Wrist-based heart-rate monitoring may not be so handy

It might avoid the faff of a chest strap, but recent US research1 places a question mark over the accuracy of wrist-based heart-rate monitoring. Fifty subjects exercised while their heart rates were recorded using one of four wrist-worn monitors as well as a chest-strap monitor and an electrocardiogram (EKG). While the chest-monitor readings tallied with the EKG, wrist-based devices registered 15-34 beats per minute over or under. At rest, the readings were more reliable, but if heart rate is an important metric for you, a wrist monitor might not provide the accuracy you need.