Hyrox Pacing Strategy: Run Below Your Anaerobic Threshold (Here's Why)

Most Hyrox advice tells you to race “at threshold.” Pace the runs at your lactate threshold, hold on through the stations and push the last 2 km. It sounds right but it is wrong for most athletes. The physiology around this and the lactate data are unambiguous about why.

I tested this on myself with two Hyrox simulations and a lactate meter. The first one I ran at my anaerobic threshold pace. After the sled push my lactate was above 8 mmol/L. The run after that, which I held at threshold pace, climbed it to 9. I did not recover until the row where I had to row much slower than normal. The second simulation I ran at my aerobic threshold pace. My lactate stayed under 3 for the entire race. The runs dropped the number every time. I finished with energy left which told me I had run too far below threshold.

The right answer lives between those two extremes and it is closer to the second than the first. For most Hyrox athletes, the running segments should sit below their anaerobic threshold not at it. Here is the physiological reason why, the data that backs it and how to find the right pace for your race.

The two thresholds you need to know

Two numbers govern Hyrox pacing.

Your aerobic threshold is where lactate first rises above resting. Below it, your body produces and clears lactate at the same rate. The top of true easy effort.

Your anaerobic threshold is where lactate starts accumulating faster than your body can clear it. Above this point, you have minutes before performance falls off a cliff.

Why Hyrox is not a steady-state event

A half marathon is a steady state event. Your effort is roughly constant for the duration. Threshold pacing makes sense because the only thing accumulating lactate is the running.

Hyrox is the opposite. The eight stations between the runs are not pauses, they are lactate accelerators. Sled push, burpee broad jumps, wall balls, sandbag lunges, the row, the ski erg, the farmer's carry, the sled pull. Most of these effectively push your physiology above anaerobic threshold for the duration of the station, some catastrophically so. Sled push is often the worst offender.

The running segments are not just running. They are the only opportunity in the race to clear the lactate the stations have just generated. If you run them at or above threshold pace, you won’t clear lactate and the next station probably starts at an even higher level. Soon, you are operating in a state your body cannot recover from inside the race.

The maths is simple. If you start a run at 6 mmol/L (lactate concentration), and you hold a pace that produces lactate at the same rate your body clears it, you arrive at the next station at 6 mmol/L. The next station pushes you higher. You are not running a race anymore, you are surviving.

What happened in my own simulations

I ran two Hyrox simulations, with samples taken at multiple points across the race.

Simulation 1: at anaerobic threshold pace. I held 14.6 km/h on the runs, which is my anaerobic threshold from a recent test. After the sled push my lactate was above 8 mmol/L (high). The subsequent run at threshold pace took it to 9. The next station added to that. I did not bring it down until the row, which I had to row significantly slower than planned to. I finished but I had blown the strategy. My back half splits were 20 to 30 seconds per km slower than my opening pace. The lactate data showed exactly why. Once I was that far above threshold, no amount of pacing trickery on the runs could pull it back inside the race window.

Simulation 2: at aerobic threshold pace. I held 12.3 km/h on the runs, which is my aerobic threshold. Some stations spiked lactate as expected, but it never crossed 3 mmol/L. The runs dropped the number every time. I finished comfortably with energy left, which told me I had run further below threshold than I needed to. The strategy was safe but slow.

The optimal pace for me sits between those two. Closer to the second than the first. Next time I will try somewhere around 14km/h on the runs to let me clear lactate between stations while not leaving energy on the table.

One thing the simulations made clear: heart rate is only partly useful as a pacing tool in Hyrox. Posture and arm position during the stations change your HR independently of your effort. A 165 HR mid-burpee is not the same as a 165 HR mid-run. On race day, pace per km on the runs is easier to control however hard to calculate from the course.

The two athletes I tested, and why their answers differ

Two real examples from athletes I have tested, anonymised.

Athlete A: anaerobic threshold of 14.7 km/h, Hyrox finish time of 65 minutes. His race is closer to a steady state event because it is short enough to sustain a high lactate state. He can run the running segments closer to his anaerobic threshold without catastrophic accumulation because the back half of his race is happening before lactate has had time to overwhelm his clearance capacity. His specific weakness is the sled push, which fatigues him heavily, so he pulls back on the runs immediately afterwards to repay the oxygen debt before the next station.

Athlete B: anaerobic threshold of 11.8 km/h, projected Hyrox finish around 90 minutes. Her event is at least 25 minutes longer than Athlete A's. By the back half of her race, the cumulative lactate load is much higher. She needs to run her running segments meaningfully below her anaerobic threshold, probably closer to her aerobic threshold, for the first half of the race. She is also newer to Hyrox, which means the stations themselves will likely spike her lactate harder than they will for a more practised athlete. Pacing too aggressively on the runs would compound a problem she is already going to face at the stations.

The pattern: the longer your projected finish time, the further below anaerobic threshold you need to run. Sub 60 athletes can run closer to threshold. 90 minute athletes need to be closer to their aerobic threshold.

You cannot feel when you cross your threshold

This is the part most athletes miss. Crossing your anaerobic threshold is silent. There is no breathing change, no leg burn, no signal from your body that you have crossed it. You feel exactly the same on either side of the line.

What you feel is what happens a while after you cross it. Lactate accumulates and your blood becomes an acidic environment. Your breathing pattern breaks and your muscles struggle to contract efficiently. By that point you are already too late! The lactate is built and the stations ahead will keep adding to it. This is why feel based pacing often fails for Hyrox specifically.

The first half of the race is the most dangerous

The most common Hyrox pacing failure happens in the first run. The athlete starts with adrenaline, an inadequate warm up and the visual chaos of the start line. They feel strong. They run the first running segment 30 seconds per km faster than planned.

This is the catastrophic mistake. Because lactate accumulates non linearly, the early debt is the most expensive. An over pacing at the start costs you more in the back half than the same over pacing in the middle would.

The whole first half of the race is danger territory for the same reason. Lactate accumulation in the first 30 minutes determines what is possible in the second 30 minutes. Once you have built a level you cannot clear, the rest of the race is damage control.

Ideally we should pace the first half conservatively. Below anaerobic threshold for the runs, controlled effort at the stations, no heroics. The race is won in the back half but only by athletes whose first half did not lose it.

When you can run closer to threshold

Some factors let you push slightly harder but not at the start of the race. Use them only in the second half once you know how the day is going.

• Caffeine and carb loading. Lift your performance ceiling by a small but real amount.
• Course variations. Some venues have flatter, faster running. The runs themselves cost less, so you have more headroom.
• Adrenaline and mentality on the day. Real but inconsistent. Cannot be relied on as a pacing strategy.
• Doubles. This depends on how the split is structured and the relative thresholds of the two athletes.

How to find your pacing numbers

You cannot work out anaerobic threshold from a race time. Also Hyrox is not a steady state event and the stations contain many variables to take into account.

A lactate threshold test will give you your anaerobic threshold pace, in km/h and HR both based on measured blood lactate during a graded ramp test. Once you have them, the pacing strategy in this post becomes a target you can train and race with.

We are testing an elite Hyrox athlete next week and will publish their full lactate profile and pacing strategy as the follow up to this post. The data should show exactly what an elite level Hyrox profile looks like and how their pacing approach differs from the recreational athlete examples in this post.

Testing for Hyrox athletes in South Wales

We test Hyrox athletes at Team Rees in Caerphilly and KORE Gym in Newport. The 60 minute appointment gives you both thresholds in km/h, the pacing zones for your specific race length.

If you are racing in the autumn season, now is the time to test. Three months gives you enough time to train against the data, refine your pacing and arrive at race day with a strategy that is yours rather than the internet's.

Book a lactate threshold test

For more on what the test gives you, read Do You Actually Need a Lactate Threshold Test? and Why You Blow Up in the Second Half of a Hyrox (And How to Fix It).