1. Heart rate data is only recorded when the watch is being worn. It is normal to see gaps when the watch is not worn.
2. If the watch is worn loosely or incorrectly, the heart rate sensor may recognize it as not being worn, leading to missing heart rate data.
3. If the issue persists, press the Functional Crown on the watch to enter **Settings** > **System Menu** > tap **Restart** or long-press the crown and select **Restart** and check again.
4. In the CMF Watch app, go to the **Device** page and select **Device Upgrade** to update the firmware to the latest version for an improved experience.
5. If the above steps do not resolve the issue, press the Functional Crown on the watch to enter **Settings** > **System Menu** > tap **Reset** and check if the problem is resolved.
**Note**: Ensure that the back of the watch is clean, dry, and free of debris. The monitoring unit area should be in close contact with your wrist, maintaining a comfortable and snug fit. Do not apply any film to the back of the watch, as the sensors for detecting the human body may be obstructed, leading to inaccurate or incomplete readings of heart rate, blood oxygen, sleep, and other metrics.