When it comes to measuring heart rate and calories burned, not all fitness trackers are created equal, based on the findings of a scientific study that pitted the top wearables on the market against each other.
The in-depth study conducted by researchers at Stanford University was published today, revealing that Apple Watch is the most accurate wrist-worn tracker on the market, but it’s still far from perfect.
In their paper titled “Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort,” researchers evaluated the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn, and Samsung Gear S2.
The study found that the wrist-worn trackers had the lowest error rate when a person was cycling. Walking provided the highest amount of errors.
Six of the seven devices tested all achieved a median heart rate error below 5%. Tracking calories burned is much tricker though. Not a single device tested had an error rate below 20 percent, so if you’re trying to use your Apple Watch or FitBit to count calories, you probably need to find a more accurate method.
Source: Cult of mac