If you've been wondering how accurate the Apple Watch's heart rate monitor is, we now have a better look at how exactly it performs against dedicated devices. Engineer Brad Larson measured the Apple Watch agains the Mio Alpha, and found they reported similar results after a run:

Larson posted a chart to go along with his findings:

Brad Larson's heart rate results

It looks like that secret health and fitness lab has paid off.

The Apple Watch heart rate monitor uses light to measure blood flow under your skin. While these new results point to the Apple Watch taking accurate readings, if you still feel that you need some external help, be sure to follow our guide to pairing an external heart rate monitor with your watch.

Source: Brad Larson (1), (2) (Twitter), via iClarified

Apple Watch