Lieff Cabraser Civil Justice Blog
Independent Study Confirms Inaccuracy of Fitbit Heart Monitors

Independent Study Confirms Inaccuracy of Fitbit Heart Monitors

Is your fitness tracker really giving you accurate data – or just telling you what you want to hear? An independent news station WTHR in Indiana decided to test for itself. And the results confirm allegations from the recent Fitbit heart rate monitor fraud lawsuit. As WTHR puts it, “While the devices are sometimes on target, our test results show all of the activity trackers reported questionable calculations that are vastly inaccurate and, in some cases, even potentially dangerous to your health.”

WTHR’s testing included popular brands like Fitbit, Jawbone, and Garmin, as well as some lesser-known devices from the booming multi-billion dollar personal health monitor industry. Scrupulous in its methodology, the station notes “[we] bought all of the fitness trackers new and, yes, we read pages and pages of small print to make sure we followed all of the manufacturer instructions.” Though they note that they “let actual experts handle the testing” in a Ball State University lab headed by Dr. Alex Montoye. With references to the devices, Montoye noted, “They’re popular because the information they provide, it’s easily accessible data about yourself. As far as accuracy, I think people tend to put a lot more stock in the accuracy of these than maybe they should. I think they probably would be surprised.”

Montoye’s team discovered marked shortcomings in the devices when it came to two areas: activity calorie measurement, and more ominously, heart rate measurements.

Most of the activity monitors tested for WTHR grossly over-reported the number of calories actually burned. On average, even the best fitness tracker tested for WTHR was off by nearly 30% on calories burned, while three of the devices had an average error rate of 44% or more.

But when it came to heart rate measurement, Montoye’s team found rampant inaccuracies in the Fitbit Charge HR and an unrelated model they concluded were “bordering on dangerous.” As WTHR put it, “The box for the Fitbit Charge HR says ‘every beat counts.’ Despite what the package says, the tracking device inside missed lots of them.” For example, when the Fitbit detected one subject’s heart rate at 68 beats per minute, a state-of-the-art portable pulse oximeter showed her real heart rate was actually much higher at 91. And 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.

“That’s too high to be acceptable to us,” Montoye said. “Heart rate is a measure of exercise intensity. Small changes in intensity can affect the benefit you’ll receive, but they also increase your risk associated with the activity. That risk can be very real … so the heart rate has to be accurate.”

The bottom line, as Lieff Cabraser’s recent Fitbit heart rate monitoring fraud lawsuit alleges, is that basic inaccuracies in Fitbit’s heart rate monitors render the devices potentially dangerous, especially for people at high risk of heart disease.

Consumer Protection Attorneys at Lieff Cabraser

If you purchased a Fitbit Heart Rate Monitor (Fitbit Charge HR or Surge), you are welcome 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 answer any questions you may have about your legal rights.

About Lieff Cabraser

Recognized as “one of the nation’s premier plaintiffs’ firms” by The American Lawyer, Lieff Cabraser Heimann & Bernstein, LLP, has successfully litigated and settled hundreds of class action lawsuits in federal and state courts, including dozens of cases requiring manufacturers to remedy a defect, extend warranties, and refund to purchasers the cost of repairing the defective product. It has recovered billions of dollars for consumers in such cases. With sixty-plus attorneys in offices in San Francisco, New York, and Nashville, we are among the largest law firms in the United States that represent only plaintiffs.