What is VO2 Testing?

In this article we aim to answer the most commonly asked questions we get when it comes to all things VO2 max testing. These will include:

1. What is VO2 max, why is it important and what it tells us about you as an athlete?

2. How trainable is VO2 max (maximal oxygen uptake) and how do you do improve it?

3. Is there a point in getting your VO2 max tested and what do you do with the results?

4. What does a VO2 max test entail, how do I know it is accurate and where can you get tested?

5. What is the difference between lab based VO2 max testing and your smart watch (Garmin, Apple Watch, Coros, Suunto, Whoop etc)?

We will endeavour to answer these questions in the most easy to understand way possible, however if you are interested in more in depth articles, please take a look in our articles section and you will find lots more information on all things training, physiology and nutrition.

What is the meaning of VO2 max and why is it important?

The answer to this is ‘simple'. We require oxygen to produce energy in the form of Adenosine Triphosphate (ATP). The more energy we need; the harder we run, pedal, swim etc. the rate at which we need to regenerate ATP increases and that places a demand on the body to break down storage forms of fuel, and we require oxygen to turn this fuel into ATP.

The more oxygen we can get into the body, the more ATP generation potential we have before our ATP demand starts to outstrip supply. At this point when we need more energy than we can provide, we can create energy without the need for oxygen. Unfortuately at this point we can only work at this effort level for relatively short periods as we start to create an acidic environment in the cell that limits its, and the body’s, performance.

This is why we often combine oxygen uptake testing with lactate testing, as lactate is a proxy measure for how acidic the body is becoming and define different effort zones.

Does this mean that someone with a higher VO2 max is a better athlete?

In general, yes! The more oxygen your body can take on board the more performance potential you are likely to have in endurance sports. However, VO2 max is only one part of the performance puzzle. We have already briefly mentioned another, lactate accumulation and thresholds, and there is another major piece…how efficiently someone uses the type of fuel available in the body and how economical someone is to convert oxygen into movement.

Let’s focus on economy to demonsrate this. Economy is how much oxygen we are using at a given speed or power. When we look at small groups of athletes that are comparable in VO2 max, we might find that VO2 max might be a poor predictor of performance because some people in that group might be more effective at creating power output (running or cycling) at any given level of oxyen uptake.

Think of this like having a two cars with the same size engines but one is more aerodynamic. At the same speed one car is working harder to maintain that speed and is also depleting fuel more rapidly. Even if the other car had a bigger more powerful engine, it still might only be able to reach the same top speed because of its economical deficits and would also run out of fuel much more quickly.

This is why although it is true that VO2 max is a predictor of performance between different levels of athlete in a given sport. When you group athletes more tightly it is not the most important factor in isolation.

So does this mean we shouldn’t care about VO2 testing?

Not at all! We’ll come back to the real value of VO2 testing a little later on in this article.

How trainable is VO2 max?

Before answering this it is important to note that VO2 max is measured in two main ways.

Absolute VO2 max: This the total amount of oxygen the body can take on board each minute and is given in Litres per minute (L/min)

Relative VO2 max: This is the above measure but body mass is factored in to the equation and is given in mL per kg per minute (mL/kg/min).

This is an important differentiation to make because even in those athletes who might not be able to improve their VO2 max in absolute terms, we can assess how improvements in body composition may improve things in relative terms. Although we do not want to chase a low body mass to improve power to weight ratio at all costs, it is important to acknowledge that it does matter in many sports.

It also means that when comparing athletes from different sports, or weight classes within sports, that we need to ensure we are comparing apples with apples before starting to work out if they are fit enough to meet the demands of a specific sport and at what level.

This is where we need to consider not just the size of the engine in the car, but the size of the car and how big the car needs to be. In many sports, having a significant amount of lean mass is important, so we want to find a sweet spot between body mass, endurance, speed, power and strength.

Assuming that we have an athlete who is at their sweet spot in terms of their body composition and other indicators of performance, and is experienced in endurance training, surrounded by a good team and good coaching, then the answer is that VO2 max is not very trainable.

However, if someone has not got an optimal body composition for performance in their sport, has not been well guided in their training and/or hasn’t been gathering feedback and analysis to guide their training. Then even in experienced athletes signficant improvements can be made with the right approach.

In fact, research looking at well trained individuals consistently shows significant improvements in VO2 in some individuals following a number of different training protocols that are designed to improve VO2 max.

What is the purpose in getting your VO2 max tested and how do you use the results?

Testing allows us a window not just into what your numbers are and your athletic performance potential, but we can also idenfity your performance zones to be able to identify strengths and weaknesses in order to target the adaptations that will give you the most improvements of VO2 max and other markers of performance.

VO2 max testing can also be used to detemine things like interval efforts, interval duration and rest periods so that your training is bespoke to your needs. To improve VO2 max, one of the major components people don’t consider is how to maximise their harder effort interval training to maximise time above VO2 max.

We use our testing to work out precisely how long your intervals needs to be, rest periods and duration to create the optimal training stimulus. Most places you will find testing care about giving you a number, perhaps some heart rate zones and nothing else then sending you on your merry way.

This is why on our assessments we work with you to understand your current limitations, training methods and lifestyle to create a bespoke report and recommendations to improve your training and performance.

We can also use oxygen uptake at different intensities and effort levels to work out how your body uses fuel and help you to develop precise fueling strategies using our nutrition expertise.

What does a VO2 max test entail?

The ‘classic’ vo2 max test entails what is known as an incremental test to failure.

This is where you start working at a very easy effort or walking, then every 3 minutes the effort level is increased until you reach what we call volitional failure. Volitional simply means reaching a point where you choose not to continue.

Some people believe this has to be at the point at which they are about to fall off the bike or treadmill with exhaustion, and that is fine if you wish to push yourself to the very limit. However, in reality you will probably have reached your VO2 max limit before this point.

In testing we have some ways of ‘knowing’ you are at VO2 max, such as no further increases in heart rate or VO2 max with an increase in work effort, reaching maximum heart rate and a high level of blood lactate.

For those who are worried about pushing their physical limits then there are some other sub-maximal effort protocols we can use, that may not be as accurate at predicting true VO2 max, but they are accurate enough in order to see basic fitness levels, and to accurately map improvements over time.

How accurate is my smart watch?

The answer to this we will keep short and sweet, the answer is ‘not very’. Whereas testing using our lab set up directly measures oxygen uptake, smart watches use a combination of your fitness data and standard formulas to get an indirect estimate of VO2 max.

This might be useful to track long term improvements in aerobic performance. However, if we are concerned with accuracy to fully profile ourselves as athletes and identify limiters of performance and how to overcome them, as well as other important metrics such as fuel usage, then unfortunately they do fall short.

However, it is also important to note that even (expensive) equipment that proposes to directly measure oxygen uptake can be inaccurate. Unfortunately in the quest for portability and affordability there are now several devices that are available that to the untrained eye look to do the job, but much of this type of tech falls well short in terms of both accuracy and reliability of measurement. This makes them a potentially huge waste of time and most importantly money.

This is why it is important to have testing performed by experts who understand the ‘reality’ of the data and how to extract meaningful conclusions.

For example, we tested and re-tested our equipment and looked at all of the relevant research data that has show that the company that provides our equipment, COSMED, is built to the highest quality, with very high accuracy and consistency when compared to gold standard measurements. They are in our opinion industy leaders in this type of technology.