We're constantly hearing different theories on fitness trackers, but researchers at Cleveland Clinic wanted to finally put an end to the discussion and determine the most accurate wrist-worn trackers that also monitor heart rate. In the study to end all studies, the Apple Watch came in first place with 90 percent accuracy, but here's how it all went down.
The study, which was recently published in JAMA Cardiology, tested how popular wearable devices measured heart rate by looking at the calories burned during exercise. Researchers monitored 50 healthy adults, who were all hooked up to an electrocardiogram (EKG) machine and then compared the EKG results to the Fitbit Charge HR, Apple Watch, Mio Alpha, and Basis Peak fitness trackers in addition to a chest strap. The EKG is accepted as being the most accurate way to measure an individual's heart activity. Researchers measured the participants at rest, walking, and jogging on a treadmill to calculate the activity.
The chest strap had a 99 percent accuracy rate. Considering the chest strap's close proximity to the heart, the incredibly accurate results should come as no surprise. When looking at the wearables, the Apple Watch had an overwhelming 90 percent accuracy rate, but "the other ones dropped off into the low 80s for their accuracy," Dr. Gordon Blackburn, one of the study's authors, told Time. He pointed out that measuring heart rate through wrist technologies isn't always the most accurate because they look at blood flow to determine heart rate and with more intense exercise "there's more bounce, so you may lose some of that contact."
"What we really noticed was all of the devices did not a bad job at rest for being accurate for their heart rate, but as the activity intensity went up, we saw more and more variability," Dr. Blackburn said. "At the higher levels of activity, some of the wrist technology was not accurate at all."