FitBit makes heart tracking devices that are popular with exercise enthusiasts, but a new lawsuit claims that the devices aren’t even close to accurate. In fact, the words “wildly inaccurate” are used in the lawsuit itself, and that suit claims that the company, therefore, is guilty of false advertising.

The complaint was put into the court system in San Fransisco, in the federal courts. It says that the trackers are so wrong that they come close to being a health risk, rather than keeping people healthy, which is what they’re intended to do.

One woman from Colorado reported findings that back up these claims, if they’re true. She has a device called a “Charge HR,” and she says that the heart tracker reported that her heart was going as much as 50 percent slower than it actually was. She was doing intense exercise at the time.

This is problematic because those who do intense exercise often want to push their heart rates up to a certain level, where they get the most health benefits. A tracker that under-reports the rate could cause them to shoot for rates that they’d never consider otherwise.

The class action lawsuit notes that the complaints coming in from users aren’t isolated incidents.

To its credit, FitBit came to the defense of the heart trackers. According to the company, they have done internal studies to find out how accurate the trackers are, and they’ve not run into these issues.

When companies misrepresent products, customers may have a right to seek compensation; this is especially true if problems with the products lead to health issues.

Source: Bloomberg Business, “FitBit Sued Over Claims Heart Trackers Miss the Beat Big-Time,” Kartikay Mehrotra, Jan. 06, 2016