Charge 5 registering no cardio except peak during run

[Wischgesa]

During run in spite of showing cardio and peak heart rate throughout entire workout cardio minutes showing as below fatburn 

[DavideFitbit]

Welcome to the Fitbit Community forums, @Wischgesa.  

Thank you for sharing this information about the issue you're experiencing with your Charge 5. 

If you haven't done so already, I recommend that you try restarting the device using the three pulse restart method mentioned here below:

1. Connect your device to the charging cable. For instructions, see How do I charge my Fitbit device?
2. Press the button located on the flat end of the charger 3 times (end of the USB cable), pausing for 1 second between presses. Then wait 10 seconds or until the Fitbit logo appears.

In addition, please follow the instructions in this article to improve the accuracy of heart rate information and check the information mentioned here about other factors that could affect your heart rate reading, this has been useful to other users who have experienced something similar. 

Hope this helps, I'll be around.