What is VO2max, why is it important and how can you improve it?

It's often regarded as the most important metric in endurance sports. But what does it really tell about your physiology?

There are several ways to benchmark one's cycling fitness. It can be done through the direct result of road races and time trials, Strava's KOMs, or – by looking inside your body – through the most used physiological metric in endurance sports: VO2max.

But what is VO2max exactly, and what does it tell professional and amateur riders? How can you measure it, and how can you use it to improve your training structure and ultimately set your PBs and climb up the rankings?

Related: One kilo of carbs a day. What riders ate on hard, Alpine stages at the Giro

What is VO2max?

VO2max is a measurement that indicates the maximum (max) volume (V) of oxygen (O2) your body can take up, transport and use in one minute. VO2max can be expressed in absolute terms (L/min: Litres of O2 consumed in one minute) or relative to an individual's body weight (ml/kg/min: ml of O2 per kg of body weight in one minute).According to some online norm tables, the average score for men between 36 and 45 years old is around 35-38 ml/kg/min (31-33 for women), while an excellent one is above 51 for men and above 45 for women. Top pros, on the other hand, have reportedly been tested in the high 80s and low 90s, including multiple Tour de France winners Chris Froome and Tadej Pogačar, and 60-70 for top female riders

Generally speaking, the more oxygen your body can move to your working muscles, the better your endurance performance. That's why we read a high VO2max value as a good result and a lower one as a less ideal. For example, professional cycling team Bora-Hansgrohe has told us that they use VO2max – among other metrics – to scout talents online. VO2max is an essential piece of the performance puzzle and one that gives a good indication of one's potential in endurance sports. 

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However, that's not the whole story, as we explained when we spoke about cycling economy here. Also, it's important to say that the power you produce when you cycle is not only produced by oxygen (ie, aerobically). For example, in a sprint or when riders are getting into breakaways, the high power wattages produced in a short amount of time are mainly produced anaerobically, using carbohydrates or creatine-phosphate as primary energy sources. That's why another metric called VLmax can help you understand your anaerobic level on top of the aerobic one you can check with VO2max.

Why should you test your VO2max?

“VO2max is one of the key determinants of endurance performance,” explains Kerry McGawley, applied sports scientist and associate professor at the Mid Sweden University. “And oxygen is important for converting fuel that we store in the body,  so carbohydrate and fat, into usable energy. That's the reason that oxygen in itself is so important during exercise.”The other key determinants of endurance performances are fractional utilisation (ie the lactate or anaerobic threshold, or what the FTP is also trying to pinpoint), and cycling economy or efficiency.

“The reason to measure VO2max is that you can see if you’re optimising a standalone, important determinant of performance. But then, at the same time, you would really need to be measuring the other thresholds, and economy. So VO2max it's kind of part of a package.”

Why shouldn’t you measure VO2max?

The reason why you shouldn’t get obsessed with VO2max lies in the fact that the other thresholds are also crucial pieces of the performance puzzle.

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"It's definitely not very useful all on its own,” explains McGawley. “You could have two cyclists standing next to each other, looking identical with quite different VO2max values. And then they would also differ on those other values. What we're trying to do as endurance athletes is to optimise all of those key performance determinants at the same time, which is difficult to do.”

How do you calculate your VO2max?

The best way to calculate your VO2max is through a lab test on a cycling ergometer, a stationary bike that accurately measures power output. The lab protocol is often the most straightforward and brutal you can imagine: you'll start pedalling at a comfortable power and then increase by 10-20 watts every minute until exhaustion. Then, with the help of specialised equipment that measures O2 and CO2 gas exchanges, physiologists can precisely determine your VO2max (providing you really push to your limit, otherwise, the values will be lower).

However, these days, it's also possible to perform a VO2max test outdoors or at home using portable VO2max masks and training software that can estimate it from your power. The protocols to calculate it through masks and software can differ quite a bit, and each has slight variations. We have rounded up the best software for metabolic testing here.

But if you test VO2max at home without the mask (which is quite expensive and a tool mainly for coaches), you will need a power meter and a turbo trainer. If you perform it outdoors – without the mask – it is recommended to perform the protocol on a hill of at least a 6/7% gradient.At the same time, different protocols can give different results. “The power associated with VO2max is really dependent on the test protocol,” explains McGawley. “So if you do a 30-second fast incremental ramp test, compared with a four-minute type of ramp, you're gonna end up having a different VO2max power or power associated with VO2max.”

How do you improve your VO2max?

Although VO2max has an essential root in genetics, it is also highly trainable. There are two main ways to improve it over time. One is by increasing your cycling volumes (long and easy rides, to "bake the cake"). More time spent in the saddle will increase your VO2max and your FTP alike. Alternatively, a shorter way to improve your VO2max is to execute interval training sessions like the one below.

10-15 mins warm-up
8 x (20 sec @ VO2max target, 40 sec easy) into 2 mins easy
8 x (30 sec @ VO2max target, 30 sec easy) into 2 mins easy
8 x (40 sec @ VO2max target, 20 sec easy) into 2 mins easy
15 mins easyWith time, you'll be able to increase the time spent at VO2max to one, two, and even four minutes, but don't forget to be patient and rest well. These sessions are more taxing than they look and need to be performed with a good amount of carbs before, during and after. Carbohydrates are the primary fuel source of these efforts, so don't skip a meal before a VO2max test. 

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However, bear in mind that the impact of any training intervention on your VO2max values also depends on your level of fitness. “If you've got very untrained people, you could do almost anything and you're going to improve their VO2max,” explains McGawley. “But, the more trained someone gets, the more difficult it is to impact their VO2max. And actually, that might not be the parameter that you want to target.”

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