What's the difference between deep sleep and motionless sleep?

[Jackie Poluck]

I am trying to track my deep sleep on my Samsung galaxy watch
but 2 nights ago the data changed to motionless sleep. Last night it showed deep sleep again, does anyone know the difference? Also can you go back and review previous daily sleep data?

 

[chanchan05]

That's probably Stage 2 Sleep. Sleep has 4 stages.

https://www.healthline.com/health/how-much-deep-sleep-do-you-need#stages