VO₂ max: oxygen uptake and HYROX performance

What the number measures

Oxygen uptake can be reported in litres per minute or relative to body mass in millilitres per kilogram per minute (mL/kg/min). These answer different questions. For example, 3.5 L/min at 70 kg equals 50 mL/kg/min. A change in body mass can change the relative value without an equivalent change in absolute oxygen uptake.

Oxygen delivery and its use by working tissues both matter. Heart rate alone cannot provide a direct VO₂ max measurement. Poole and Jones explain laboratory measurement and the importance of verifying that a maximum has actually been reached.

Measured values and estimates

A laboratory test analyses breathing gases while exercise becomes progressively harder. A plateau in oxygen uptake can support identification of a maximum, but it is not observed in every incremental test. The protocol and any verification stage matter; ask what the reported result represents.

A watch or running field test estimates VO₂ max using a model. It does not directly measure respiratory gases. There is no single accuracy percentage that applies to every device, person and test. Compare repeated results using the same method and similar conditions, rather than interpreting a small change across devices as a fitness gain.

What HYROX^® research shows

In a 2025 study, 11 recreational athletes completed an Individual Open simulation; eight were men and three were women. Higher measured VO₂ max was associated with faster completion. This small observational study supports the relevance of aerobic fitness, but does not establish universal male/female cut-offs for sub-60 or sub-75 finishes. Brandt et al..

Station strength, movement skill and pacing still affect the result. An association is not proof that increasing one athlete’s VO₂ max by a specified amount will reduce their race time by a predictable amount. See VO₂max training and lactate threshold.

Questions

What is a good VO₂ max for HYROX^®?

There is no validated universal qualifying value. Interpret your result using the test method, personal context and actual training performance.

Is a watch reading a laboratory measurement?

No. It is an estimate, even when the display looks precise. Use it as one source of information rather than a race prediction.

Can a high VO₂ max coexist with a slow race?

Yes. Aerobic capacity does not measure your ability to execute every station, manage transitions or choose a sustainable pace.