An engineer at a plotting instrument firm has done a close comparison of the heart rate monitoring in the Apple Watch to that of a highly accurate dedicated heart monitor, the Mio 2, which gives EKG-quality results from a wrist-worn device.
The engineer, SonoPlot cofounder Brad Larson, used the two devices to measure his own heartbeat at the same time, then plotted the results on a graph.
Here’s the graph: [see above]
As you can see, the Watch results track closely with the Mio 2’s. If we believe in the accuracy of the Mio 2 (and it’s proven out in scientific studies), the results suggest that the Apple Watch’s results are also highly accurate. That the two devices recorded the same results seems to validate the results themselves.
[Thanks Srikar Dhanakoti]