Your Smartphone App Is Probably Missing Some of Your 'Steps'
A small study conducted by researchers at the University of British Columbia in Canada suggests that pedometers built into iPhones miss about 1,340 steps during a typical day compared with accelerometers that are worn on the waist. Health app accuracy is becoming increasingly important as more and more people – including medical professionals – are using them to track fitness levels and other health information.
The two-part Canadian study involved 33 participants. In the laboratory portion of the study, participants carried two iPhones, one personal and one provided by the lab, and walked on a treadmill for 60 seconds at various speeds. The step counts on the two phones were compared and the participants’ steps were also counted manually. According to the researchers, personal iPhones underestimated steps by 9.4 percent and the shared phones underestimated steps by 7.6 percent at the slowest walking speed. At faster walking speeds, the iPhones were less than 5 percent inaccurate.
For the second part of the study, participants wore accelerometers on their waists for three full days and recorded iPhone step readings at the beginning and end of each day. At the end of the study period, the iPhones underestimated the data from the accelerometers by about 21.5 percent – 1,340 steps per day.