Understanding sleep
REM sleep: what it is and when it happens
By Sömnlyftet · created with AI support Updated:
The main answer
REM is a sleep phase with rapid eye movements and an active brain. It recurs during the night and usually takes up more time later. REM and deep sleep are different parts of one night, not alternatives you need to choose between.
What does REM stand for?
REM means rapid eye movement. Brain activity during this phase differs in several ways from deep sleep. Dreaming can also happen in other sleep stages. Not remembering dreams does not show that you had no REM sleep.
The later part of the night matters too
REM periods generally become longer later in the night. Sleep is therefore not made of identical, interchangeable blocks. Deliberately cutting off the morning part because you have already slept for a few hours is not a reliable way to preserve everything you need.
Do not let a percentage make the whole judgement
A watch provides an estimate, and different products can classify sleep differently. Notice total sleep time and how you feel later in the day. Habits that leave enough room for sleep are more useful than trying to order a larger dose of one stage.
National Sleep Foundation · Consumer sleep technology (2026)
An illustrative example
A week of late evenings and early alarms leaves your nights short. Instead of trying to raise an app's REM score, you look at total sleep time and what is keeping you occupied at night.
A common question
Do more remembered dreams mean better sleep?
Not necessarily. Dream recall is not a simple measure of the whole night's sleep. Consider sleep duration, recurring patterns and how well your days are working.
Sources and authorship
The sources describe sleep and habits in general. They have not evaluated Sömnlyftet. The examples are fictional and illustrate an approach, not the results you will achieve.