Whistle uses a three-axis accelerometer (just like your human activity monitor or smartphone does) to estimate the total amount of energy your dog expends each minute and quantifies this activity into Whistle Activity Points. 

Since your dog will occasionally shift position or roll over even when resting, we consider minutes in which your dog achieved less than a certain amount of points in that minute as minutes of rest. 

Because we didn’t want to just set that threshold arbitrarily, we performed studies where we videotaped several different dogs at night and set the thresholds to not award minutes of activity when the dogs were resting or just shifted slightly.