Deep Sleep Measurement

Hi there.

Why is there deep sleep Measurement of SAA so different to all other tools I tried so far.
On SAA I have 50% deep sleep on all others at most 5-10%
Is there any information about that?

I’m using a Galaxy watch 4 und my smartphone


Here and here you can see how it measures sleeping.

I think the other apps you use are wrong. 5-10 % is too little.


Thanks for the Info.
Samsung Health defaults are 9,5-12,5%. MiFit ist around 10% and Fitbit as well.
So only SAA fall out of line.

Hello, deep sleep isn’t define anywhere in fact we have been pioneering this. On a PSG you do not have deep sleep but N1-N3, REM and awake. Also we do not have so many sensors, but typically just actigraphy or maybe HR. So it is basically about where you draw the threshold line.

Please read about how we are doing it here:

Many thanks…

@Guido_Neumann I think this may be in fact a GW4 specific issue. When I was testing the new Wear OS 3 ready Sleep as Android app on the Galaxy Watch 4 I also notice I’m getting less deep sleep on GW4 than on my TicWatch 3 Pro in the very same setup with the very same app and algorithm. I spend a week working on this - trying various setting of the sensor, for instance match faster update rate on the sensor (which of course affects battery) etc… But could not improve the data. During testing with debugging attached I noticed that the sensor sometime gets into a state where it starts repeating the data already sent which we do not see on any other watch. This made me believe that this is actually some bug in the sensor batching implementation by Samsung which may get fixed by Samsung eventually. It may also be soem battery optimization where the sensors stops gathering data in some situations. It may have also just a problem of my particular device, hard to say. Just want to recall that I have tested many Wear OS device and have seen this issue only on GW4 with the very same code on our end, so this made me believe we cannot fix it on our end.

Anyway based on this GW4 experience I have made some minor changes in the algorithms which may help in cases where we are getting incomplete data. This can also occur when for instance you are too far from your Sleep Phaser, or your phone is not able to emit sufficient volumes of ultrasound in Sonar, or your phone - using accelerometer - is further from your body… if you would be willing to give it a try, please sign up for the BETA…

Hi Petr.

Thanks for the detailed Information.
On my GW4 i cannot confirm that the deep sleep is less compared to other watches i used before. The only thing that i dont understand is, that nearly all other algorithms out there have significant lower deep sleep values. But if there is no global rule for it, anybody can do their own stuff.