Health & Fitness Bulletins

September 06, 2025

Accuracy of Wrist-Worn Heart Monitors

Wrist-worn smart watches and fitness monitors have become widely adopted by consumers and are gaining increased attention from researchers. 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.

Marc Gillinov, MD, chairman of the Department of Thoracic and Cardiovascular Surgery at the Cleveland Clinic, has studied the accuracy of the devices. His results are published in the Journal of the American Medical Association. His recent study includes the Fitbit Charge HR (Fitbit), the Apple Watch (Apple), the Mio Alpha (Mio Global), and the Basis Peak (Basis). Overall, the devices do not appear to be as accurate as chest-worn heart monitors. 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.