You can only import sleep data to Pokémon Sleep after linking Pokémon Sleep with a data source app (such as Samsung Health and Fitbit) and then to Health Connect.
Any sleep data recorded prior to linking Health Connect to Pokémon Sleep cannot be imported into Pokémon Sleep.
In Pokémon Sleep, sleep data recorded without sleep stages (i.e. awake, REM sleep, light sleep, deep sleep) cannot be used. Sleep data should be 90 minutes or more and contain sleep stages to be registered properly in Pokémon Sleep.
Data with sleep stages
Data without sleep stages
For Fitbit and Pixel watch devices, if the recorded sleep is less than three hours, your sleep stages will not be logged and you will not be able to import that sleep data into Pokémon Sleep.
Sleep data that is manually edited in Health Connect cannot be imported into Pokémon Sleep. Be sure to sync with Pokémon Sleep without editing your sleep data.
Device and app information shared here are for your convenience. Please see the device’s or app’s official support page for the latest information.
• Fitbit
https://www.fitbit.com/global/us/setup
• Samsung Health
https://www.samsung.com/us/apps/samsung-health/#Sleep
• Health Connect
https://support.google.com/android/answer/12201227?hl=en