What is a smart wristband used to determine a user's sleep status?

At present, the sleep monitoring function of smart bracelets on the market is determined by the three-axis acceleration sensor embedded in the bracelet. This type of sensor can effectively sense whether the bracelet is moving and the direction of movement.

So, the vast majority of wristbands on the market use the following methods to determine whether the wearer is asleep and the depth of sleep: if the wearer does not engage in any vigorous activity for a period of time (such as ten minutes or half an hour), it is possible to enter a sleep state. If the wearer has very little or no activity during this period, the bracelet will recognize that they are in deep sleep; If there is some activity but not particularly intense activity, the bracelet will recognize that it is in light sleep during this period. This method also has a specialized name in academic research, called an Actigraph.

In principle, smart wristbands cannot truly distinguish whether users are lying still or when they fall asleep. However, in practical use, users are not likely to feel such problems. The reason is: 1 The wearer needs to maintain a constant posture for a period of time (such as ten minutes or half an hour) in order to be considered asleep. And the vast majority of users generally do not lie in bed motionless for such a long time just to do such a test; If you don't wear a smart bracelet and place it on the desktop, there are usually several fixed angles. The algorithm for sleep monitoring can determine that when the wristband is in these positions, it will not be sleeping no matter how long it is placed;

Some smart bracelets provide an estimated heart rate based on photoelectric signals. When the user is not wearing it, the smart bracelet will not monitor heart rate; When users enter sleep, their heart rate generally decreases; When users sleep deeply, their heart rate drops even lower. Such smart wristbands help improve the accuracy of monitoring sleep time and depth.

Finally, it should be noted that regardless of whether the heart rate monitoring function is present or not, the accuracy of Actigraph monitoring sleep cannot accurately reflect the true sleep status 100%. However, for the vast majority of users, wearing a smart wristband to monitor sleep basically does not affect sleep quality, and the monitoring results are basically reasonable, so it can be a simple and feasible reference method.