Fitness
Fitness Training
VO₂ Max vs threshold: What are they and which you should train for HYROX
We sat down with HYROX master coach Tiago Lousa to break down the real method to race-day speed, the mistakes holding athletes back and the fixes that make you faster without blowing up.
Whether you're gearing up for your first HYROX race or your tenth, there's plenty to think about – and not just at the start line. How fast should you go out the gate? What’s your fuelling strategy? What’s a realistic pace for each of the runs? Your training blocks leading up to race should also be a vital area of focus, from how many sessions you can stick to each week to improving your overall fortitude.
On the latter, two particular metrics play a huge role both in your training and on race day: your VO₂ max and your threshold. To help understand these concepts more, we recruited the help of HYROX master coach Tiago Lousa, the mastermind behind HYROX world champ Alexander Rončević’s recent run of form.
HYROX master coach Tiago Lousa with his athlete Alexander Rončević
© Filipa Ribeiro @filiparibeiro.lab
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VO₂ Max and threshold: the basics explained
"Your VO₂ max is the maximum amount of oxygen your body can use when you're pushing yourself to the limit," explains Lousa. "Muscles need oxygen to perform, so think of VO₂ max as the size of your engine, measured in liters." VO₂ max training, Lousa continues, "is perceived as very intense, especially during longer intervals of three-to-four minutes.” These sessions, he says, can be quite challenging, even for well-trained athletes such as Rončević – and even Lousa himself.
As for threshold training: "This refers to the highest pace you can maintain without ‘blowing up. It's the point at which your body can clear lactate quickly enough to maintain control. When you exceed this threshold, lactate builds up, causing you to slow down. If you stay below it, you can sustain that pace for a longer duration."
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VO₂ Max and success in HYROX
VO₂ Max is important, but not the deciding factor in HYROX success at all
© Markus Berger/Red Bull Content Pool
In HYROX, VO₂ max matters, but perhaps a little less than many athletes think. As Lousa explains, most competitors only ever look at their VO₂ max displayed on their smartwatch, without realising the number is highly sport-specific. "If Rončević tested his VO₂ max on a treadmill, in a pool, on a rower or bike, he wouldn't get the same score,” he says.
Because HYROX is roughly half running, proper run-specific testing is the only reliable way to understand the metric. Still, Lousa is clear that VO₂ max is just one piece of a much larger performance puzzle. He points to extreme examples like elite cyclist Tadej Pogačar, often cited with a VO₂ max in the 90s. "He would struggle to move HYROX pro weights,” Lousa explain. While triathlete Kristian Blummenfelt, believed to have one of the highest VO₂ max readings ever recorded, doesn't automatically dominate every race he enters.
Lousa also points to a recent experience, where he witnessed the ballet of VO₂ max and threshold first hand. "At a hybrid running camp in Kenya, I trained alongside world-class athletes and coaches. Even these elite athletes find VO2 max training challenging," he says. "Instead, they tend to focus heavily on threshold training and bringing their threshold paces closer to their VO2 max. Their VO2 max values are not off the charts, like one might think, though."
The takeaway? VO₂ max shows physiological potential, not guaranteed output. Strength, power and muscular endurance all carry equal weight and anaerobic threshold – how close an athlete can sit on their VO₂ max for 45 to 60 minutes – is often a more accurate predictor of race performance. Even that only goes so far. "Mindset, pacing, knowing when to push and when to hold back – these subjective factors are huge," says Lousa.
For sustained efforts like HYROX, threshold training is more important
© Christian Pondella/Red Bull Content Pool
In sports like HYROX, 10Ks or half marathons, threshold training is probably the most important performance indicator
A HYROX race, he argues, resembles Formula 1: every car meets the same engine regulations, but tiny characteristics, tactical decisions and the driver's ability determine the result. Likewise, movement efficiency, technical skill and race-craft dictate whether an athlete blows up early or converts their fitness into a winning performance.
About the coach: From the special police forces to renowned HYROX expert
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Focusing on threshold training in HYROX
While VO₂ max often steals the headlines, Lousa is adamant that threshold training is the more meaningful performance marker for HYROX. He's quick to dismiss the idea that it represents some universal 'sweet spot' for overall fitness. Plenty of world-class athletes can be extraordinarily fit, yet display what he calls a "poor threshold", simply because it has little relevance to the demands of their sport.
In HYROX, however, threshold capacity sits at the centre of the performance equation. The race lasts long enough and the intensity stays high enough that the ability to sit close to one's functional threshold for 45 to 60 minutes becomes the clearest indicator of how fast an athlete will actually move through the course. "In sports like HYROX, 10Ks or half marathons, threshold training is probably the most important performance indicator," Lousa explains.
Training with a focus on threshold will really help your HYROX performance
© Philipp Carl Riedl/Red Bull Content Pool
Unlike VO₂ max, which suggests physiological potential, threshold training reflects what an athlete can consistently sustain – how efficiently they can operate under prolonged stress while transitioning between machines, runs and weighted stations. In practical terms, he says, a HYROX athlete should be aiming to hold their threshold pace for the vast majority of the race. The stronger and more stable that threshold is, the more an athlete can push without blowing up, the more room they have to accelerate late and the more reliably their performance matches their training output.
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How to train threshold for HYROX
Lousa's approach to building threshold is designed for everyday athletes training around 8–10 hours per week. The goal is simple: accumulate enough work at (or just below) threshold across different modalities to make that pace feel both familiar and repeatable on race day.
He recommends anchoring your week with two dedicated threshold sessions – one running, one on the static bike – supported by one or two VO₂ max sessions on the ergs. Using the SkiErg or rower for high-intensity work keeps fatigue manageable thanks to the low impact, while running intensity is better handled through hill repeats and strength-focused efforts to protect your legs.
For athletes layering in HYROX-specific sessions, Lousa suggests keeping these close to threshold too. Formats like four minutes on, one minute off EMOMs allow you to accumulate quality work without tipping into the red. A sample HYROX-threshold EMOM he uses himself is below. Repeat for 8–10 rounds at a sustainable, repeatable output:
- 18–20 burpees
- 25m sled push at 100kg
- 18–20 kcal row
- 20 air squats + 15 wall balls
- 1 minute rest
Training for threshold isn't easy, but the benefits show in HYROX comps
© Christian Pondella/Red Bull Content Pool
Building endurance takes time, so make it enjoyable
The emphasis is consistency: the more time you spend training near threshold, the more control you'll have sustaining it under race-day fatigue. As Lousa explains: "threshold sessions are typically longer and designed to simulate race pace. During these workouts, athletes will perform longer intervals with shorter rest periods. The rest time should be significantly shorter than the work interval. For example, if an athlete runs a threshold repetition lasting five to six minutes, the rest should be about one to two minutes - just enough to reset without fully recovering."
Sets can be structured in different ways, advises Lousa. "For instance, four intervals with one minute of rest in between or opt for longer sets, such as 12 minutes of work followed by two to three minutes of rest. In a single session, accumulating a total volume of up to 40, 50 or even 60 minutes. Remember, the goal of these sessions is to prepare for race pace."
The pyramid of fitness
HYROX training: Different exercises build a well-rounded fitness level
© Leo Francis / Red Bull Content Pool
Many HYROX athletes misfire by chasing flashy VO₂ max work before they've built the engine to back it up. Lousa sees the same pitfalls on repeat: athletes guessing their paces, stretching intervals way beyond their capacity, stacking intensity days, or squeezing VO₂ max sets into sessions they were never meant to headline. Threshold work also goes sideways when people run too fast, rest too long, or pepper sessions with so much variation that the 'race pace' effect disappears entirely.
His fix? Start where performance actually begins: the base. "Aerobic capacity and strength are the pillars and everything else sits on top of them," he explains. He frames it as a pyramid: foundation first, then technique and movement efficiency, followed by speed, power and VO₂ max. Only at the very top sits threshold, the layer that directly reflects race pace. "If you skip the bottom, the top won’t hold," Lousa says. Build the base properly and every hard session – VO₂ max, threshold, HYROX-specific grinders – finally starts doing what it's supposed to do: make you faster on the course.
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How to test your threshold
Fitness intensity at Red Bull HYROX Coaches Camp Silverstone 2025
© Leo Francis / Red Bull Content Pool
An accessible method is to monitor your heart rate at a specific pace, says Lousa: "Start with a 20-minute easy run and then reset your watch and run for 30 minutes at a pace close to your threshold, the fastest pace you can maintain for 45-60 minutes, while recording your average heart rate. Perform this test every four weeks at the same pace and observe whether your heart rate decreases over time. If you consistently see a drop in heart rate after a few months, you can increase your pace/speed and repeat the process. Your threshold pace will have improved."
Final thoughts
Lousa's parting advice? "Building endurance takes time, so make it enjoyable. Go out with friends, explore the mountains or the beach, or use a stationary bike while watching documentaries or listening to podcasts. Be sure to respect your easy paces. Remember, the goal is to make it fun rather than difficult."
