How Skin Tone Affects Wearable Accuracy—and How Tech Giants Are Responding
Wearables now sit on well over a hundred million American wrists, yet their heart-rate readings do not perform equally on everyone. A 2025 review of accuracy studies found one major smartwatch brand held within 5 beats per minute across the full range of skin tones, while other devices under-read by 10 to 15 beats per minute on darker skin during moderate to vigorous exercise. Big discrepancies also showed up during cycling and resistance training. That matters beyond training zones, because heart-rate data can flag an irregular heartbeat, and the report goes on to describe how the major manufacturers are responding to the problem.
For you: If you have darker skin and lean on your watch's mid-workout numbers, worth knowing that accuracy varies a lot by device, so the model on your wrist matters as much as the metric.
What it shows: Reported by Outside and not verified by us: we could not trace this story to a published paper, so treat it as news rather than evidence we have checked.