Garmin CIRQA Accuracy: Aces Hyrox Sim (Almost)
Sunday is a day of rest for many. Not for me. Today was HYROX Simulation day in the gym. I was a bit short on time and energy, so I kept the time on each station lower and improvised as best I could to replicate the motions of HYROX, albeit at an intensity well below race pace, although I made up for that in yesterday’s CIRQA interval test (didn’t go too well).
Devices On Test
Garmin HRM600 was paired with a FR970 kept in the locker so that a cached session would be retrieved to the watch rather than using the Connect app, as previously CIRQA might have had difficulty when Garmin Connect was live recording another device’s session (i.e. HRM600).
As it was a Hyrox sim, the Amazfit Balance 3 was the obvious choice for one wrist, where on the other I had CIRQA snugly on the lower forearm with Fitbit Air next to it and inverted to ensure CIRQA didn’t slip towards the wrist bone (it didn’t). If Air got a good set of readings in that position, I decided I would keep them in. There was still a possibility of light interference between Air and CIRQA when set up like this, but there was a fair distance between them, so I expected it to be OK, and it was. WHOOP MG was on one bicep, and Polar SENSE still wasn’t syncing on the other.
Test Results
Overall, Garmin CIRQA matched the stronger optical devices.
- vs WHOOP: +1.3 bpm bias, Excellent
- vs Amazfit Balance 3: +0.4 bpm bias, Excellent
- vs Fitbit Air: –1.0 bpm bias, Excellent
All three optical trackers diverged clearly from the HRM 600 (~+8 bpm bias, Fair rating), which suffered a dropout twice during the session.
CIRQA itself showed a visible lag when starting the final wall balls, but its aggregate numbers stayed excellent, and obvious visual errors were limited to that station.
Take Out
CIRQA performed better than I expected in the gym. In fact, it was a good performance considering that several of the exercises involve tight gripping actions, which would affect blood flow and the sensor’s ability to detect the pulse wave.
For the full product listing beyond this gym session, Garmin’s own CIRQA product page covers the rest.
The running elements of the simulation were on a treadmill, showing no signs of cadence lock at this intensity.
Quick answers
How accurate is the Garmin CIRQA against WHOOP, Fitbit Air and Amazfit Balance 3?
In this HYROX gym simulation, CIRQA matched all three within roughly a beat: +1.3 bpm bias against WHOOP MG, +0.4 bpm against the Amazfit Balance 3, and -1.0 bpm against Fitbit Air, each rated Excellent.
Does the Garmin HRM 600 work well during HYROX training?
Not in this session. The HRM 600 diverged from all three optical trackers by around +8 bpm and suffered the same dropout twice, rated Fair overall.
Does the Garmin CIRQA struggle with grip-heavy HYROX stations?
It performed better than expected given several stations involve tight gripping actions, which restrict blood flow and can affect pulse detection. The one clear weak point was a visible split during the final wall balls, typical of optical sensors under strong wrist movement.
Can Garmin CIRQA and Fitbit Air be worn on the same arm without interference?
Yes, with enough spacing. Both were worn on the same forearm in this test, CIRQA snug against the skin and Fitbit Air inverted above it, and no meaningful interference occurred once a fair distance separated the two sensors.
Is the Garmin CIRQA accurate enough for HYROX training?
Based on this gym simulation, yes for heart rate. CIRQA matched three independent optical references within roughly a beat, with the only notable dip coming during the final wall balls station.
Last Updated on 2 August 2026 by the5krunner
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID
