Fitbit Class Action: New Study Shows Fitness Tracker Not Accurate

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Last week, plaintiffs filed an amended class action lawsuit against Fitbit Inc., pointing to a new study that indicates the popular fitness tracker is not completely accurate.

According to the amended Fitbit class action lawsuit, Fitbit has touted its activity trackers as having the ability to accurately record a person’s heart rate during intense physical activity. Fitbit reportedly uses an LED-based technology called “PurePulse” to perform this function. The PurePulse technology is installed in Fitbit’s Charge HR, Surge and Blaze fitness watches. The Fitbit activity trackers at issue in the class action lawsuit reportedly retails at prices ranging from $150 to $250.

Fitbit claims that these LED lights can detect changes in capillary blood volume, and that it applies “finely tuned algorithms” to measure the heart rate and track workout intensity. Fitbit’s wearable technology is attractive to consumers because it is designed to be worn on the wrist as opposed to traditional heart rate monitoring technology which typically requires users to wear uncomfortable chest straps.

“Fitbit’s representations are repeated in and echoed throughout its advertising of the PurePulse Trackers—including for example, in commercials run repeatedly during Major League Baseball’s nationally-televised 2015 World Series—which employs such descriptive slogans as ‘Every Beat Counts’ and ‘Know Your Heart,’” the Fitbit class action lawsuit states.

“But those representations are false,” the fitness tracker class action lawsuit continues. “Far from ‘counting every beat,’ the PurePulse Trackers do not and cannot consistently and accurately record wearers’ heart rates during the intense physical activity for which Fitbit expressly markets them.”

According to the Fitbit class action lawsuit, the plaintiffs have all observed that their Fitbit fitness trackers under-recorded their heart rates during exercise. They compared the heart rate indicated on their Fitbit with results from an actual heart rate monitor, and found that the heart rate readings on their Fitbit trackers were “wildly inconsistent.”

The plaintiffs assert that many consumers have observed that the PurePulse trackers inaccurately record heart rates during exercise, and that a recent study funded by the plaintiffs’ lawyers confirms these observations. The Fitbit class action lawsuit points to research performed by professors at California State Polytechnic University, Pomona, who found that the Fitbit PurePulse Trackers are inaccurate by nearly 20 beats per minute during moderate to high-intensity exercise, and that these Fitbit activity trackers cannot provide meaningful heart rate data.

According to the Fitbit class action lawsuit, the Cal Poly professors tested the Fitbit trackers on 43 people who engaged in activities such as jogging, jump roping, plyometrics and stair climbing while wearing a Fitbit tracker on each wrist. The professors then compared the heart rate data provided by the Fitbit trackers and measured them against an electrocardiogram, described as “the gold standard of heart rate monitoring.”

The Cal Poly professors found that the data provided by the Fitbit activity trackers differed from the ECG results by an average of 19.2 beats per minute, without considering data from Fitbit trackers that recorded no heart rate at all. The researchers concluded that the PurePulse trackers cannot be used to provide a meaningful estimate of a Fitbit wearer’s heart rate.

The plaintiffs are represented by Elizabeth J. Cabraser, Kelly M. Dermody, Kevin R. Budner and Jonathan D. Selbin of Lieff Cabraser Heimann & Bernstein LLP, Adam C. McCall, Lori G. Feldman, Andrea Clisura and Courtne E. Maccarone of Levi & Korsinsky LLP and Robert Klonoff of Robert H. Klonoff LLC.

The Fitbit Fitness Tracker Class Action Lawsuits are Kate Mclellan v. Fitbit Inc., Case No. 16-cv-00036-JD and Judith Landers, et al. v. Fitbit Inc., Case No. 16-cv-00777-JD, in the U.S. District Court for the Northern District of California, San Francisco Division.

UPDATE: On Aug. 26, 2016, the plaintiffs argued that the court, not an arbitrator, should decide whether or not the class action claims should be subject to Fitbit’s arbitration clause. 

UPDATE 2: On Sept. 26, 2016, the plaintiffs in a Fitbit class action lawsuit are asking for a federal judge’s help in getting the defendant to respond to requests for discovery documents.

UPDATE 3: On Jan. 9, 2017, Fitbit urged a California federal judge to compel arbitration in a proposed class action lawsuit alleging the company’s popular wearable fitness trackers do not accurately record heart rates.

UPDATE 4: On June 5, 2018, a California federal judge has decided to allow the majority of claims in a class action lawsuit that alleges Fitbit devices cannot accurately read heart rates as advertised.