First of all, please confirm whether the watch and APP are the latest version. If they are not the latest version, please upgrade them to the latest version.
To solve this issue, please refer to the following details:
1. Sleep data is not recorded. If the wrist movements are more or very unstable, the watch will mistake it as non-sleep, resulting in non-recording of sleep;
2. If the sleep time is less than 15 minutes, the watch will not monitor the sleep, and sleep data will not be recorded at this time;
3. Sleeping on subways, high-speed trains, buses and other transportation vehicles will not be recorded due to the shaking or acceleration of the transportation vehicles;
4. Too loose wearing will lead to abnormal sleep monitoring. It is recommended to ensure that the watch is upward when wearing. Wear it a little behind the wrist bone, and do not press the device on the wrist bone. Adjust the strap to ensure that it fits the skin to wear. Avoid wearing too loose or too tight, resulting in inaccurate sleep data detection;
5. The watch is in a relatively quiet state, and there is a movement range similar to sleep, which makes the watch misjudge it as a sleep state, resulting in a false increase in sleep duration. For example, when you watch TV, play with your mobile phone, or read a book in a lying position before going to bed, you will be mistaken as asleep by the watch. The principle of sleep is to monitor sleep through the principle of heart rate variability. The heart rate sensor monitors changes in light. Therefore, when the light changes received by the device sensor are similar to those of the wrist, it will be determined that the watch is worn, and sleep monitoring will be carried out, resulting in sleep data and sleep time differences from actual sleep;
6. The watch cannot display the sleep of the previous day. The standard range of sleep data of the day is the data from 00:00 of the previous day to 24:00 of the same day. The sleep wake-up time of the day is attributed to the same day from 00:00 to 24:00. The watch only shows the sleep fragments of the day. If you have a sleep before 00:00, you can check it in the APP.