I tested the Garmin Cirqa against a chest strap to see if its heart rate sensor is accurate — here’s the results

Garmin Cirqa.

The heart rate sensor on the Garmin Cirqa screen-free tracker powers pretty much all the important stats you get from the device. It’s key to sleep tracking, your body battery and training readiness scores, and your heart rate variability readings.

So it must be accurate, especially as, unlike with the best Garmin watches, you can’t pair an external heart rate monitor to the Cirqa to get more accurate data if required.