Sleep glossary
REM sleep
Updated
Trackers may estimate REM, but home devices cannot see brain activity directly in the way clinical equipment can.
Plain-English definition
REM sleep is a sleep stage associated with rapid eye movement and vivid dreaming in many people.
Trackers may estimate REM, but home devices cannot see brain activity directly in the way clinical equipment can.
Why it matters
It helps readers understand tracker dashboards without treating stage estimates as exact measurements.
Buying relevance
Use this term as a practical buying clue, then check the current manufacturer wording, setup guidance, materials, and returns policy. It should not be treated as a medical claim or a guarantee of how a product will work for you.
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