The Fitbit heart rate monitoring and fitness tracking wristbands are “highly inaccurate”, according to a new study.
The study was carried out by researchers from California State Polytechnic University who found that Fitbit’s PurePulse technology was “inaccurate” and “inconsistent”.
The researchers said that Fitbit wristbands do not accurately measure heart rates and are unable to provide meaningful estimates of beats per minute.
“The PurePulse technology embedded in the Fitbit optical sensors does not accurately record heart rate, and is particularly unreliable during moderate to high intensity exercise,” the study said.
The study was carried out after a lawsuit was launched against the makers of Fitbit after a user claimed the wristbands “do not and cannot consistently and accurately record wearers’ heart rates during the intense physical activity for which Fitbit expressly markets them”.
In order to review the claims, researchers tested two versions of Fitbit’s wristbands, the Surge and Charge HR, on 43 healthy adults.
The participants completed various activities including jumping rope and more intense running over a 65 minute period. The results found that the greater the level of activity, the more inaccurate the readings were from either device.
The researchers found that that not only were the readings inaccurate when tested against an ECG but that they also gave different and inaccurate readings when tested again the other on the same patient.
In response to the findings, Fitbit released a strongly worded statement saying the study was “biased, baseless, and nothing more than an attempt to extract a payout from Fitbit”.
Fitbit said the study: “lacks scientific rigour and is the product of flawed methodology” and that “it was paid for by plaintiffs’ lawyers who are suing Fitbit, and was conducted with a consumer-grade electrocardiogram – not a true clinical device, as implied by the plaintiffs’ lawyers.”
Fitbit also said that its PurePulse Technology took three years to develop and that the company carries out “extensive internal studies” in order to help test the accuracy of its products.