Chest Strap vs Wrist Heart Rate for HYROX: Is a Strap Worth It?

If you train for HYROX by heart rate, the sensor matters. Your watch’s wrist sensor is fine on a steady run, but HYROX is half strength work: sled pushes, carries and wall balls. That’s where wrist heart rate is weakest.

This guide uses published research, manufacturer specs and independent reviews, listed under Sources. Our Amazon links are affiliate links; see our affiliate disclosure.

What the research says

A 2018 study in BMC Sports Science, Medicine and Rehabilitation compared a wrist optical sensor against an ECG chest strap over 371 hours of activity. Overall it was close: an average error of 1.4 bpm. But it varied by activity:

Activity	Average error	Time with a valid reading
Cycling	1.7 bpm	96.0%
Running	2.0 bpm	95.2%
Gym (rowing, cross-training, group classes)	3.0 bpm	92.2%

Gym activities had the lowest coverage and the widest error range of anything tested, with limits of agreement from −17.5 to +19.9 bpm. The authors note gym work was the most varied category, which may explain it.

For HYROX, that matters most at the stations, which look more like gym work than a steady run. A chest strap reads the heart’s electrical signal, and it’s what the study, and reviewers like Coach, use as the reference.

When a strap is worth it

• You train with heart rate zones. Zone 2 runs, threshold work and race simulations are only as useful as the numbers.
• You race or train at altitude. Heart rate runs higher at the same pace, so effort-based pacing matters more. See our HYROX Denver altitude guide.
• Your watch reads oddly in the gym. If your heart rate graph from a simulation looks spiky or flat during stations, a strap is worth trying.

If you mainly track runs and don’t use zones, your watch is probably enough. Our best watch for HYROX guide covers that side.

Polar H10: the accuracy benchmark

The Polar H10 is the strap other devices are tested against. Coach’s Nick Harris-Fry, who uses it as his own benchmark, calls it “the gold standard for accuracy.”

Polar H10
Price	$89.95 list, per Coach’s 2023 review
Battery	CR2025 coin cell, rated up to 400 hours
Connections	Bluetooth and ANT+
Memory	One session, up to 30 hours
Water rating	WR30

Specs from Polar. Coach found real-world battery life shorter than Polar’s claim, replacing the cell every six to eight months. It also notes ANT+ and dual Bluetooth are off by default, the sensor works best with a moistened strap, and the cheaper Polar H9 offers similar accuracy for most people.

Check price on Amazon: Polar H10 · Polar H9

Garmin HRM 600: for Garmin users who want more

The Garmin HRM 600 costs $169.99 and is rechargeable, unlike earlier Garmin straps that took a coin cell. It records activities on the strap for up to 24 hours, and with Garmin watches it adds running dynamics like ground contact time.

In the5krunner’s review, exercise heart rate was accurate across the sports tested, and battery lasted about 30 hours in gym and HYROX-style work, less than for running or cycling. The reviewer called it “the clear choice for anyone who wants a top-tier strap,” but said most athletes won’t need it, and still preferred the Polar H10 for morning heart rate variability readings.

If you own a Garmin Forerunner 970, the HRM 600 also unlocks its Running Economy and Step Speed Loss metrics.

Check price on Amazon: Garmin HRM 600 · Garmin Forerunner 970

Which to buy

You are	Pick
Any watch brand, want the most accurate numbers	Polar H10
On a budget	Polar H9
A Garmin user who wants running dynamics and no coin cells	Garmin HRM 600
Only tracking runs, not using zones	Your watch is fine

Can you wear one in a HYROX race?

Check first. The 2026/27 Singles Rulebook lists what you may wear in section 10.1: knee sleeves, gloves, a weightlifting belt, wristbands, hydration packs and prescribed medical devices. Heart rate straps and watches aren’t on that list or on the forbidden list. The rulebook says “Any item not explicitly listed as permitted is, by default, prohibited,” so ask at check-in before racing with a strap. Our race-day bag checklist covers the rest of the rules.

Either way, a strap’s biggest value is in training, where it makes every zone session and race simulation more accurate.