A new study about Fitbit's inaccuracy will surely raise a lot of pulses. Findings showed that the smartwatch brand's PurePulse technology is incapable of correctly monitoring heart rates.
In particular, the new study from the California State Polytechnic University found a 20-beats-per-minute (bpm) average difference between Fitbit devices and a conventional electrocardiogram when monitoring the heart rates during moderate to high-intensity exercise routines.
The study enrolled 43 healthy participants and tested two Fitbit products: Fitbit Surge or "Surge" and Fitbit Charge HR or "Charge HR."
The participants completed exercise routines that included running, climbing stairs and skipping, all of which were featured in the smartwatch's advertising campaigns.
"We conclude that the Fitbit PurePulse Trackers do not provide a valid measure of the users' heart rate and cannot be used to provide a meaningful estimate of a user's heart rate," says researchers Edward Jo, Ph.D. and Brett A. Dolezal, Ph.D. in the study document (PDF) released online by the plaintiffs' law firm Lieff Cabraser.
The study was part of an ongoing class-action lawsuit filed against Fitbit as commissioned by the lawyers who represent the group of customers.
Fitbit attacked the study results by challenging not just the quality of the electrocardiogram utilized, but also the study's method and purpose.
"What the plaintiffs' attorneys call a 'study' is biased, baseless, and nothing more than an attempt to extract a payout from Fitbit. It lacks scientific rigor and is the product of flawed methodology," said Fitbit.
However, this isn't the first time that Fitbit products missed a few heartbeats. In an earlier study conducted by a joint team of researchers and journalists from Indiana's Ball State University and WTHR, an NBC-affiliated TV station, the findings also showed that Fitbit Charge HR and Fitbit Zip were unable to properly monitor and count the correct number of steps the participants took.
There's more. In 2014, an article published in the Berkeley Science Review revealed that Fitbit's risk of error goes up along with your exercise intensity level.
This suggested that the products might not be "fit" for people who want to monitor their progress during intense exercise routines.