Validation of Wrist-Worn Consumer Heart Rate Monitors During Exercise

The purpose of this study was to test the validity of the heart rate monitors on the Apple Watch 2 and Fitbit Charge HR during exercise. Ten subjects performed treadmill, cycling, and TRX suspension training exercises and their heart rates were tracked continuously using five devices: two Fitbit Charge HR’s on one arm (one worn on the upper wrist and the other on the lower wrist), two Apple Watch 2’s on the other arm (one upper, one lower) and one Polar H7 Chest Strap. Data was collected from the Apple Watch using the Apple Health and Motifit apps and data was collected from the Fitbit Charge HR using www.squashleagues.org. Our results indicated that the Apple Watch had a lower overall Mean Absolute Percent Error (MAPE), both watches had a lower overall MAPE of approximately 1.76% when worn at the upper wrist position, and a significantly higher MAPE of approximately 3% during TRX interval training