Many fitness trackers measure health data such as your heart rate and the number of calories you burn, but can you really trust the information these devices provide?Your fitness tracker may accurately measure the heart rate but may misguide you on the number of calories you burnt, researchers say.
A team of researchers from the Stanford University in California evaluated the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn and the Samsung Gear S2.
They analysed information from 60 volunteers who wore up to four fitness trackers at once while they walked or ran on a treadmill, or cycled on a stationary bicycle.
Then, they compared the data from the trackers with data from the standard medical equipment that scientists use to measure people’s heart rate and calorie burning in health research.While these devices measured heart rate with an error rate of less than 5 per cent, none of the seven devices measured energy expenditure accurately.
Even the most accurate device was off by an average of 27 per cent and the least accurate was off by 93 per cent, the researchers said.
“The heart rate measurements performed far better than we expected, but the energy expenditure measures were way off the mark. The magnitude of just how bad they were surprised me,” said Euan Ashley, Professor at Stanford University.
As these devices are not up to the same standards as medical-grade devices, it’s hard for doctors to know what to make of heart-rate data and other data from a patient’s wearable device, Ashley said.
The findings were published in the Journal of Personalized Medicine.
Although manufacturers test the accuracy of activity devices extensively, it’s hard for consumers to know how accurate such information is or the process that the manufacturers used in testing the devices.
The take-home message is that a user can pretty much rely on a fitness tracker’s heart rate measurements. But basing the number of doughnuts you eat on how many calories your device says you burnt is a really bad idea, Ashley said.