Fitbit, the wearable fitness tracker, has gone from strength to strength since its launch. The company recorded a record $1.858 billion (!) in revenue at the close of the 2015 financial year, and, due to its affordable price tag, everyone from we regular folk, to soon-to-be ex-P.O.T.U.S. Barak Obama can be seen wearing one. That said, Fitbit are known to court controversy; in 2015, it was suggested that the advertised “sleep-tracker” in the company’s Flex model was inaccurate, and over-logged sleep. This case is still ongoing, but it is important to note that it is not suggesting negligence with regards to health; rather that the product itself was falsely advertised. It remains to be seen how this case will play out, but as if that wasn’t enough, at the beginning of the year, a multiple-plaintiff class action lawsuit was filed, with a study showing evidence that Fitbit’s PurePulse technology was woefully inaccurate during exertion.
The study, performed by a team at California State Polytechnic, compared exertional heart rates acquired via the wearable device and from an ECG. After exercising 43 individuals for 65 minutes, it was noted that the various Fitbit models displayed a heart rate that differed by up to 22bpm compared to that on the ECG, and that some didn’t display a heart rate at all.
According to the study’s team, there exists a distinct lack of rigorous, scientific testing in the wearables market (this is further suggested by lawsuits filed against other, similar product developers), but Fitbit have dismissed both this statement and the study itself, citing bias and, perhaps humorously for reasons I shall soon disclose, a lack of scientific methodology. Fitbit have stated that they perform extensive testing during development, and have pointed towards another study which purports to have found PurePulse products to be highly accurate, although it is important to note that this particular study tested a sample size of two (yes… two).
Wearable devices aren’t anything new, but with technological advances, they are no longer being seen as simply fitness trackers and companies are exploring their application in healthcare. As this gains further traction, accuracy will be incredibly important. In fact, one of the plaintiffs in this case, an 82 year old woman, has alleged that her device underestimated her heart rate by such a margin, that were she to have tried to reach her supposed target heart rate, she would have likely done serious damage to her health, so it is already having a potential impact.
The company’s financial growth since the launch of this generation of devices is thought to be largely due to PurePulse, what with it being the most heavily marketed new feature, so Fitbit’s request that the case be dismissed has last week been denied. Judge Susan Illston has decided that the plaintiffs case has sufficient merit, with regard to fraudulent claims about Fitbit’s accuracy, so it will be considered in court. This does not necessarily give an indication as to the outcome, however.
The Student Physiologist 