Fitbit: Study Says Your Favorite Fitness Tracker Bites

Fitbit's Chief Revenue Officer Woody Scal and Indian Bollywood actors Shraddha Kapoor (L) and Tiger Shroff

Fitbit’s Chief Revenue Officer Woody Scal and Indian Bollywood actors Shraddha Kapoor (L) and Tiger Shroff | Saijad Hussain/AFP/Getty Images

One of the most useful and exciting fitness products to hit the market over the past decade are fitness trackers. Though they’re now made by numerous companies and manufacturers, many people will always have a special place in their hearts — and on their wrists — for Fitbit. With “fit” right in its name, Fitbit became more or less the gold standard for fitness trackers, even when competitors flooded the market with alternatives.

These days, there are a number of Fitbit models and variants to choose from (including the new Fitbit Charge), each able to keep you on track when it comes to getting enough exercise during the day. Or so you thought.

A new study has called the reliability and accuracy of Fitbit into question and has many people wondering if they’ve been getting nothing but bad information from their wrist rider. This doesn’t bode well for the company, especially considering that it’s already facing a class action lawsuit from users who have had issues with the devices.

Researchers at California State Polytechnic University, Pomona conducted the study on behalf of the law firm Lieff Cabraser Heimann & Bernstein, which filed the lawsuit back in January. The study says that Fitbit devices produce heart rate monitor readings that are “highly inaccurate”, and that they “cannot be used to provide a meaningful estimate of a user’s heart rate.”

“This study was designed and executed to test the accuracy of the heart rate monitoring technology—PurePulse—in fitness trackers manufactured by Fitbit, Inc.” study authors Edward Jo, PhD and Brett A. Dolezal, PhD said of their tests, which used the Fitbit Charge HR and Surge models. “Based on our analysis of those readings, we conclude that the Fitbit PurePulse Trackers do not provide a valid measure of the users’ heart rate,” they write, “particularly during moderate to high-intensity exercise.”

In other words, the study found that Fitbit’s devices fail at the one thing they’re actually supposed to do.

As for how far off the Fitbit devices actually were in their monitoring, the study says that in some cases, it could be as much as 20 beats per minute — which, for those familiar, is a fairly significant amount. It could mean that Fitbit users have been getting significantly less exercise than they previously thought, or have thrown off their workouts in any number of ways.

The researchers reached their conclusions by “comparing hundreds of thousands of  heart rate readings to a time-synced electrocardiogram (“ECG”),” and provided a number of visual aids and charts throughout their 24-page report.

Fitbit fires back

“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. 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,” a Fitbit spokesperson told The Cheat Sheet, in an emailed statement.

“Fitbit’s research team rigorously researched and developed the technology for three years prior to introducing it to market and continues to conduct extensive internal studies to test the features of our products. Fitbit Charge HR is the #1 selling fitness tracker on the market, and is embraced by millions of consumers around the globe.”

Clearly, things are getting messy.

A few Fitbit models are displayed

A few Fitibit models are displayed | Fitbit

Are fitness trackers inaccurate?

For fitness tracker owners or those who are looking to pick up a fitness tracker in the near future, the question at the center of all this is whether the study’s claims are accurate. It’s unclear at this point, but the findings do seem consistent with many others out there, and there are a slew of complaints about fitness trackers of all makes and models regarding inaccuracies.

As The Cheat Sheet has written about previously, many fitness trackers simply don’t work very well — for a host of reasons. Many companies are shipping them before they’re ready or able to function at full capacity, with the goal of getting the product to market and making adjustments along the way. There have also been issues involving trackers made from materials that cause reactions when in contact with users’ skin and sweat.

On top of all that, other studies and cases have shown that using fitness trackers can actually be detrimental to our workouts by making them less enjoyable. This, of course, doesn’t speak to the inaccuracy claims but is something to take into account when shopping for a tracker, Fitbit or otherwise.

So, when it comes down to it, there does appear to be something amiss with Fitbit’s technology — at least enough to warrant a class action lawsuit and some resources diverted into an additional study. There’s still nothing definitive yet, though this most recent study does, once again, seem to bolster previous complaints.

Fitbit is still adored by millions, but if you’re looking to pick one up, just be aware that the accuracy of its devices is in question.

Follow Sam on Facebook and Twitter @Sliceofginger

More from Health & Fitness Cheat Sheet: