A study published by researchers at California State Polytechnic University, Ponoma, that finds certain Fitbit trackers are not accurate when it comes to heart rate monitoring is being called biased by the fitness wearables company, Gizmodo reports.
The study, funded by Lieff Cabraser Heimann & Bernstein, a law firm that currently represents plaintiffs in a class-action lawsuit against Fitbit, determined technology used in Fitbit devices to be inaccurate, "particularly ... during moderate to high intensity exercise." The researchers noted that Fitbit devices inconsistently measure users' heart rates, saying that "it may be speculated that the current algorithms for heart rate estimation lack proper sophistication and sufficient data support to control for the multitude of confounding factors associated with PPG-based heart rate detection."
Fitbit fired back via a statement, according to Gizmodo, saying the study "lacks scientific rigor" and calling it "a product of flawed methodology."
Previous research also has called into question the accuracy of Fitbits and other wearable technology. For instance, a study published recently in the Journal of the American Medical Association found that most wearable devices do not produce accurate results for tracking energy expenditure; Fitbit was one of 12 wearables examined by the researchers.
Fitbits have been used by doctors in some cases to aid in making medical decisions about care. For instance, a case report published last month in the Annals of Emergency Medicine detailed how emergency medical staff at one hospital were able to use data from a patient's Fitbit Charge HR device to determine the timing of an arrhythmia episode in choosing a rhythm conversion treatment approach.
In addition, the Wall Street Journal, in 2014, detailed how Fitbits were used at the Mayo Clinic College of medicine to track activity of cardiac-surgery patients, who were discharged sooner if they recorded a higher level of post-surgical activity.