Fitbit Surge

Fitbit announced today that it has changed the way it calculates and displays active minutes for users.

The company explained that its activity trackers will only count active minutes if a user participates in an activity for over 10 minutes, which is what the American Heart Association recommends. This will not affect the user's step count numbers.

"This 10-minute rule means that walking to refill your coffee might get you ahead in a step challenge, but it will no longer count toward your active minutes," the company explained. "It also means that from now on, your active minutes may sometimes appear lower than what you’re used to."

But, Fitbit said it would also add moderate minutes to its active minutes count. Previously, Fitbit just counted very active minutes when calculating a user's overall minutes. The company explained that the addition of moderate activity to the active minute count will impact users' historical data and will give users more credit for exercises like brisk walks.

While this change doesn't affect how activity is sensed by the device, it does change the way Fitbit users will view their activity, especially compared to how other activity tracking devices display and make sense of activity data. At the very least, a user that tracks their activity with more than one device or app will likely see a discrepancy between their Fitbit stats and other app and device data.

Lately, the accuracy of activity-tracking apps and devices has been a point of some contention. In early February, researchers at the University of Pennsylvania conducted a small study and concluded that activity tracking apps on smartphones are more accurate than fitness tracking wearables when it comes to step counts.

In response to the study, several activity tracking device makers, including Garmin, Misfit, Fitbit, and Jawbone, pointed out that it's more important if the device is consistent with itself. It gives a valid comparison of a user's steps yesterday to their steps today, even if that step count is a little bit divorced from reality.

Then, in March, Wired published a less rigorous study of activity tracker accuracy, after disputing some of the science behind the University of Pennsylvania study, and found activity tracker devices to be more accurate than activity tracker apps.