It is normal to only vibrate and not light up the screen when there is a new notification. Waking up the screen frequently due to many notifications can have a certain impact on power consumption and an excessive disturbance. Please manually light up the screen to view the notifications.
To light up the screen when receiving notifications, please refer to the following steps:
1. Open the [Mi Fitness] on your smartphone;
2. Go to [Device];
3. Tap on [App notifications];
4. Turn on [Wake screen].