New Study Tears Into The Accuracy Of Fitbit Heart Rate Trackers

In January of this year, a lawsuit seeking class action status was filed against Fitbit alleging the the company’s line of heart rate trackers were woefully inaccurate, with a new study released today that lawsuit may have just gained some traction.

Fitbit lawsuit gets stronger?

Back in January, three people filed a lawsuit against Fitbit with their lawyers making it quite clear that they would like to extend the suit’s scope.

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Speaking on the Today Show, one of the plaintiffs, Kate McLellan, said, “I’m a mom. I like to work out. I like to be fit. My Fitbit was saying that [my heart rate] was at 114, which is really, really low.”

Not believing her tracker to be accurate she contacted customer service and quite simply angered with the company’s answers.

“She made it sound like it was my fault, like I was using it wrong or wearing it wrong,” McLellan said of her discussion with customer service. “She said it’s not really meant to track your heart rate all of the time.”

“We do not believe this case has merit,” a spokesperson for Fitbit said in a statement when the suit was filed. “Fitbit stands behind out heart-rate technology and strongly disagrees with the statements made in the complaint and plans to vigorously defend the lawsuit.”

New study backs up lawsuit claim?

A study by researchers at California State Polytechnic University, Pomona has them seemingly agreeing with McLelland with the findings calling Fitbit’s PurePulse heart rate monitors “highly inaccurate.”

The study involved 43 people who were asked to put a Fitbit Surge watch and Charge HR band on each wrist. At the same time, the researchers hooked up each of the participants to a BioHarness in order to provide them with an electrocardiogram (ECG) which is known to be highly accurate.

The participants than went about a series of exercises including the use of treadmills, jogging outside, jumping rope and others and the researchers found that during intensive workouts, Fitbit’s performace was way off with heart rates being off by as many as 20 beats per minute as intensity increased.

“The PurePulse Trackers do not accurately measure a user’s heart rate, particularly during moderate to high intensity exercise, and cannot be used to provide a meaningful estimate of a user’s heart rate,” the study stated.

Fitbit rails against the study

There surely appears to be a conflict of interest in the study as it was paid for by the law firm leading the class action suit, Lieff Cabraser.

Fitbit issued a long statement to Gizmodo today blasting the study which the company believes was simply commissioned in order to elicit a payment from the company to settle the suit.

The scathing criticism of the study read:

“What the plaintiffs’ attorneys call a “study” is biased, baseless, and nothing more than an attempt to extract a payout from Fitbit. 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. Furthermore, there is no evidence the device used in the purported “study” was tested for accuracy.”

After speaking to the work Fitbit’s researchers did for years before releasing the aforementioned products, the company spoke to the independent testing that its products have gone through.

“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. We stand behind our heart-rate monitoring technology and all our products, and continue to believe the plaintiffs’ allegations do not have any merit. We are vigorously defending against these claims, and will resist any attempts by the plaintiffs’ lawyers to leverage a settlement with misleading tactics and false claims of scientific evidence.”

While that may be the case, this is not the first study that has showed Fitbit’s heart rate tracking inaccurate.

A study released in February by Ball State University in Indiana, found the Charge HR missed heartbeats.

“Calculating a heart rate that’s off by 20 or 30 beats per minute can be dangerous — especially for people at high risk of heart disease,” the February report stated.

Fitbit also refuted that study’s claims by saying that the Charge HRs “are designed to provide meaningful data to our users to help them reach their health and fitness goals, and are not intended to be scientific or medical devices.”