One of the most popular buzzwords in wellness and longevity circles, a metric hailed as the measure of running fitness, VO2max is extremely popular but not extremely well understood amongst those who throw it around.
VO2max is the rate at which your body can take in, transport, and use oxygen during exercise. A practical way to think of it is that your VO2max is your ceiling, an upper limit. It is measured in ml (of oxygen) per kilogram (of you) per minute. A higher VO2max generally means a larger aerobic engine. I say generally because whilst VO2max correlates with race times (particularly shorter races), it is not absolute. For example we would expect a sub-90 half marathon runner to have an effective VO2max of around 51, but the ability to sustain a given percentage of your VO2max relies on other aspects of fitness too so this number could vary quite a bit in either direction. This means it’s possible for a more efficient runner with a lower VO2max to beat a less efficient runner with a higher one.
For a race like a 5km, VO2max is a stronger predictor of race times. A runner with a VO2max of 40 is likely to be around 24 minutes, a runner with a VO2max of 50 is likely to finish in just under 20 minutes, and a runner with a VO2max of 60 would be around 17 minutes. This tighter correlation at shorter distances is because shorter distances require a runner to sustain a high percentage of their effective VO2max (~90-98% depending on speed). This means that a high VO2max means a faster pace.
If you want to see how your 5k time translates across other distances, check out our free calculator.
If you’re racing longer distances, it’s a different story
For half marathons, marathons and ultra marathons many more factors come into play so the absolute ceiling is not quite as relevant (it still correlates, but much more loosely).
Your personal highest VO2max is largely genetic (you can train all you like but once it’s maxed it won’t go higher however hard you train). This is why runners like the Ingebrigsten’s do so much threshold work - years and years of training have maxed out any improvements in their VO2 max so they instead train how long they can sustain higher percentages of it.
When you see people say that the “Norwegian 4 x 4” is the workout, you will understand that it’s only the workout if you have already maxed out every other aspect of your fitness. A balanced training program will help you reach your full potential (and with that your highest VO2max), but chasing a single metric of fitness won’t.
How is VO2max determined and improved?
The major determinants of VO2max include heart size, stroke volume and cardiac output, which are partly genetic, but also very trainable. What we call “peripheral” factors are also important: muscle capillarisation, mitochondrial density and oxidative capacity. Oversimplified, improving these factors improves every aspect of your fitness.
The good news is that lots of different types of training can improve these, not just traditional “VO2 max” sessions. Easy runs can give big gains to newer runners in all these areas.
Untrainable factors include age, sex and genetics. There’s not much any of us can do about these things.
Since we know that the physiological adaptations required to increase your VO2max can be obtained in many ways, a balanced training program is actually the best long term approach to increasing your VO2max. Including some 3-5 minute hard intervals will definitely work, but don’t neglect everything else!
To see how fast you should hit these intervals, and the easy runs in between, check out our free training zone calculator.
Is knowing your VO2max helpful?
Social media and running watches push VO2max as the most important metric. The consequence of this is that some runners try to improve the metric rather than the underlying fitness. You can get your watch to give you a higher VO2 max by running fast 3-5 minute intervals on the track, but unless you’re backing that up with balanced training it won’t necessarily translate to race fitness - or even actual fitness. Chase the fitness, not the metric.
The easiest place to start with a balanced training plan is a 7 day free trial of The Running Algorithm. With no payment details needed, It's a risk free step on the path to perfect training.
