If you start reading about training, it won’t be long before you start reading about VO2 max and triathlon. This sounds like a really complicated topic, but it’s not.
What is VO2 max?
Quite simply, it is a measurement of your body’s ability to process oxygen and use it as fuel for exercise. Someone who smokes 20 cigarettes a day and gets out of breath walking up the stairs will have a very low VO2 max, where a professional triathlete would have a very high VO2 max.
VO2 max is measured in litres of oxygen consumed in a minute per kilogram of bodyweight (mL/kg/min). If you can increase your VO2 max score, you will (most likely!) race faster.
How much can it be trained?
The chances are that if you are reading this, you can improve your VO2 max, however there is most definitely a genetic component to someone’s VO2 max that provides a glass ceiling on how much they can improve.
Not many professional athletes will publicly disclose their VO2 max, as they do not want commentators, teammates or competitors to know. If a competitor knows they have a higher VO2 max, they will truly believe they can beat them, which is powerful.
It’s worth pointing out that the highest ever VO2 max was recorded by professional cyclist Oskar Svendsen. Wait, you’ve never heard of him? That’s because neither had I until I did my research for this article. He recorded a VO2 max value of 97.5, which was so high that the scientists had to check the calibration of their equipment.
However, he only won a single race, the junior world championship time trial in 2012. Raw VO2 max numbers are not a good predictor of performance. especially in running and swimming where there is more of a focus on technique and efficiency than outright aerobic output.
How high your VO2 max number can get is largely genetic, however there are many things we can do to train it.
How triathletes train VO2 max
As triathletes, every session we do will improve our VO2 max for triathlon. However, certain intensities will develop it faster than others.
The primary way to build VO2 max is with long, steady training in what we call zone 2. This is the kind of pace a well trained athlete can hold for hours on end. You should be able to hold a conversation in full sentences, albeit with slightly longer pauses between words.
This is a much more effective way to build aerobic fitness than riding hard for an hour. By riding hard we will get fitter, but many of the adaptations will be to muscular endurance. Lots of this training will get your 5K time down and/or your FTP up. However, you will hit a glass ceiling where you cannot get any faster.
This is because your VO2 max is your limiting factor, and you need lots of longer, slower training to improve your body’s ability to inhale large lungfuls of air, which oxygenates the blood, and pumps it to the muscles. The more aerobically fit you are the lower your heart rate will be for a given effort.
However, it’s not all about long, slow distance. We also need to train at the intensity VO2 max.
This is around 105-120% of your FTP, and will feel really, really hard. When you are running, cycling or swimming at your threshold, you feel you are on your limit. You know when you’re going fast, try to squeeze out but more and your body immediately pushes back saying the small increase in intensity is unsustainable? That’s VO2 max.
Most of us can only hold this intensity for 3-4 minutes. This is enough for a final kick in a 10K race, but unsustainable for longer than that.
When I start giving athletes VO2 training we begin with 30 seconds at this intensity. This is enough to really get a burn going, but not long enough to smash us to pieces. The bad news? There is only 30 seconds of rest before the next interval. And the one after that. Followed by the one after that.
When we train at VO2 max our rest intervals should always be equal to our work. Two minute intervals need two minutes of rest, three minutes needs three minutes, and so on.
How to measure and test VO2 max
Most people’s first encounter with VO2 max is when they’re browsing their new Garmin and they find a screen which tells them what their VO2 max is.
Unfortunately, this is a pretty poor estimate of VO2 max. I’m not going to go so far as to say it’s useless, but it is calculated by comparing your running pace or cycling power with the average of those in the same gander and age category.
Athletes who want to really test their VO2 max will do so in a lab. This involves running or cycling wearing a large mask, while following a testing protocol. It’s pretty unpleasant.
The other issue here is that the number you get at the end… isn’t all that useful or important. It’s what we refer to as “gee wizz” data, which is fun to look at, but doesn’t actually influence your training. When you consider you will be paying the best part of £100 for the pleasure of the torture to get this data point, it’s not overly appealing.
If you are in a position where you want, and can afford to re-test every few months to see how your performance is improving then there could be mileage in this to see how you are responding to training. However many athletes do a lab test because they feel they should, and so they can brag to everyone about their VO2 max number. This isn’t a good use of time or money in my opinion.
Garmin says my VO2 max is dropping, what am I doing wrong?
You’re not doing anything wrong, the data it has for you is simply expiring. If you haven’t done any big, maximum efforts recently then the number will drop.
I would however recommend against going out to do a race or FTP test just to update your VO2 max number on your watch, unless there is another reason to do so. The VO2 max number is simply an estimation, rather than a real time indication of your fitness.
Do we even need to measure it?
No, we don’t. At the end of the day, your VO2 max number itself isn’t important. What’s important is that you are improving our aerobic capacity with lots of longer sessions combined with VO2 max intervals.
Aerobic fitness is the single greatest predictor of triathlon success, and often neglected by those who would prefer to go really hard every session and focus on metrics such as FTP rather than what will actually make them faster on race day.
I’d wager that if you are reading this article than you are fairly new to triathlon. In that case, just keep showing up day after day, week after week, year after year. The consistency of training will do far more for your performance than going to a lab.
The best way to boost your VO2 max for triathlon is to follow a structured training programme.
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