Fitbit SimpleSleep Operations

(last update 2024-02-21  Version x.2.03 [Versa  & Sense only])     

Fascinating app, to track Sleeping position and related heart rate
Can alert to force a change of position after prolonged periods, or immediately
This can possibly help avoid Snoring or Apnea or with heart issues.

Requires a Chest Strap extension and uses a rotated screen for easy reading.


LiveTracking Main view
long look

Summary view

Graph view

Quick Guide

Note: How to use the watch and app

Attach the existing watch bands to the chest strap extension and
place it in the most comfortable position near the navel,
tighten the strap slightly to ensure a good fit but not too tight,
just enough it doesn't move in the night.
Ensure at least 50% battery to avoid it ending in the night.

Also make sure the watch has a Heart rate working before starting the app
in order to do proper averaging.

How to calibrate it

When lying flat on your back push the watch button, or
strong double tap the watch, to wake the display, if necessary.

ook at the horizontal reading by tilting the watch towards you
 it should read around zero and say "On back"
meaning it is in the correct central back position.

Note the approximate position with respect to the navel
and if necessary reposition by feel if you wake.

It is fairly tolerant of being off centre a little,

and that can be extended in the settings.


How to configure it

 If you have already started the app on the watch and done the settings on the phone,
see next section - configuration settings
 you won't need the phone for measuring, it is all done independently on the watch.
If not make the settings changes, though the defaults should be fine.

Before going to sleep, the optimal display timeout should be set to 60 seconds,
the watch should be set in sleep mode
from the watch Quick Settings or as a scheduled setting
then just before sleep, start the app to start recording the night session.

Now sleep as you normally would.
You can wake the watch to see the time with a press of the button.

How to record the Session results

In the morning take a photo of the Summary view and
Graph views to keep a record of the information before ending the App.
(Note: Ending the App clears the session for next time.)

Having the timeout set at 60 seconds will help this process.

If the app is exited, or ended unexpectedly, the session will be stopped.
It can be retrieved again by starting SimpleSleep
double tap the main view and tap on Previous session


Session recall can only be made for 5 minute after which
the new session will be recorded over it

If the Previous session is recalled no live recording will take place or be saved
exit the app and restart it to start a new session.

How to navigate the App

Both the Sense and Versa work with the button to advance to the next view,
also a quick single tap or swipe away from watch button will also navigate

Double tap the views to go backwards

In Graph view double tap goes to previous graph page, if any,
and single tap goes to next page, if any,
a button press. or swipe goes back to Main view.

While a graph is dynamically drawing navigation is not allowed.

To avoid losing a session exiting the app is special.
Double tap the
Main view and
 tap on the Tick to end the session and Exit the app,

any other action, button press, swipe away from button
or single or double tap or tap on X will go to the
Main view.

Covering the face with your hand or Long press any time will blank it.

Pressing the button will wake the display and revert to the Main view.
Graph view remains after display comes back.

Configuring Settings

Start the app on your watch and open the Gallery tile in the Fitbit app
click the SimpleSleep app and adjust the Settings

Alerting can be enabled / disabled
the duration of the alert can be set to a maximum of 60 seconds
Each sleep position can be adjusted separately,
by default 6 consecutive hours in each position are permitted
The app on the watch must be running and syncing to pick up any changes

Gallery tile app settings


Using screens

Screen navigation

Pressing the button or swiping from the button to the opposite side or
tapping takes you from screen to screen in rotation.

Live Main view


Shows large time for night viewing,
a quick count of the sleeping positions so far
sleeping position and
Heart rate in real time
with recordings
about once per minute

If the alerting is annoying double tap the bell to temporarily disable alerts.
Next time the App is started it reverts to the state it has been configured for

Summary view


At the top it shows the date recording started,
at the bottom it shows the
battery progress and start time - current time

The current durations and heart rate information is shown
for each sleep position and vertical positions for this session.

Double tap to return to
Main view or button press to show Graph view

Graph view


Up to 4 hours of information can be shown per graph page
heart rate versus sleeping position and durations are shown

To make it easy to follow each of the positions and HR have their
own colours as shown on the side

Each time the view is brought into focus you can see the new information
being added for the last incomplete graph page.

To switch between graph pages click on Previous or Next , if present
double tap or single tap on the face will also go to Previous or Next

Press the button, or swipe. to get back to the
Main view

Navigation away from a graph being drawn is not possible,
just wait for it to complete
when then count at the bottom stops or when the page is full.

Alert processing
(What's it used for?)

Should you suspect a sleep position is problematic for you
you can cause the watch to vibrate to force you to change position.

For instance, Apnea most often occurs when sleeping on your back
and you may want to limit sleeping time on your back, see example below.

This can bring relief to your partner, as you don't continue snoring so much and
you may have a better sleep.

If you turn on Alerts in the configuration settings,
set the continuous time for one of the horizontal positions accordingly.

Once the time is reached the watch will gently vibrate
this should cause you to move to another position, and will end the alert.

You can also end an alert by tilting the watch in any horizontal direction.
or pressing the button
If necessary double tap the
Bell till it shows disabled
which will temporarily disable alerting.
If the app is locked unlock it first.

Eg. Disable sleep on the back for more than 4 minutes at a time.
In the phone Settings for this app
set Back duration to 4 minutes,
turn on alerting
set the duration of the alert

Then every time you sleep longer than 4 minutes on your back it will vibrate.
If you wake and want to briefly lie on your back, double tap the

Bell this will stop it vibrating repetitively after every 4 minutes.

If you want to sleep again with it enabled again, double tap the disabled Bell,
which should enable, to confirm it is active again.

If you are having difficulties in the night and alerting was not set in the App settings
you can temporarily enable it by double tapping the Bell to turn it on.

Important Note:
Alerting cannot be altered in lock mode,
either from the watch face or from the app
However the times can still be changed from the App any time.

Tip: Any time the Bell is set active the Alerting settings will be shown briefly,
this enables checking them without the need for the phone.

Locking - Unlocking - Troubleshooting


In order to avoid false changes in the night, in addition
to the default protection, you can further lock the app,
Padlock is shown on the top row

1) To lock the app

  • From the Main view press and hold the watch face briefly, too long and the display blanks
  • The Padlock will start flashing
  • Press any watch button to engage the Padlock
  • The only function that will work in lock mode is the button to wake the display
  • Display timeout changes to maximum 8 seconds

2) To unlock, reverse the process

  • From the Main view press and hold the watch face briefly, too long and the display blanks
  • The Padlock will start flashing
  • Press the watch button to disable the Padlock

3) To not alter locking [ cancel flashing
Padlock ]

  • Hold the watch face briefly again, or
  • Cover the display with your hand

4) Don't panic if you can't get out of Lock mode or the app

  • Restart the watch by holding the button
  • for about 10 seconds, or
  • Go to the Fitbit App, Gallery tile
  • Uninstall and reinstall the app
  • but this shouldn't be necessary

Note: You may lose whatever session was being recorded.

Battery and monitoring issues

The extra monitoring use a bit more battery,
about ~1% per hour for a Sense and ~2% per hour for the Versa.

The Versa with a slower processor also takes longer to produces the graphs.
The graphing is CPU intensive so can cause shortened autonomy.
To save battery take a photo of the previous graphs once drawn.
The graphs are drawn dynamically.

It is important to ensure enough battery before a night's monitoring,
and to be on the safe side at least 50% is a good battery level.

Pay attention to the Summary view which shows the overnight battery usage
to get a better idea of usage with your particular watch settings.

Fitbit App Snore detection or SpO2 monitoring can use much battery
you can use this app to monitor sleep positions with them off or on

To improve things logout of the Fitbit app before sleep, unless you changed the settings,
 and make sure the watch is in sleep mode before starting the app
and cover the watch face with your hand when you no longer need the display.

The Estimated Oxygen variation graph in the Fitbit App Sleep tile may not be optimal
if the watch is moving too much and making irregular contact
it may not be able gather the information consistently

However Sleep should still record reasonably well under normal circumstances

Time format
  • 12/24 hr mode - to change format,
Use App Settings in the Fitbit app or
select the desired time mode
Submit and sync   

Restart & Version

Each time the app is started a new session begins using the parameters defined in it's App settings on the phone, and saved at end of session.

To see the app version switch to the Summary view, it is shown at the bottom


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SimpleSleep release history (V4 - Versa, V5 - Sense)

check this release history occasionally for new features or updates

Vx.2.03 -

  • Alert times shown briefly any time the Bell is enabled
  • Previous Session recall added
  • Display on/off times improved
  • Long press display blanking added
  • Haptic feedback improved
Vx.1.18 - 2023-12-28

  • Alert toggling disabled if locked
  • Alerting in the horizontal positions only
  • Locking / unlocking improved
  • Performance improvements
  • Horizontal Sleep angle emphasised

Vx.1.17 -

  • App lock added and performance improvements

Vx.1.16 - 2023-12-17

  • improved navigation and graphing

Vx.1.15 - 2023-11-20

  • Initial release