New Study For Fitbit Lawsuit May Prove The Watches Are Inaccurate

Earlier this year a class-action lawsuit was filed against Fitbit, which argued that the PurePulse technology used in the Surge, Blaze, and Charge HR to measure heart rate, don’t actually work as accurately as they should. According to CNN, Fitbit denied the claim, but a recent study that was funded by the lawyers who filed the suit may prove the Fitbit trackers are actually inaccurate.

The lawsuit claims that if there is a defect in the trackers it’s a safety hazard because some people rely on those heart rate readings for medical purposes and if they’re inaccurate they could put these people at medical risk. Those involved in the class-action suit, according to CNN, said there was no way for them to know if the devices were inaccurate and had they known they wouldn’t have purchased the trackers.

On Thursday, May 19, an amendment was made to the complaint that added a new study, which looked at how the Fitbit trackers worked for 43 healthy adults with an electrocardiogram (ECG) and against each other. Each participant wore two Fitbits during the test. The study discovered that, on average, the Fitbit devices were off by 20 beats per minute during moderate to high-intensity exercise. CNN reports the lawsuit states the “devices could not provide meaningful heart rate data” when someone is exercising.

Although Edward Jo, one of the study’s authors, stated that the Fitbit devices worked well while participants rested, most people use their Fitbits to track their habits while exercising, which is one of Fitbit’s main selling points.

The Fitbit devices were tested on 22 men and 21 women in the study, all of whom were observed in one visit. The research was done by Jo and Brett Dolezal, scientists at California State Polytechnic University, Pomona and each participant wore the trackers, a Zephyr Technology BioHarness, and a single-channel ECG sensor.

Fitbit told CNN they object to the study, stating “it lacks scientific rigor and is the product of flawed methodology.”

“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,” said a Fitbit representative in a statement. “Furthermore, there is no evidence the device used in the purported ‘study’ was tested for accuracy.”

“Fitbit’s research team rigorously researched and developed PurePulse technology for three years prior to introducing it to market and continues to conduct extensive internal studies to test the features of our products,” the rep continued. “Fitbit Charge HR is the number one selling fitness tracker on the market, and is embraced by millions of consumers around the globe.”

Back in January when the lawsuit was first filed, Consumer Reports did their own small study of the Fitbit Charge HR and the Fitbit Surge. Using a male and female volunteer, the Consumer Reports team put them on a treadmill and used the Polar H7, a chest-strap monitor, for reference. Both subjects used the Fitbit Charge HR and the Fitbit Surge, wearing one on the wrist and the other a few inches higher.

The subjects’ heart rates were then recorded at four different levels of intensity, and all tests were conducted twice. ConsumerReports then confirmed that both Fitbit devices were accurate and that the variance between the chest strap and the Fitbit trackers amounted to no more than three heartbeats per minute.

Even so, the ConsumerReports test only included two participants, compared to the 43 subjects used in the more recent study, bringing into question the accuracy of the ConsumerReports’ research.

Fitbit continues to back their products however, the representative adding, “We stand behind our heart-rate monitoring technology and all our products, and continue to believe the plaintiffs’ allegations do not have any merit.”

As a multi-million dollar company, Fitbit has a lot to lose in this court case, and no doubt everyone will be interested to see how this all plays out.

[Photo by Eric Thayer/Getty Images]