Smartwatches have been found to “significantly overestimate” how many calories people burn during exercise and estimates become even less accurate as body fat increases.
Researchers at Florida International University (FIU) tested four popular fitness trackers – the Apple Watch Series 8, Fitbit Sense 2, Samsung Galaxy Watch 5 and Garmin Forerunner 955 – against clinical-grade laboratory equipment that measured participants’ true energy use.
They found typical errors in smartwatch calorie estimates of about 15% to 25%, with averages for the worst-performing watches climbing much higher. Apple’s devices proved to be the most accurate, while Garmin and Samsung were prone to overestimating.
The discrepancy means if a smartwatch claims that 500 calories were burned during a workout, the real number could be closer to 350. This misrepresentation could be especially important for people who use fitness trackers and calorie-burn estimates for weight management.
“You can’t treat the calories burned...