Every time Nokia Sleep detects you get into bed, the time will be logged in a Google Spreadsheet.
If
When I get into bed
This trigger fires every time your Withings Sleep detects that you get into bed, within the start and end time parameters that you specify.
Then
Add row to spreadsheet
This action will add a single row to the bottom of the first worksheet of a spreadsheet you specify. Note: a new spreadsheet is created after 2000 rows.
Explore more great ways to automate Withings Sleep and Google Sheets