If you rely on a fitness tracker to find out how many calories you've burned throughout the day, then you might be disappointed.
The Swedish school of Sport and Health Sciences took seven popular wearables currently available on the market and tested them: the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn and the Samsung Gear S2. For monitoring heart activity, the devices were great. In fact, most of them read back heart rates that were well within a 5 percent margin of error.
Author of the study, Anna Scherbina, says that the problem lies with high-intensity activities, and that fitness trackers have a difficult time clocking in how much you're actually burning.
"The error depends on the type of activity you're tracking. For activities like walking and sitting, the results are more accurate than for more intense pursuits, like spinning and running," she explains. "The point is, you're not burning as much as you think you are."
There are many factors that decide how much energy you're actually expending in a workout. Like if you're using the StairMaster - you're not burning as much if you're holding onto the railings compared to the guy who's doing it hands-free and exerting extra effort with each step to stabilize his body. Fitness level also plays a huge role into how many calories you burn. A freshman high school wrestler in their first year can barely get through their first match, but a senior All-American who's been doing it for years needs to push themselves way harder in training in order to even break a sweat.
Combine that with the fact that they believe they're burning way more calories than they actually are and you can see why some abandon all hope in calorie counting.