the same.

Cardiovascular training is associated with (near) maximum heart rate training and used in hand with a heart-rate monitor in order to avoid burnout/injury (rate at which your heart beats per minute). Cardiovascular Training can also be referred to as ‘zone training’, which might be more familiar, in terms of exercise output percentages. In this type of training you’re able to gauge the minimum, maximum, and somewhere-in-between efforts you’re looking to achieve that training session. It makes sense though, when you think about it, that increased heart rate means increased delivery of blood, oxygen, and nutrients to the areas of your body that need it most. Increased nutrients equal increased output but if you don’t have a whole lot in your gas tank… you’re going to burnout (or injure yourself, or just not be able to go any further).

How is Cardiovascular, or Zone, Training related to 
VO2max training? High VO2max and low resting heart rate go hand in hand when it comes to optimal cardiovascular fitness. Also, the closer you are to your max heart rate zone the closer you are to your VO2max. This positive correlation can be depicted in the same way a car engine works.

Your body is a machine. Your muscles are the engine. Your engine always needs: carbohydrates and fats (act as gasoline/fuel) and oxygen (makes use of the fuel). Your heart is the fuel pump transporting oxygen to the muscles, along with other nutrients, while taking CO2 in return.

Why Is VO2max Important For CrossFit?

The positive correlation between VO2max and cardiovascular training (HRMax) is experienced all the time during interval training, HIIT, and CrossFit! When you’re near your maximum heart rate and near maximum VO2. During interval training, the body relies more on the muscular system and its strengths because it works without free oxygen reaching it. When free oxygen doesn’t have time to reach the muscles, the muscle mass must already have the appropriate energy stores needed to function at an optimal level anaerobically. 

How To Measure Your VO2max

You’re going to need the volume (V) or air that you inhale and exhale as well as the % of oxygen (O2) in the inhaled and exhaled air. Fun fact: the % of O2 in the inhaled air is a known constant, so, the only measuring you have to do is in the exhaled air. Unfortunately, you’re going to need to find some pretty expensive lab equipment and someone who knows what they’re doing (ideally, haha). Typical tests are performed on a treadmill and results are shown in litres per minute i.e. volume of VO2 consumed every minute per kilogram of body mass. The actual equation, for those who are really curious, is

VO2 = [.V x %O2VI] – [.VE x %O2VE].

It’s important to note that finding your exact VO2max isn’t exactly necessary to most athletes. In the event that you’re curious, or are numbers/results orientated, there are many online calculators for you to input information. Having a ball park baseline VO2 max can be ideal for all types of training in Crossfit as well as general health and wellness.2

Increasing Your VO2max For CrossFit

Interval training and HIIT training… well basically high intensity training with rest intervals and lower intensity exercise will get you there. Based on the individual athlete, intervals can always be adjusted, as well as the amount of total training spent close to VO2max rates. Equally, no matter what method of training you choose to do, the more time spent near your VO2max the greater your increases will be. ALL THE FITNESS!

Factors That Will Influence Your VO2max

Just like anything in life, there are a few factors that can influenceVOpositively and/or negatively. Now, please, do not take any of these as an excuse or a handicap, as that is not the intention of including them.4



Ultimately, this is what defines your upper limit because it comes down to your physiology. To a certain extent, this means that your individual circulatory system designed to transport oxygenated blood is different from someone else’s. Yours might be more efficient while another person may be a little slower. Hemoglobin levels come into play as well as the proportion of fast twitch to slow twitch fibers in your muscles. As mentioned previously, slow twitch fibers have the ability to consume more O2 than fast twitch muscle fibers.

Body Composition

Close to all differences observed in a VO2max test are a result of the body mass and body composition of the athlete. Someone with a higher body mass will naturally regulate a higher amount of total oxygen versus someone who has less muscle (muscle consumes more O2 than fat).


Because crossfit combines gymnastics, strength and endurance, a crossfitter will not only need, but require, a higher VO2max than many other sports. This isn’t to say that crossfit is superior to other sports, but just as there are differences in the O2 levels of a sprinter versus a marathon runner, there are differences between crossfit athletes and other athletes. When testing, treadmill tests typically produce the highest VO2max scores.

Fitness Level

In crossfit, an individual athlete has the ability to influence their VO2max based on their fitness level. As an athlete progresses through movements and WODs, not only will their body adjust with strength and endurance, but so will their VO2max . As long as training is consistent and challenging, most of an individual’s VO2will increase in the first 2 months of training. With that being said, most athletes have the ability to increase their VO2max from 5% to 30% in a short amount of time.


Unfortunately, just as anything in life, as we get older, our average VO2max declines :( The negative correlation between age and VO2max isn’t an end all though! It’s important to note that the influence VO2max has on training and fitness is much greater than the influence their age has! Getting old doesn’t have to suck after all. 


Not going to get into this one much, but due to the physiological makeup differences seen in men and women, men genetically have greater size differences and predetermined abilities to contract and build muscles. Like mentioned previously, muscles use more O2 than fat, and if males have more total body mass they naturally will have a higher capability for VO2max levels. 

How Do I Increase My VO2max?

Training with maxVOin mind opens the gate to the field that lays between gymnastics and endurance. The implementation of Nitric Oxide, Kre-Alkalyn, and training forces your body to hit on all cylinders at once over a prolonged period of time or during short bursts as well are all familiar with in AMRAPs and EMOMs. Either way, your Metcon is about to get smashed with speed, power, mental and physical toughness, efficiency of movements, and the cardiovascular capacity of a triathlete with the muscular ability of a gymnast. Talk. About. Ideal. 

Training for incremental progressions in 
VO2max in CrossFit is training with the fundamental scientific principals of top-level conditioning methods that have made the difference in athletes all over the world and at every single level. Science doesn’t have to be complicated, your supplements don’t have to be complicated, and neither does your training. Don’t believe me? 

The Results Will Speak For Themselves

You’ll notice differences in your resting heart rate, blood pressure levels balancing, the ability to hold your breath for longer periods of time, and not to mention you’ll notice yourself breezing through daily Metcons with a vigor and power that wasn’t there before.

Want To Increase Your Endurance And VO2 Max? Kre-Alkalyn is Clinically Proven To Help Increase And Optimize Your Endurance and Improve VO2 Max. Crush Your WOD Today With Kre-Alkalyn


1. Smirmaul, B. P. C., Bertucci, D. R., & Teixeira, I. P. (2013). Is the VO2max that we measure really maximal? Frontiers in Physiology, 4, 203. [Link To Source]

2. Day J. R., Rossiter H. B., Coats E. M., Skasick A., Whipp B. J. (2003). The maximally attainable VO2 during exercise in humans: the peak vs. maximum issue. J. Appl. Physiol. 95, 1901–1907[PubMed]

3. Ekblom B. (2009). Counterpoint: maximal oxygen uptake is not limited by a central nervous system governor. J. Appl. Physiol. 106, 339–341 discussion: 341–342. [PubMed]

4. Bacon, A. P., Carter, R. E., Ogle, E. A., & Joyner, M. J. (n.d.). VO2max Trainability and High Intensity Interval Training in Humans: A Meta-Analysis. Retrieved July 03, 2017, from


  • Post author
    Alix Best

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