Smartwatches Overcount Exercise Calories by Up to 25%, With Apple Missing by About 15%
Updated
Updated · science20.com · Sep 5
Smartwatches Overcount Exercise Calories by Up to 25%, With Apple Missing by About 15%
1 articles · Updated · science20.com · Sep 5
Summary
A lab comparison of four consumer smartwatches found they overstated exercise calories by as much as 25% during controlled cycling workouts by 58 adults.
The test matched Garmin Forerunner 955, Fitbit Sense 2, Apple Watch Series 8 and Samsung Galaxy Watch against a COSMED K5 metabolic analyzer, pointing to software and algorithm flaws rather than sensor limits.
Apple was the least inaccurate at roughly 15% off, while Garmin and Samsung were the worst performers; Fitbit also produced erratic readings, including implausibly low totals and missing data.
Researchers said accuracy worsened for some body types, including people with higher body fat, and argued device makers rely too heavily on customer data instead of independent validation.
If your smartwatch overestimates calorie burn by 25 percent, could your favorite fitness tracker actually be secretly sabotaging your weight loss goals?
With algorithms failing users with higher body fat, are these expensive fitness wearables inherently biased against the people who need them most?