The body will naturally cycle through stage 2 before deep sleep, so one of the best ways to know if you got enough of it is to simply assess how you feel in the morning. However, Willeumier notes, “It’s difficult to say unless you’re going for a sleep study,” and even some sleep trackers aren’t always reliable.
Essentially, if someone’s getting a full night of quality sleep, they had to go through stage 2 to get there. And if you’re waking up a lot throughout the night, or wake up feeling tired, it could indicate you’re not getting enough of stage 2.
The caveat is, it could also indicate you’re not getting enough REM or slow-wave sleep. Long story short, the only way to know for sure you’re getting enough stage 2 sleep specifically, Willeumier says, would be in a lab. But generally speaking, it comes back to overall sleep quality and good sleep hygiene.