What is VO2 max? Here’s how to measure and improve it.

In order to move, think, digest food, and do anything else, your body needs oxygen. This important fact makes VO2 max a useful measure for fitness. It is also extremely useful that some fitness trackers can now offer a VO2 estimate.

Your VO2 max is the amount of oxygen you can use up while exercising. A higher score correlates with greater aerobic fitness, more energy, faster recovery, and better overall health.

We take an in-depth look at how VO2 max is measured, how exactly fitness trackers measure it, and what to do with your numbers.

VO2 max explained

VO2 max is also known as maximal oxygen consumption, maximal oxygen update, or maximal aerobic capacity. The figure shows the amount of oxygen that you can consume in one minute per kilogram of body weight (ml / kg / min).

This in turn means more oxygen supply to the muscles during exercise. This depends on a number of factors: the amount of oxygen you take in with each breath, the arteriovenous oxygen differential (the amount of oxygen that tissues take in from the blood), the number of red blood cells and your maximum cardiac output (Qmax), and more.

VO2 max serves as a predictor of aerobic performance: long distance running and other activities. These activities rely on the aerobic energy system (instead of the phosphagen-lactic acid or ATP-creatine systems). In plain English, you have used up all readily available energy stores in your muscles and bloodstream and you need to start burning fat stores to get more fuel. You can do this indefinitely as long as you maintain a constant pace. This is what we mean by the “fat burning zone”.

The better your VO2 max, the faster you can go without burning out.

However, when you try to run faster and your heart rate exceeds a certain point, you need to return to an energy system based on available energy stores. At this point we feel the gradual build-up of hydrogen in our muscles, which forces us to slow down again. (In truth, we actually use all three energy systems to varying degrees at all times.)

In this way, VO2 max is directly tied to the anaerobic threshold: the point at which we need to switch to anaerobic (less efficient) energy systems. The better your VO2 max, the faster you can go without burning out.

VO2 max is related to the density of the mitochondria. Mitochondria are the cells’ energy factories that are responsible for approximately 95% of your energy needs. These are the worker bees responsible for converting fat, glucose and amino acids into usable energy in the form of ATP.

Also read: The best running watches you can buy

Exercise can cause changes in both the number and efficiency of mitochondria per muscle. If you run a lot for long distances, you will notice an increase in mitochondria, especially in the leg. Rowers may find that they have a proportionally greater amount of mitochondria in their lats / arms. Thus, a rower can achieve a higher VO2 value while rowing compared to running.

Since we also use the aerobic system in everyday activities, it should come as no surprise that better VO2 max correlates with better overall health. For example, a higher VO2 maximum predicts improved brain function. While a correlation is not causal (exercising also improves cognitive function), it can be assumed that more oxygen delivery to the brain could improve performance.

How is VO2 max measured in a laboratory?

As you can probably sense by now, this is quite a complex number to calculate as it depends on many factors. The only way to get a really accurate reading of your VO2 max is to visit a laboratory and undergo an expensive series of tests.

During this test, the athlete is asked to run on a treadmill or exercise bike. They are then gradually pushed until they are completely exhausted. During this time, a technician takes various measurements, e.g. B. Ventilation and oxygen / carbon concentration of inhaled / exhaled air. In other words, they accurately measure the amount of air being taken in and how much oxygen is being removed from that air.

As soon as the oxygen consumption increases constantly, the VO2 maximum is reached. It is an exhausting test!

Fitness trackers and other tools for measuring VO2 max

So how is it that fitness trackers also claim to offer an estimated VO2 maximum?

The most important thing about the VO2 max score generated by your Fitbit or Garmin device is that it is an estimate. However, there are methods of building a rough assessment using simple equations and tests that can be done at home. Fitness trackers use similar methods.

See also: The best fitness trackers

One such method, known as the heart rate ratio method, uses maximum and resting heart rate measurements. This method uses a ratio of the maximum heart rate to the resting heart rate. That number is then multiplied based on factors like age, illness, gender, and so on.

Another test is the Cooper test. This method requires the athlete to run as far as possible within 12 minutes. The VO2 max is then generated based on the distance traveled. The limitations of such methods should be immediately apparent. Even something as simple as leg strength or stride length can have a huge impact on the outcome.

The “beep test” (also known as a multi-step test) is also used to determine an estimated VO2 max. As you may recall from your old exercise class, you need to walk 20 meters back and forth while keeping the beep time.

Finally, the Rockport Fitness Walking Test uses data from a 1 mile run. The heart rate at the end of the walk is used in conjunction with body weight, age, gender and more.

Fitness trackers use similar methods to calculate a rough VO2 max. Most devices that display this data do so only after you’ve worn the device for several runs and walks. From this point on, they can provide a pretty accurate score.

As we have seen, these methods are imperfect. There is no way a fitness tracker can have all of the information it needs to accurately measure oxygen consumption. Most trackers also do not take into account all relevant individual data such as smoking behavior, health status, etc.

What fitness trackers do for them is the sheer volume of data. Because fitness trackers can monitor your heart rate during exercise and rest, and even measure things like stride length, they have plenty of data to generate a useful number. With the help of GPS data and altitude measurements, they were even able to estimate the oxygen content in the area.

Most companies are not particularly transparent about the exact algorithms they use to generate their results.

Unfortunately, most companies are not particularly transparent about the exact algorithms they use to generate their results. This may be due in part to a fear that competitors will be using the same strategies. It is more likely to avoid criticism that might question the validity of your findings. It’s also why companies like Fitbit cleverly use alternate names for these metrics. In this case, Fitbit is referring to a “cardio fitness score”.

In any case, these numbers are still useful to guide your workout. What is more important than accuracy is consistency. As long as the testing method remains the same, you can monitor your progress.

Remember, professional athletes should not rely on such methods to guide their zone training or anything like that. If you fall into this camp, you have most likely already been subjected to real business by your trainer.

What is a “good” VO2 maximum score?

Elite athletes can have VO2 maximum levels of up to 80 ml / kg / min. Conversely, animals like Alaskan Huskies can even reach a VO2 value of over 200 ml / kg-min!

For the rest of us, anything between 30 and 60 is generally considered the normal range. The following table gives you an idea of ​​how to measure yourself:

Age	Male	Female
10-19	47-56	38-46
20-29	43-52	33-42
30-39	39-48	30-38
40-49	36-44	26-35
50-59	34-41	24-33
60-69	31-38	22-30
70-79	28-35	20-25

How can you increase your VO2 max?

Some strategies can improve VO2 max. In general, any form of cardio training has some use in this regard.

HIIT is particularly effective. This is useful when you consider that the protocol involves repetitively “maximizing” your aerobic system. However, steady-state training with low intensity, such as B. jogging, offer unique benefits. This can, for example, improve your Qmax or the quantified maximum cardiac output, which correlates with heart size and strength.

Threshold training is about running as fast as possible without hydrogen building up in the muscles (and lactate increasing accordingly, although this does not lead to muscle fatigue).

In other words, the best way to improve VO2 max is to train at different speeds and thus operate each energy system.