Hyrox Training: How to Improve VO2 Max and Drop Your Time
The fastest way to improve at Hyrox is to build your aerobic engine. In the first scientific study of Hyrox athletes (Brandt et al., 2025), VO2 max was the strongest measured correlate of finish time (ρ = -0.71), and the correlation was strongest on the running segments (ρ = -0.73), which account for over half the race. Grip strength and muscle mass showed no significant correlation. Here is how to train your aerobic engine so those numbers move in your favour.
Why Your Engine Decides Your Hyrox Time
The Brandt 2025 study put numbers on something experienced Hyrox coaches have said for years: the engine is the primary limiter. The study measured 11 recreational Hyrox athletes and found VO2 max correlated at ρ = -0.71 with total finish time and ρ = -0.73 with running segment time specifically. Station performance showed no significant correlation, and neither grip strength nor muscle mass was a meaningful predictor.
To understand what those numbers mean in practice: running accounts for roughly 51.2 of the 86.5 minutes in a typical recreational finish. That is more than half the race at running pace. Fading on the fourth or fifth run is not a strength problem and it is not a pacing problem. It is an engine problem. The athletes who hold pace on those later runs are the ones with a higher aerobic ceiling.
Some caveats worth stating plainly: n=11 is a small sample, the correlation design cannot establish causation, and a range-restricted sample of recreational athletes likely compresses the true relationship. The association is real and directionally clear, but it is not a regression that tells you adding 1 mL/kg/min of VO2 max saves you exactly X seconds. The broader coaching consensus agrees with the direction: build the engine first, then stack strength endurance on top.
For context on where your own VO2 max sits relative to your age and sex, see what is a good VO2 max.
Your Engine Has More Than One Gear
Your aerobic system has several trainable components, and they interact.
Aerobic base. This is the foundation, built through zone 2 training: long, easy efforts at a pace where you can hold a conversation. Zone 2 increases mitochondrial density, fat oxidation capacity, and cardiac stroke volume. Without a base, the higher-intensity work does not stick as well and recovery between sessions slows.
Lactate threshold. Your lactate threshold is the highest intensity you can sustain without accumulating lactate faster than you can clear it. A higher threshold means you can run faster before the work becomes anaerobic. In a Hyrox context, this is what determines how hard you can push through a run segment without your legs going acidic before the next station.
VO2 max. Your VO2 max is the ceiling on your aerobic engine, the maximum rate at which your body can use oxygen during exercise. You can improve VO2 max substantially with the right training stimulus. Threshold and base largely determine how much of that ceiling you hold during sustained efforts.
Running economy. How efficiently you convert oxygen into forward movement. Two athletes with identical VO2 max numbers can have meaningfully different race times based on running economy alone.
There is ongoing debate in endurance circles about whether threshold training or VO2 max training drives more performance gain. For most Hyrox athletes who are not already elite, the answer is probably both, sequenced sensibly. The sections below focus on raising the ceiling because that is what the Brandt data points to as the strongest lever.
How to Build It: Raise Your VO2 Max
The most evidence-backed way to raise VO2 max is high-intensity intervals performed at or near your aerobic ceiling. The Norwegian 4x4 protocol is the most studied approach: four intervals of four minutes at 90 to 95% of max heart rate, each followed by three minutes of active recovery. It has the largest body of evidence behind it and maps directly to the kind of sustained high-intensity aerobic work a Hyrox race demands.
For a structured progression, the Norwegian 4x4 training plan outlines how to build toward two quality sessions per week over eight weeks.
Engine-Focused Sample Week
| Day | Session | Notes |
|---|---|---|
| Monday | Zone 2 easy run, 45 to 60 min | Conversational pace, nasal breathing if possible |
| Tuesday | Norwegian 4x4 VO2 session | 4 x 4 min at 90 to 95% max HR, 3 min active recovery |
| Wednesday | Strength, 60 min | Compound lifts, sled, rower; see muscular endurance training |
| Thursday | Threshold or tempo run, 30 to 40 min | Comfortably hard; see interval training for running |
| Friday | Strength, 60 min | Accessory work, ski erg, sandbag carries |
| Saturday | Zone 2 easy run or row, 60 to 90 min | Second base session; keep it truly easy |
| Sunday | Rest or walk | Full recovery |
The Hyrox-Specific Twist: Train Compromised
In a race, every run segment starts from a fatigued state. You step off the ski erg and immediately start running. You finish a wall ball set and start running. Training on fresh legs does not fully prepare you for that.
Add one compromised run per week: immediately after a rowing piece or a sled effort, begin your run interval before your heart rate has recovered. A five-minute row at threshold pace followed straight into a ten-minute tempo run is more specific to race demands than either session done separately. This is the Hyrox-specific adaptation that sits on top of the engine work.
Track It on Your Watch
VO2 max is the most useful trackable proxy for your aerobic engine. Devices like those reviewed in best fitness tracker for VO2 max and the Garmin VO2 max guide estimate it from heart rate and pace data over weeks of training. Apple Watch tracks the same metric through its Cardio Fitness score, and improving your Apple Watch Cardio Fitness score is a direct measure of engine progress.
Realistic targets for recreational Hyrox athletes: a sub-90 finish is very achievable at VO2 max values of 40 to 45 mL/kg/min for men and 35 to 40 for women. A sub-60 finish generally requires values above 50 for men and 45 for women, combined with strong running economy and race-specific conditioning. Single sessions bounce around with sleep, stress, and fueling. The four-week and twelve-week trend lines are what tell you the training is working.
Build Your Hyrox Engine with PEAKVO2
PEAKVO2 runs the Norwegian 4x4 and other VO2 max protocols directly on Apple Watch with continuous heart rate and haptic cues, and tracks your VO2 max trend over weeks so you can see the engine grow.
Download PEAKVO2Frequently Asked Questions
How do I train for Hyrox if I want to get faster?
Focus on your aerobic engine first. The Brandt 2025 study found VO2 max was the strongest correlate of Hyrox finish time, stronger than grip strength or muscle mass. Build two aerobic sessions per week centered on Norwegian 4x4 or similar VO2 max intervals, add zone 2 base, and stack compromised run training (running straight off a rowing or sled effort) to simulate race fatigue.
How do I drop my Hyrox time?
The biggest single lever is raising your VO2 max, which lets you sustain a faster pace through all eight running segments. Add structured high-intensity intervals (Norwegian 4x4 protocol), increase your weekly zone 2 volume, and practice running compromised. Once your engine improves, refining station technique and pacing strategy will add further gains.
What VO2 max do I need for a sub-60 or sub-90 Hyrox?
A sub-90 finish is achievable for most recreational athletes at VO2 max values of 40 to 45 mL/kg/min for men and 35 to 40 for women, combined with adequate station conditioning. A sub-60 finish generally requires values above 50 for men and around 45 for women, plus strong running economy and race-specific preparation. These are estimates based on community data and coaching experience, not the Brandt study itself.
Is VO2 max or lactate threshold more important for Hyrox?
Both matter, and they interact. VO2 max sets the ceiling; your lactate threshold determines how much of that ceiling you can sustain through the running segments without accumulating excessive fatigue. For athletes who are not already aerobically trained, raising VO2 max first tends to have the larger initial effect, but threshold work should follow to translate the higher ceiling into sustainable race pace.
Can I build my Hyrox engine without losing strength?
Yes. The sample week above runs two strength sessions alongside the aerobic work, and research on concurrent training shows strength and aerobic adaptations coexist well when sessions are appropriately scheduled and recovery is managed. The key is keeping total volume manageable and treating the aerobic sessions as the primary stimulus during an engine-building block, rather than trying to peak strength and aerobic capacity simultaneously.
Keep Reading
- Norwegian 4x4 Protocol: The Most Studied VO2 Max Workout
- How to Improve VO2 Max: The Evidence-Based Guide
- Zone 2 Training: The Foundation of Endurance Fitness
- What Is Hyrox? The Fitness Race Explained and What Decides Your Time
- Hyrox Workouts: How to Train the Stations and the Runs