Your phone can measure your movements but overestimates your daily steps.
Your phone uses GPS to track distance travelled. But try disabling it and you’ll notice that fitness apps will still give you step counts. They do this using your phone’s built-in sensors, which usually include an accelerometer and a gyroscope.
Accelerometers measure acceleration, while gyroscopes help track the direction your phone is pointing in, usually by measuring the movements of tiny components inside them that generate electric signals as they move. According to the experts, the best place to count steps is at the hip and so putting your phone in your pocket should provide a more accurate count than putting it in your bag.
A study published last year tried to verify the accuracy of smartphone apps for step-counting, comparing results from a medical-grade accelerometer worn on the hip to those from the WeRun app. 103 people used both at the same time, for three, week-long bouts of step-counting. The study showed the app overestimated the average daily step count of around 8,500 steps by close to 500 steps.
Read more:
- Forget 10,000 steps – walking just 5,000 is enough to lower your risk of death, says science
- Dr Michael Mosley: Ditch your fitness tracker – there’s a better way to get fit
- Can the government track you if you have a GPS-enabled mobile phone?
- How to choose the best fitness tracker
Asked by: Amy Webster, age 15 via email
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