<br /> Millions of people wear some kind of fitness tracking device. But just how accurate are they?<br />They're accurate enough to be useful for most people for most purposes. But it also varies by what it is you’re trying to measure. Asst. Prof. Lisa Cadmus-Bertram University of Wisconsin-Madison<br />The shallow end of fitness tracking is a simple step count. It's better if the tracker is worn on the hip, not the wrist.<br />Devices that measure heart rate tend are good at measuring heart rate at rest but have much more variability during exercise.<br />And a recent meta-analysis showed that fitness trackers are not very accurate at measuring caloric burn. <br />
