​Fitbit PurePulse heart rate accuracy questioned in lawsuit

In-house developed bpm tech at the centre of legal action Stateside
​Fitbit heart rate accuracy questioned

Back in January, Fitbit was hit with a class action lawsuit regarding the accuracy of its heart rate tracking.

A group of plaintiffs claimed that Fitbit's in-house PurePulse heart rate tech is "significantly" inaccurate and are seeking damages for "economic injury."

Those claims have now been boosted, with the attorneys who filed the lawsuit producing a study that claims to show Fitbit's heart rate accuracy is, on average, 20 beats per minute off during moderate to high-intensity exercise.

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The study was based on 43 healthy adults and the lawyers argue that it proves that the Surge, Blaze and Charge HR trackers "could not provide meaningful heart rate data".

Speaking to CNN, attorney Jonathan Selbin said: "This is about the way they market it and that they charge a premium for the heart rate monitor, but it's not giving a meaningful measurement."

The authors of the report state that Fitbit trackers work "pretty well" for resting wearers but the advertised "counting every beat" during exercise is false.

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The San Francisco based company has responded to the study, saying: "It was paid for by plaintiffs' lawyers who are suing Fitbit, and was conducted with a consumer-grade electrocardiogram, not a true clinical device, as implied by the plaintiffs' lawyers. Furthermore, there is no evidence the device used in the purported 'study' was tested for accuracy."

Back in January, when the claim was originally filed, it said: "It's also important to note that Fitbit trackers are designed to provide meaningful data to our users to help them reach their health and fitness goals, and are not intended to be scientific or medical devices," it said.

The second part of this statement has long been used as a defence by Fitbit when faced with criticism over accuracy of its heart rate technology. In our review of the Fitbit Charge HR, we detailed inaccuracies while exercising and at rest.

It's not the first time Fitbit has faced legal issues over the accuracy of its tracking, and it was slapped with a lawsuit back in May 2015 concerning its sleep monitoring stats.



  • M_Platenkamp says:

    I’m pretty much convinced now that Fitbit does not work! I am a heart patient from birth. Not a big deal but it's good to keep an eye on this which is why my wife bought me a Fitbit. I know for a fact that my heart rate is around 40bpm but my Fitbit insists that my heart rate is constantly around 90bpm, a few seconds later it’s 109bpm and a few second later it’s 80bpm. Btw, this is all when I’m sitting down and not moving… I'm pretty surethis thing is a hoax. Hopefully there’s a service number I can call for a proper explanation?

  • Kit says:

    I have had a SURGE for over a year. It has been flawless. I am a physician (MD, FAAFS Fellow American Academy of Forensic Sciences) and also have a PhD in Human Physiology. If the heartbeat  monitor is worn properly, and adjusted as described in the written material, it is exceptionally accurate. I test it daily on 4-mile runs, and review the data in detail. [I do not work for FitBit, nor have I ever received any compensation from them or other considerations.] The defense as describved by the FitBit Attorney seems very reasonable to me. 

  • Zerbear101 says:

    Seriously? Wow. Sorry, but if someone wants completely accurate information on their heart rate, get a medical device!

    My dad and I have been using Fitbits for a long time. Myself, to keep fit and stay motivated. My dad, to lose weight and stay motivated. He has lost 45 pounds! He is no longer obese. We challenge each other and stay active; which is the purpose on the Fitbit. The heart rate part of it is just fun to watch. Yes, I like to see, after my runs what my cardio and peak times are, but seriously, it is just an idea and if not totally accurate I wouldn't sue! Seriously?

    This is a frivolous lawsuit. Commentary on today's world.

    If you want 100% accuracy on your heartbeat, see a doctor and get an actual MEDICAL DEVICE!

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