A study recently published by the American Medical Association evaluates the accuracy of wrist heart rate monitoring devices.
With the rapidly growing popularity of heart-rate monitoring devices such as Fitbit & Apple Watch, until now, there hasn't been a proper scientific study to confirm the claimed accuracy of these devices.
While the accuracy of chest worn HR monitors using EKG-type technolohy, like the Mi Pulse Smart Sports Bra, has been conclusively proven, the accuracy of wrist-worn, optical HR monitors has never been vetted.
To evaluate the accuracy, this study assessed the accuracy of 4 popular wrist HR monitors (Apple Watch, Fitbit Charge HR, Mio Fuse, and Polar H7) under varying levels of physical exertion. 50 people wore each device while exercising at varying intensities on a treadmill. The subjects were also connected to medical-caliber EKG machines to simultaneously gather accurate heart rate data.
Results of the Study
This study absolutely confirmed wrist heart rate monitoring is inaccurate. Although some of the devices did better than others, the rate calculated by wrist monitoring devices was inaccurate up to nearly 20% of the time.
And, to top it off, the researches discovered something particularly alarming: the harder someone works out, the less accurate a wrist monitor becomes. This is because the optical technology used in wrist monitoring devices cannot compensate for the physical movement of your arms and wrists during exercise. As you exercise harder, your limbs move more, causing the device to move around, leading to inaccurate readings.
Why These Results Matter to Athletes
So why is this important? To an athlete focused on improving results, accurate heart rate measurement is a critical part of a training program. Many athletes try to keep their heart rates in an optimal zone to maximize efficiency and fat-burning activity. If relying solely on a wrist heart monitor, the now-demonstrated inaccuracy means a person may be working too hard, or not hard enough. At best, this could lead to poorer-than-anticipated results, or at worst, possibly injury.
For athletes who demand the best quality heart rate data, the only choice remains chest heart rate monitors, like the Mi Pulse Smart Sports Bra.