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Class Action Lawsuit Filed Against Fitbit For 'Highly Inaccurate' Heart Rate Trackers (nbcnews.com)
An anonymous reader quotes a report from NBC News: A class action lawsuit against Fitbit may have grown teeth following the release of a new study that claims the company's popular heart rate trackers are "highly inaccurate." Researchers at the California State Polytechnic University, Pomona tested the heart rates of 43 healthy adults with Fitbit's PurePulse heart rate monitors, using the company's Surge watches and Charge HR bands on each wrist. Subjects were then hooked up to a BioHarness device that produced an electrocardiogram (ECG), to record the heart's rhythm against the data being produced by Fitbit's devices. Comparative results from rest and exercise -- including jump rope, treadmills, outdoor jogging and stair climbing -- showed that the Fitbit devices miscalculated heart rates by up to 20 beats per minute on average during more intensive workouts. The study was commissioned by the Lieff Cabraser, the law firm behind the class action suit that is taking aim at three Fitbit models that use the PurePulse heart monitor, including the Fitbit Blaze, Fitbit Charge HR and Fitbit Surge. "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," Fitbit said in a statement posted by Gizmodo.
Once again I come here to defend my Fitbit Charge HR: I'm trying to lose weight, and it works great for keeping a gross measure of calorie burn vs intake. Its "imprecise" HRM is a lot better than a step counter at counting calories spent, even on average - even if the instantaneous heart rate is 10-20 BPM off from the actual one, you're likely still in the zone it uses to calculate calories. And it isn't off that long from my own experience. I have simultaneously used twice or "thrice" a Charge HR, Mi Band Pulse and chest HRM on workout sessions, and despite both imaging-based devices rarely being on the same as the chest one, they correct themselves to "close enough" status after seconds, and you don't change zones in seconds. The Fitbit is much better than the Mi Band as it clearly scans with a much higher frequency (I can see just from the leds lighting more often on exercise mode on both). At the end of the day, apps that use the chest monitor will basically provide the same calorie output as both the Charge and the Mi Band. I believe all this ruckus from over-expectationers is because they couldn't distinguish the type of product they were buying - people in the cities, more likely to purchase such devices are also more prone to use gyms and practice amateur sports, thus require better accuracy found in a chest HRM. But in part, this was also Fitbit's mistake: selling the product as such and targeting a market too focused on unimportant markers such as second-accurate BPMs.