Activity is determined based on data from the accelerometer (detects your arm movement) and the piezo sensor (detects your heart rate). This means if that your hands are not active enough during activity the accuracy of the device may decrease. For example, you may be walking, but if your hands are, for example, resting on a cart, or you are carrying a bag, or your hand wearing the band is in your pocket, the accelerometer will not detect any arm movement and it won't recognize them as an activity. The same applies to workouts in which your hands are not engaged in movement, such as a treadmill, cycle, elliptical, or weight training.
We do plan to add support for different types of physical activities and a sports mode in one of the next GoBe releases. Stay tuned to our social media pages for updates!