VO2 Max for Hyrox: Build Your Engine

What can training change?

VO₂ max describes maximal oxygen uptake. Training can improve it, but starting fitness, the programme and individual response affect the result. It is misleading to say that half of an individual’s VO₂max is genetic and the other half is available to train.

In the HERITAGE study, 481 previously sedentary white adults from 98 families completed 20 weeks of training. Responses varied substantially. Its heritability estimate concerned variation within that study population; it did not measure each participant’s personal genetic ceiling or the percentage of unused potential. Bouchard et al., 1999.

An interval study, in context

Helgerud and colleagues compared four running protocols in 40 healthy, moderately trained men over eight weeks, with three sessions per week. One group used four 4-minute intervals at 90–95% of maximum heart rate with 3-minute active recoveries. The interval groups improved VO₂max more than the comparison groups in that study. Original trial.

This is evidence for a particular training intervention, not a prescription to add three hard sessions to every HYROX^® week. It does not show that everyone should chase 100% of maximum heart rate, that more weekly hours always produce greater gains, or that trained athletes improve by a fixed percentage each year.

Applying the idea to your week

As a practical planning approach, consider your current running, strength and station workload together. Choose sessions you can complete with consistent technique and recover from. Record interval duration, recovery, pace and perceived effort so later comparisons describe similar work.

A repeatable improvement in running performance can matter even if a watch’s VO₂max estimate barely changes. Avoid reducing body mass just to increase the relative score: changing the denominator is not the same as improving oxygen delivery, and the score is not the sole goal of training.

Questions

Are four 4-minute intervals mandatory?

No. They are one researched protocol, not a universal HYROX^® requirement. Suitability depends on your background and the rest of your programme.

How much will my VO₂max improve?

No fixed annual or eight-week gain can be promised. Use repeated, comparable measurements and training outcomes to assess your response.

Will a higher value guarantee a faster HYROX^®?

No. Aerobic fitness is relevant, but a race also involves station skill, strength and pacing. The measurement guide explains the limits of current HYROX^® evidence.

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Repz recent seasons of race data shows the relationship clearly. Men finishing in under 60 minutes carry an estimated VO2 max of 55+ ml/kg/min.[^6] Women in the sub-65 minute bracket sit in an equivalent relative range. Athletes who plateau in the 75–90 minute zone are frequently limited not by their strength or station technique, but by the aerobic capacity available to sustain pace across the run segments, particularly in rounds five through eight, when the cumulative cost of the race begins to dominate.

Understanding what a given VO2 max score means in practice requires context. The following benchmarks are derived from Repz athlete data and sport physiology norms for functional fitness racing.

For Repz purposes, a VO2 max above 55 for men and above 48 for women places you in the top 20% of finishers: this is the threshold at which athletes shift from "managing the race aerobically" to "racing it tactically." Below these values, the aerobic system is typically the bottleneck. Above them, finish time improvements come more from pacing strategy, station efficiency, and running economy.