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The What, Why, and How of VO2 Max Testing
If you have ever been around people who train for endurance events, you may have heard of VO2 Max being mentioned. But do you really know what VO2 max is, why is it important, or how is it tested? In this blog we answer those questions.
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March 11, 2026
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If you have ever been around people who train for endurance events, you may have heard of VO2 Max being mentioned. But do you really know what VO2 max is, why is it important, or how is it tested? In this blog we answer those questions.
What Is VO2 Max?
VO2 max is your body's ability to utilize oxygen, or the maximum Volume of Oxygen used by the body. The higher the number, the better your body can utilize oxygen to clear lactate and other byproducts that form during exertion.
The formula: Max VO2 = heart rate × strokevolume × arteriovenous O2 difference
Heart rate: Number of beats per minute.
Stroke volume: The amount of blood pumped out of the left ventricle every beat or stroke of the heart.
Arteriovenous O2 diff (a-v-O2 diff): This is a representation of how much oxygen was extracted from the blood. The more extracted, the more is used by the body's cells, which is good.
A deconditioned person: High heart rate, low stroke volume, low (a-v-O2 diff) = low VO2 max
A conditioned person: High heart rate, high stroke volume, high (a-v-O2 diff) = high VO2 max
Why is high VO2 max good?
A high VO2 max score means the cells get more oxygen, which is needed to reduce lactate (energy waste) buildup and create more ATP (adenosine triphosphate) energy for your muscles. So you can keep moving at a high rate for longer.
From a health and longevity perspective, a high heart rate during exercise equates to a lower resting heart rate. If your body needs oxygen to survive and continue producing energy for your cells, then more blood flowing through your arteries means more oxygen.
If the heart can pump more blood in one stroke, then it doesn’t have to pump as often. The more it pumps, the harder it works. The more efficient it pumps, the less work it has to do over time.
Think of it as completing repetitions of a back squat to reach a certain weight lifted. If the weight is 100 lbs. and you back squat it 10 times, that is 1000 lbs. lifted over 10 reps. However, when you are stronger and can back squat 200 lbs, you only have to squat 5 times to reach 1000 lbs. In terms of your heart, fewer beats to move the same amount of blood means less work and stress on the heart over time.
When you exercise and intentionally increase your heart rate, more oxygen is delivered to your body, allowing you to produce more energy. The increase in heart rate also makes your heart stronger, so when you are resting, it is easier to pump the same amount of blood with less effort.
So how do you increase your VO2 max score?
A key component of the workouts we do at CrossFit Inguz is based around improving your cardiorespiratory endurance, which in turn translates to a higher VO2 max. So, if you'd like to learn more, visit our "Getting Started" page and contact us today.
How is VO2 Max tested?
Testing VO2 max is done through various means; however, the most accurate method requires a device that can measure oxygen and carbon dioxide entering and leaving your lungs.
Through a series of increasing intervals running on a motorized treadmill, exercise bike, or rowing machine, the difficulty is gradually increased until an all-out effort is reached. Once that effort cannot be sustained, the person stops, and the VO2 max is determined by the computer system.
Testing can be done without a machine in a variety of ways, including measuring heart rate during a particular test. These options are a great way to test yourself if you don’t have access to lab-grade equipment.
At CrossFit Inguz we are partnering with VO Health, a biotech start-up developing a new way to measure fitness and performance through blood-based biomarkers. They are conducting a research study which aims to correlate those blood-based biomarkers with the VO2 max score. If you are a member of CrossFit Inguz and are interested in participating in this study you can see all the details and register through the link below.
Register here: https://vohealth.co/crossfit-inguz
