Garmin CIRQA Smart Band Accuracy: Aces Hyrox Sim (Almost)

This is three test sessions from a six-session accuracy series. Read the full review for the complete picture, including where CIRQA fell down.

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 Smart Band interval test (didn’t go too well).

I’ve also added a test result for the following day. Strangely, CIRQA completely failed to auto-detect a 60-minute bike ride, but it did manage to record the yoga session that followed it.

HYROX 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.

Yoga Devices on test

CIRQA was on my right wrist and stayed put well away from the wrist bone. Garmin HRM600 was paired with a FR970 kept at the side of the room. Whoop MG was on my left biceps, whereas my left wrist had both Fitbit Air and Apple Watch Ultra 3.

Garmin CIRQA performed well against the HRM 600 reference in this Flow Yoga session, which felt harder than the heart rate levels show.

• vs HRM 600: +0.8 bpm bias, Excellent (LoA –9.1 to +10.7 bpm, n=3,159)
• vs WHOOP: +1.1 bpm bias, Excellent (LoA –7.1 to +9.4 bpm)
• vs Apple Watch Ultra 3: +0.7 bpm bias, Excellent (LoA –7.6 to +9.0 bpm)
• vs Fitbit Air: +1.6 bpm bias, Good (LoA –1.9 to +5.2 bpm, low n=92)

Average HR was very close to the reference (CIRQA 82.19 bpm vs HRM 600 82.97 bpm). The wider limits of agreement are typical for optical sensors even in low-movement yoga, but the mean bias stayed small, and the overall rating remained Excellent. However, as you can visually see from the chart, CIRQA (red line) is visibly different to the others, perhaps reflecting the impact of movements specific to the right wrist.

Cycling Devices On Test

CIRQA was on my right wrist and stayed well away from the wrist bone, separated by Fitbit Air worn inverted. Tymewear VitalPro was the reference chest strap, recorded on a Wahoo. WHOOP MG was on my left bicep in a sleeve. Polar LOOP 2 and Amazfit Helio Strap were on my left wrist, with the Helio Strap nearer the wrist bone.

Chart colour key: black = Tymewear VitalPro (reference), red = Polar LOOP 2, blue = Garmin CIRQA, green = Fitbit Air, yellow = WHOOP MG.

Overall, Garmin CIRQA tracked the Tymewear VitalPro chest-strap reference accurately across the ride.

• vs Tymewear VitalPro: +1.1 bpm bias, Excellent (LoA –17.1 to +19.3 bpm, n=5,311)
• vs Amazfit Helio Strap: +0.5 bpm bias, Excellent (tight LoA)
• vs WHOOP MG: +0.5 bpm bias, Excellent (tight LoA)
• vs Fitbit Air: –1.3 bpm bias, Excellent
• vs Polar LOOP 2: –2.6 bpm bias outbound, +0.6 bpm bias return (split legs after a mid-ride stop)

The chart revealed one significant under-reading period from CIRQA plus two smaller under-reads near the start. Polar LOOP 2 showed visually significant differences on the chart despite its modest aggregate bias. The other devices aligned closely with the reference once the split legs were combined.

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. Although visibly different, the HR lines on the yoga chart were close enough to have little impact on any of Garmin’s follow-on metrics (load).

For the full product listing beyond these gym sessions, 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 19 August 2026 by the5krunner