What does your heart rate actually do during a HYROX race?

What does the heart rate trace across a HYROX race look like?

A plateau, reached early. The per-segment figure in the only peer-reviewed measurement of a simulated HYROX race shows heart rate rising steeply from rest through the first run. It levels off at the first station and holds inside a narrow band to the finish. Differences between adjacent segments are a few beats, far smaller than that opening rise. No run stands out, in either direction. The race high is the wall balls, the eighth and final station.

Read the shape, not the individual numbers. The trajectory is what that figure supports; a BPM for any single run isn't.

Coaches' own race analyses agree on the sustained intensity. A published analysis of a competitive athlete's real race describes her at or above threshold for virtually all of it. A Dutch coach's simulation shows a flat pattern across the runs.

The wall balls are the race high, not the final run before them. One published per-segment table has that ordering the other way around, and the figure doesn't support it.

That race was simulated solo in a gym, not run in competition, so treat the shape as the best available picture rather than a law. For what intensity that plateau represents in measured terms, see what intensity is a HYROX race actually run at? For how the two halves compare once pooled, see is heart rate higher on the runs or at the stations?

Why doesn't your heart rate come down when you start running?

Because you never stopped moving. Heart rate falls when the drive to the heart falls, not when the metabolic cost of the work falls. That drive stays up as long as the muscles keep working. In a controlled comparison of recovery from one supramaximal effort, heart rate at the fifth minute was 121.8 BPM after active recovery. Passive recovery put it at 106.2 BPM.

Starting a run off a station is active recovery, not rest. Whether heart rate eases once you settle in is beyond what the published figure can show. It carries one value per segment, not a trace within a run. Coaches do track how quickly it settles, and that practice is covered in how should you use heart rate in compromised-run training?

That gap was measured after cycling, not after a HYROX station, so the direction transfers and the size of it doesn't.

Why does your watch show a spike the study's trace doesn't?

Because your watch reads at the wrist and the race study read at the chest, and the two agree least well in gym work. Measured against an ECG chest strap, a wrist optical sensor ranged from 17.5 BPM below it to 19.9 BPM above during gym work. On running the spread was tighter, 13.7 below to 14.6 above.

Typical accuracy is fine, at a mean absolute error no worse than 3 BPM. It's the outliers that matter, and gym work is where they come from. One landing in a station, or in the first strides after it, is a spike nothing in your cardiovascular system produced.

The peaks in the mid-220s athletes report on race runs sit above any plausible maximum for a recreational athlete. A sensor artifact is the likeliest explanation, though this comparison's spread doesn't by itself reach that far.

How do you lower your heart rate during a HYROX race?

First, pace the first kilometer, because that's where the plateau gets set. Heart rate reaches its plateau by the end of the first run and holds there for the rest of the race. So the opening kilometer is the one segment where the level of the whole race is still negotiable. Go out at a pace you'd be happy holding fresh, and the level you settle at is the one you carry. That's a reading of the shape, not something the study tested.

Second, don't chase the number mid-race. The published figure never comes back down before the finish, so there's little to chase. Third, and this one happens before the race: check whether your device is telling you the truth.

Holding that opening pace is a trainable skill, and it's the same one an easy run trains. You leave the pace alone while it still feels too easy. That's the execution problem RunBeat's Zone Training is built for. It reads your heart rate live and steers you by sound, so you practice holding a target without watching a wrist.

Setting that target for training is its own pair of questions: what is Zone 2 training? covers the range, and should you use max heart rate or heart rate reserve to set your zones? settles which formula it comes from.

Chest pain, dizziness, or anything that doesn't feel like ordinary training discomfort is a reason to stop and see a doctor.