Today, there are a handful of gadgets which are capable of measuring heart-rate. As per director of cardiac rehab at the Cleveland Clinic, Dr. Gordon Blackburn, the measurements vary widely between devices to devices.
The heart beat accuracy study is conducted between renowned competitors like Apple Watch, Mio Alpha, Basis Peak and Fitbit Charge HR against the gold standard of an electrocardiogram machine. The heartbeat of 50 volunteers was calculated in different platforms during rest, during walking and during running.
The test result showed Apple Watch is able to deliver 90% accurate heart rate measurement whereas its competitors scored around 80% accuracy rate. The at rest heart beat estimation was more or less same of all the competitors. Apple left its competitors far behind in the estimation of heartbeat during physical activity.
Apple has a fine heart-rate calculator supported by two light guides along with software to measure vasculature changes.