One of the complaints we often hear about the Apple Watch is that it is not as reliable as a dedicated device. In this case, the YouTube channel The Quantified Scientist compared the Apple Watch Series 7 heart rate sensor a few months ago with the Polar H10, a chest heart rate sensor. And the results are startling, as the Apple Watch tracks the chest sensor almost to the millimeter.

A very precise Apple Watch Series 7

This YouTube channel specializes in measuring the accuracy of different products. Between them and during a spinning session, he picked up the latest generation Apple Watch available and compared it to the most accurate commercial way to measure heart rate: a chest sensor. In its analysis of the Apple Watch Series 7, we can see the following graphs:

Here’s how the Apple Watch Series 7 compares to a Polar H10 when measuring heart rate. Each of these dots represents a reading from the Apple Watch while the diagonal is the chest sensor reference. As can be seen, the points are quite close to the diagonal.

And in this video from the same channel, we have Samsung’s Galaxy Watch 4 as a reference, where the dots are much more scattered on the graph. A tendency to accumulate on one side can also be observed.

The author also checked how the Apple Watch reacts during the hour-long spin test, with breaks of a few minutes. In pink we can see the reading of the Apple Watch and in turquoise that of the chest strap. The pink line is barely visible because it is “buried” under the Polar H10.

In the same test, the Samsung watch isn’t as accurate and doesn’t track the Polar H10’s readings by wake. In general, it seems to take a little longer than necessary to measure the onset of rest and the onset of exertion, with some irregularity in the quiet phase.

It is striking that a device for general use is more accurate than a Garmin, for specialized use in sports

Interestingly, in other comparisons with the Garmin Venu2 and the Xiaomi MiWatch, similar results are obtained to those of the Galaxy Watch. Scattered readings on the graph that indicate poor accuracy. Especially striking in a device like the Garmin, which is supposedly “designed” for sports.

Of course, tests like these are very necessary to know the accuracy of a product like the Apple Watch. It never hurts to know how it stacks up against dedicated devices and also the competition.