A new study claims that mass-market wearable devices such as the Apple Watch may not be the best option for users tracking their body’s energy burnout rate after workouts. There is no dearth of medical analyses out there that have highlighted the inaccuracies of wearable devices for something as simple as step tracking to biomarkers as critically important as heart rate. But more than just generic accuracy, factors such as skin color are also known to affect PPG waveform while measuring heart activity.

A few months ago, research conducted by the experts at Florida International University’s Department of Biomedical Engineering observed that wearable devices from Apple and Fitbit are known to fail when capturing biomarker measurements for people with obesity or those with a darker skin tone, thanks in no part to signal loss. And as one climbs down the price ladder of wearables, the accuracy of onboard sensors also takes a huge hit.


Related: Google Wants You To Use Skin Gestures For Wearables, How Could It Work?

A study published in the European Journal of Sport Science compared energy tracking levels of the Apple Watch Series 6, the Fitbit Sense, and the first-generation Polar Vantage V. Readings were taken by medical-grade devices and the test pool of wearable devices, and were compared for reliability analysis alongside standardized typical error for each device. A score of ≥ 0.995 was graded as excellent, while a deviation <0.45 was ranked as impractical. In the tests, the Apple Watch Series 6 was graded impractical based on the standard error estimate, and based on the coefficient of variation, it was awarded the label of poor accuracy.

Not The First Failure For Wearables

In order to conduct tests on the aforementioned wearable devices, the team set a parameter for rating them based on percentage accuracy when compared to medical-grade devices, and the variations in results. The Apple Watch Series 6’s bad record also continued when it came to measuring energy expenditure for walking, running, resistance exercise, and cycling — all of which earned it the ‘poor accuracy’ label. The Fitbit Sense and Polar Vantage V also displayed poor accuracy for measuring energy expenditure.

However, it must be noted that the test circle was relatively small, as it involved a team of 30 men and an equal number of female participants aged between 22 years and 27 years, while their BMI was measured at the 23.1 mark on an average. Needless to say, that’s a very specific demographic to pass a verdict on the accuracy of the Apple Watch Series 6, given that the smartwatch is worn by millions of people all across the globe. The news wasn’t all bad for the Apple Watch though – the study determined the smartwatch delivers accurate heart rate tracking across various activities, unlike Fitbit and Polar which had fluctuating results.