|Overall, the chest strap was almost as good as the EKG, measuring 99% accuracy, which isnít too surprising as both technologies work the same way, capturing electrical activity directly from the heart.
Things dropped off for the commercial fitness bands, but it was the Apple Watch that maintained the most accuracy, managing around 91%, beating the Mio Fuse by a nose. The Fitbit Charge HR and Basis Peak had around 84% and 83% accuracy, respectively.
The reduced accuracy of wrist-based tracking isnít surprising to study co-author Dr Gordon Blackburn, director of cardiac rehabilitation at the Cleveland Clinic. ďYou need to have good contact between the photosensing cells; as a person is exercising more vigorously, thereís more bounce, so you may lose some of that contact,Ē he explained.