Charge 3 and 4-Calories go backwards

[Tara68]

The calories in my Fitbit Charge 3 when synched with the app go backwards!  When I wake up in the morning the calories are around the 300 mark and then I watch it go backwards on the app.  This happens with exercise too.  I thought it was faulty and have purchased a Fitbit Charge 4 and the same thing is happening.  Can anyone advise what is happening.  Thanks.

Moderator edit:  updated subject for clarity

[JuanFitbit]

@Tara68 , Nice to see you here. Thank you for your message. 

I'm not quite understand the situation. Could you try to elaborate on it, and if possible attach screenshots to give me a better  idea what you mean?

See you around. 

[Tara68]

I’m unable to send a screenshot as I sync on my app on my iPhone and watch the calorie counter lose a couple of hundred calories. Eg I woke up this morning and the app said I had burnt off 344 calories and once synchro went back to 199

[JuanFitbit]

@Tara68 , Thank you for your reply and further information. With it I can make me an idea of what's happening. 

The Fitbit app calculates the burned calories during your sleep with help of your personal info (age, gender, etc) + your BMR. 

If you wear your tracker during your sleep you also record your heart rate, that might be slower as average you might burn less calories as the app initially calculated. After syncing with the data tracked with your Charge 4 the app will recalculate and update the results. 

Hope this helps.