Fitbit is facing a class-action lawsuit related to the accuracy of heart-rate tracking in its wearable devices, and a new study doesn't help its case. Researchers used Fitbit devices to track the heart rates of 43 adults during different physical activities. At the same time, they used an electrocardiogram to measure heart rhythm. They found that Fitbit readings were inaccurate by up to 20 beats per minute.
However, in a statement to Gizmodo, Fitbit said that the study was paid for by plaintiffs' lawyers and that the electrocardiogram used was not a clinical-grade device. "Consumer Reports independently tested the heart rate accuracy of the Charge HR and Surge after the initial lawsuit was filed in January and gave both products an 'excellent' rating," Fitbit said. RP