New Fitbit lawsuit claims its heart rate monitoring is inaccurate

A class-action lawsuit has been filed against Fitbit alleging that the heart rate tracking in its two products are alarmingly inaccurate.

Fitbit, the maker of the world's most popular fitness trackers, has been accused of selling devices that misreport their wearer's heart rate, potentially putting people's health at risk.

Yet Fitbit touted the technology with advertising slogans such as "Every Beat Counts" and "Know Your Heart", the suit contends.

Consumers in the USA allege the Fitbit Charge HR does not record heart rates accurately.

The lawsuit claims testing has confirmed that the San Francisco-based company's PurePulse Trackers "consistently mis-record heart rates by a very significant margin, particularly during exercise".

The lawsuit says Fitbit's PurePulse technology is to blame.

Due to the underestimated readings of the Fitbit Charge HR and Surge models, which retail for $150 and $250 respectively, the plaintiffs are asking the company to agree on a monetary settlement.

The Charge HR wristband and Surge fitness-centric watch both have what is called the "PurePulse" sensor on the underside of the tracker. It has also said that though trackers provide better heart rate data than measures such as gym equipment, they are not meant to be scientific. In some cases the plaintiffs claimed the trackers displayed their heart rates as almost half of their actual heart rates.

Lieff Cabraser partner Jonathan D. Selbin, who also represents plaintiffs, added that Fitbit tried to shield itself from being held accountable to consumers through use of a hidden arbitration clause and class action ban. But Fitbit's stock fell 18 percent that day with investors worrying that the strategy won't succeed against companies like Apple.

The problem with an inaccurate heart rate calculation is that the user's health is put in jeopardy. Fitbit's statement ends with a vital addendum: Its trackers are intended for fitness and shouldn't be expected to the take the place of a medical device. "Our team has performed and continues to perform internal studies to validate our products' performance", Fitbit's statement said. Urban has a family history of heart disease and bought the device to ensure his heart rate did not exceed his doctor's recommendation of 160 bpm.

Heather Pierce, a spokeswoman for the company, said that the case has no merit.

• $800M Powerball jackpot has Siouxlanders racing for tickets

• Police investigate mass pepper-spraying

• Shocking incident in Russian hospital: Doctor kills patient