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Your heart rate at rest

Awake, seated, low movement
OPTICAL

Accuracy

96.7%

Daytime Resting Heart Rate Agreement

measured against an ECG chest strap worn at the same time

Reference standard

ECG chest strap

Sample size

54 participants

Sitting quietly, the Ultrahuman Ring reads within three beats a minute of an ECG chest strap, on average.

Ultrahuman RingECG chest strapbeats per minute
96.7%agreement with the chest strap
2.8 bpmaverage difference
+2.5 bpmthe ring reads high, on average
59–107beats per minute the reference covered in study
Figure 1 — One continuous stretch from a single recording. The figures beside it are for the study as a whole, not for the stretch drawn. Average difference tells you how far a typical reading is from the reference, regardless of whether it is high or low. Average offset tells you the direction of that gap — whether the ring reads high or low, on average.
-8-40+4+860708090100110upper limit of agreement (+6.4)lower limit of agreement (-1.3)average offset +2.5 bpmthe two devices averaged (beats per minute)ring minus chest strap (beats per minute)
Figure 2 — Every five seconds, against the chest strap
One dot is one paired five-second reading, as recorded, pooled across recordings.

Sitting still is not the same as being steady. Even with your hands in your lap, your heart rate wanders by several beats a minute as your breathing, your posture and your attention shift, and a hot drink or a stray thought will move it again. Reading it well means following that wander rather than parking on a plausible number and holding it there.

The trace below is an ordinary quiet stretch. The reference drifts down, settles, then lifts again, and the Ultrahuman Ring goes with it every time. A reading that only holds a number steady looks calm and tells you nothing.

Recovery, Cardio Age, your VO₂max estimate and the way your sleep is scored are all built on heart rate, so how closely it is read carries into each one.