Plateau checker
Why is my VO₂ max not increasing?
The number may be wrong, or your training may be in the wrong zone. Answer the questions below to get one main answer and one thing to test for about 3 weeks.
Enter sex and age (or your own max HR) to see your heart-rate zones.
What your VO₂ max number really is
Unless you tested in a lab with gas analysis, your VO₂ max is an estimate. Watches compare your pace (or power) with your heart rate during steady sessions and fit that to a model. Field tests like the Cooper test use a formula. Both are useful for trends, but both can be off by several units.
Why watch numbers plateau
- No qualifying sessions: most watches only update from outdoor runs or rides with GPS and heart rate. Treadmill, indoor and strength sessions often don't count.
- Heat, illness, stress and poor sleep raise heart rate at the same pace, so the estimate drops or stalls.
- A new watch or a reset starts the model over, and optical wrist HR can be noisy.
- Weight: VO₂ max is per kilogram, so extra kg lower the number even if your fitness is the same.
- Training in the grey zone: lots of zone 3 feels productive but often leads to a flat line.
- Real ceilings: with age and many years of training, a stable number can be a good result.
How the zones are set
The checker uses the same system as our heart-rate zones page: your own max HR if you enter it, otherwise 220 − age (men) or 226 − age (women). Zones: Z1 50–60%, Z2 60–70%, Z3 70–80%, Z4 80–90%, Z5 90–100% of max HR.
More: how to improve VO₂ max · VO₂ max calculator · what is VO₂ max?
FAQ
Why is my VO₂ max not increasing?
The most common reasons are that the watch estimate has not updated (too few outdoor sessions with heart rate, heat, illness or a new watch), too much training in zone 3, hard sessions too close together, too little hard work, weight gain, or simply being near your current ceiling.
How long does it take for VO₂ max to go up?
Watch estimates usually move slowly. Give a change in training about 3 weeks before judging it, and look at the trend over months rather than day to day.
Why does my watch VO₂ max stay the same?
Most watches only update the estimate from outdoor runs or rides with GPS and heart rate at a steady effort. Indoor sessions, strength work and very short sessions often do not count.
Is a stable VO₂ max bad?
Not necessarily. For people over 60 or with many years of training, holding the same number over time can be a good result.
Which max heart rate does the checker use?
Your own max HR if you enter it. Otherwise an estimate: 220 − age for men and 226 − age for women. An estimate is less accurate than your own max HR measured in a hard session.