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Your heart rate under the bar

Barbells, dumbbells and machines
OPTICAL

Accuracy

89.2%

Traditional Strength Training Heart Rate Agreement

against an ECG chest strap worn for the same session

Reference standard

ECG chest strap

Sample size

44 participants

Through a weights session the Ultrahuman Ring stays within twelve beats a minute of an ECG chest strap, on average.

Ultrahuman RingECG chest strapbeats per minute
89.2%agreement with the chest strap
11.2 bpmaverage difference
−8.8 bpmthe ring reads low, on average
63–157beats 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.
-60-40-200+2060708090100110120130140150160upper limit of agreement (+22.5)lower limit of agreement (-40.1)average offset -8.8 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.

Weightlifting is the case a ring feels most directly. Gripping a bar tenses the whole forearm, and those contracting muscles press on the small vessels running down into the hand, so the pulse arriving at the fingertip changes shape at the exact moment the effort peaks. The sensor is sitting downstream of the very muscles doing the work.

These are real gym sessions rather than a laboratory circuit, and the shape shows it: your heart rate saws up through each set and drops away through each rest. The Ultrahuman Ring tracks every one of those swings.

What matters through a session like this is whether the peaks land where they belong, because the peaks are what an effort score and a training load are built from.