Does the Bluetooth on the phone need to be on when using the Xiaomi Smart Band 8?

You can refer to the following steps for Bluetooth usage:
1. Step counting, sleep & heart rate monitoring, stress/blood oxygen detection, vitality, breathing training, and cycles can be independently recorded without a mobile phone. It is necessary to regularly connect your phone to synchronize exercise health data. It is recommended to connect your phone to record trajectories during exercise;
2. The functions of stopwatch, alarm, focus, calendar, world clock, etc. do not require Bluetooth to be constantly turned on.
Due to the need for continuous communication between the phone and the band, functions such as call reminder, app notification reminder, phone search, schedule, weather, band search, music control, and remote photography need to be turned on to maintain Bluetooth connection between the wristband and the phone.
Note:
To better use the band, it is recommended to keep the Mi Fitness APP running in the background. To avoid removing the app in the background, please set it according to the requirements in the App >> [Device] >> [Background permissions] >> [Select “No restrictions” in Background settings].
iOS is unable to add background protection to applications. If an app enters the background and is removed, the system Bluetooth connection will not be disconnected in the background. Message notifications can be used normally. Other synchronized data applications (weather, sports and health data synchronization, schedule, etc.) need to be reopened to use the mobile sports and health app.
Enabling the power-saving mode on iOS will cause a decrease in the stability of the system's Bluetooth connection and result in disconnection.