Accuracy of Wrist-Worn Heart Monitors

While accuracy of chest strap, electrode-based heart-rate monitors has been confirmed, research shows that wrist-worn fitness trackers may not be the best way to measure heart rate.

While some wrist-worn monitors are more accurate than others, studies show they are not as accurate as chest-worn heart monitors. Marc Gillinov, MD, chairman of the Department of Thoracic and Cardiovascular Surgery at the Cleveland Clinic, has studied the accuracy of the devices.

Dr. Gillinov and colleges recruited 50 healthy adults and randomly assigned each of them to wear two of four wrist-worn fitness devices with heart monitors, one on each wrist. Fitness trackers included the Fitbit Charge HR (Fitbit), the Apple Watch (Apple), the Mio Alpha (Mio Global), and the Basis Peak (Basis). The participants wore the devices while walking or running on a treadmill. All the participants also wore standard EKG electrodes and a chest-worn monitor.

Heart rate was measured with participants resting, walking, or running on a treadmill at various settings. The participants exercised for three minutes at each setting and recorded their heart rates at the three-minute point. Recovery rate was also measured at 30, 60, and 90 seconds at the end of the three minutes.

Researchers found that the wrist monitors demonstrated variable accuracy, with median differences hovering around 8 beats per minute during exercise. The wrist-worn devices were most accurate at rest, and that accuracy diminished with exercise.

Dr. Gillinov says wrist-worn monitors are fine for recreational use, but probably won’t be replacing EKGs in the medical setting any time soon. While wrist devices may have not reached the accuracy of chest devices, both can provide valuable input for gauging exercise programs.

Source:

Wang R, Blackburn G, Desai M, Phelan D, Gillinov L, Houghtaling P, Gillinov M. Accuracy of wrist-worn heart rate monitors. JAMA Cardiology. 2017 Jan 1;2(1):104-6.