VO₂ max is the maximum rate at which your body can take in, transport and use oxygen during hard exercise. It's the headline figure on every lab report — and the one athletes fixate on. But on its own, it tells you less than you think.
A ceiling, not a destiny
Think of VO₂ max as the size of your engine. A bigger engine raises your potential, but two athletes with identical VO₂ max numbers can perform very differently. What separates them is how much of that ceiling they can actually sustain — and that comes down to thresholds and economy.
The numbers that actually drive training
A good test gives you far more than one figure:
- VT1 / LT1 — the first threshold, the top of your true easy zone. Train below it for your aerobic base.
- VT2 / LT2 — the second threshold, roughly the hardest effort you can hold for ~an hour. This is the number that moves with smart training.
- Economy — how much oxygen you burn at a given pace or power. Better economy means more speed for the same cost.
It's these that we turn into the zones on your training plan — not the headline VO₂ max.
How to read your report
- Look at the thresholds first. Where do VT1 and VT2 fall as a percentage of max? A high VT2 means you can hold a big fraction of your ceiling.
- Track economy over time. Improving economy is often easier than raising VO₂ max once you're trained.
- Compare like for like. Re-test under the same protocol to see genuine change, not day-to-day noise.
So chase a bigger engine if you like — but spend most of your attention on raising the thresholds that decide how much of it you get to use.
