Lieff Cabraser Civil Justice Blog
Media Attention Focuses on New Fitbit Heart Rate Accuracy Study Confirming Significant Inaccuracies in Device Data

Widespread Media Attention Focuses on New Fitbit Heart Rate Accuracy Study Confirming Significant Inaccuracies in Device Data

Numerous news outlets such as CNBC, Forbes, CNN, Inquisitr, The Register, and Gizmodo have been reporting on the recent Fitbit heart rate accuracy study, which claims that several of the newest models of the popular fitness tracker devices are “highly inaccurate” when it comes to measuring active heart rates. The study discovered that the devices were off by an average of 20 beats per minute during moderate- to high-intensity exercise. 

Researchers at the California State Polytechnic University, Pomona tested the heart rates of 43 adults wearing Fitbit’s PurePulse heart rate monitors in the Surge and Charge HR bands for 65 minutes of physical activity. 22 men and 21 women were then hooked up to a Zephyr Technology BioHarness that produced an electrocardiogram (ECG) to record each user’s heart rate.

Based on the results of the study, researchers concluded that “[t]he 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,” as reported by Gizmodo.

“It works pretty well when you are resting,” stated study co-author Edward Jo. However, Fitbit is “advertised to people who exercise,” and the company’s marketing efforts suggest that the fitness trackers are “counting every beat,” according to CNN.

“The results from both devices showed a difference in heart rates to the ECG,” reported Wired UK. “The Surge was an average of 22.8 bpm off of the ECG, while the Charge HR recorded a difference of 15.5 bpm.”

“We are not arguing that it is a medical device. I think that is irrelevant,” explained Lieff Cabraser plaintiffs’ attorney Jonathan D. Selbin. “This is about the way they market it and that they charge a premium for the heart rate monitor, but it’s not giving a meaningful measurement.”

An amended complaint was filed last week in the consumer fraud class action case against Fitbit, Inc. over complaints that that various Fitbit heart rate monitors – now including three Fitbit models equipped with the PurePulse™ technology, the Fitbit Blaze™, Fitbit Charge HR™ and the Fitbit Surge™— fail to accurately measure user heart rates during exercise, the precise use for which Fitbit markets them.

“If they had just been honest, and said it can give you a ballpark figure most of the time, or if the marketing emphasized that you can use these when you are aspiring to be healthier, that would have been OK, but that’s not how they market it, and they charge a premium for it,” said Selbin.

Consumer Protection Attorneys at Lieff Cabraser

If you purchased a Fitbit Heart Rate Monitor (Fitbit Charge HR™, Blaze™, or Surge™), we invite you to visit our Fitbit Heart Rate Monitor lawsuit page to contact a consumer attorney at Lieff Cabraser. We welcome the opportunity to learn of your experiences with your Fitbit Heart Rate Monitor and to answer any questions you may have about your legal rights.