Fitness tracking kingpin Fitbit is the subject of a class-action lawsuit over allegations its heart-rate tracking technology is inaccurate.
The data is particularly off during heavy exercise, according to the claimants from California, Colorado and Wisconsin.
The complainants are seeking compensation, plus damages for so called “economic injuries.”
Fitbit has promised to “vigorously defend” the lawsuit, claiming its devices aren’t intended for use as scientific and medical devices.
The company said: “[We] strongly disagrees with the statements made in the complaint and plans to vigorously defend the lawsuit…PurePulse [Fitbit’s proprietary heart rate tech] provides better overall heart rate tracking than cardio machines at the gym, as it tracks your heart rate continuously even while you’re not at the gym or working out.
The class-action suit arrived during a rough week for the market leader.
The unveiling of the new Fitbit Blaze smartwatch at CES 2016 caused shares to drop 18 per cent.
Fitbit’s first official smartwatch is an affordable alternative to the Apple Watch and Android Wear devices will be out in March.
It offers a simpler approach than many of the leading smartwatches, building upon the firm’s fitnesses-focus offerings.
Fitbit CEO James Park says: “People have struggled with what the killer app is for smartwatches. For us it’s health and fitness. It’s really cumbersome on the Apple Watch sometimes to see what is my daily activity because they are trying to do so many things.”
Apparently, shareholders failed to agree. After a great 2015, this year hasn’t gotten off to the best start for Fitbit.