Aerobic capacity: understanding VO2max

A rate, not a fuel tank

Aerobic capacity is commonly used for VO2max, the maximal rate of oxygen uptake. It can be expressed as litres per minute or relative to body mass in millilitres per kilogram per minute. These forms answer different questions; a change in body mass can change the relative number without the same change in absolute uptake.

Oxygen delivery and use involve the lungs, circulation and working muscles. However, a single VO2max value does not describe every adaptation relevant to performance.

Measure and compare carefully

A laboratory exercise test measures respiratory gas exchange while workload increases. The protocol, exercise mode and evidence that maximal uptake was reached matter. Poole and Jones' measurement review discusses why recording a peak value alone does not necessarily establish a valid VO2max.

Field tests and wearable estimates infer aerobic capacity from performance or other signals. They are not interchangeable with a measured laboratory result. For progress comparisons, use the same method and similar conditions; also examine what happened to actual running performance.

What it means for HYROX^®

VO2max, the intensity you can sustain and movement economy interact in endurance performance, as Joyner and Coyle explain. A higher maximum does not guarantee that you will hold a faster pace or perform stations more efficiently.

A 2025 HYROX^® simulation study examined only 11 recreational participants. Its associations are useful research findings, not validated beginner, competitive and elite VO2max requirements for all divisions.

Training and progress

Regular endurance work and appropriately selected harder sessions can develop aerobic performance. The balance should fit your experience and current load. Do not copy an interval study's protocol without considering who was studied and what other training you already do.

The HERITAGE training study found substantial variation in VO2max response among 481 sedentary white adults after 20 weeks. It does not support a guaranteed improvement or deadline for an individual athlete.

Questions

Does a watch value equal a laboratory result?

No. An estimate and a measured gas-exchange result use different methods. Track like with like and consider measurement uncertainty.

Is higher VO2max always a faster race?

No. Sustainable intensity, economy, station skill and other factors also affect performance. A laboratory maximum is one part of the picture.

Is there a required HYROX^® VO2max?

The sources here do not establish a universal entry or performance threshold. Compare progress within your own context rather than assigning race readiness from an invented table.