Those smartphone apps which say they track your step counts are remarkably accurate, scientists say.
After testing 10 of the step-counting technologies, US researchers found that the recorded step-data from smartphones is accurate.
The study, published in the medical journal JAMA, found only a slight variation in observed and actual steps.
However, wearable devices had a larger variation and one device reported step counts more than 20% lower than observed.
Mitesh S. Patel of the University of Pennsylvania and colleagues recruited healthy adults to test the accuracy of smartphone applications and wearable devices.
The apps and devices tested: the Digi-Walker SW-200 pedometer (Yamax); the Zip and One (Fitbit) accelerometers; the wearable devices Flex (Fitbit), the UP24 (Jawbone), and the Fuelband (Nike); an iPhone 5s (Apple) simultaneously running 3 iOS applications, Fitbit (Fitbit), Health Mate (Withings), and Moves (ProtoGeo Oy); and a Galaxy S4 (Samsung Electronics) running 1 Android application, Moves (ProtoGeo Oy).
“Data from smartphones were only slightly different than observed step counts, but could be higher or lower. Wearable devices differed more and one device reported step counts more than 20% lower than observed. Step counts are often used to derive other measures of physical activity, such as distance or calories burned,” the authors write.