Of course, deep sleep and shallow sleep alternate. Before the mi band, we didn't know how we slept or how we rested. Now we can quantify it. As long as you open the APP on your mobile phone, you can see the principle of mi band recording at a glance.
Although everyone's sleep state is different, there are still rules to follow in human sleep state. The main judgment basis of the bracelet is the movement variable from falling asleep to falling asleep and then waking up.
Everyone's body always changes from going to bed to really falling asleep. When the bracelet is worn on the wrist, it will inevitably produce various displacements with the change of body movement. When the gravity point changes, the bracelet will record and judge whether the person is sleeping.