Glossary of Sleep-related terms

NREM Sleep (Non-Rapid Eye Movement, Non-Rem)

All sleep stages other than REM sleep; made up of sleep stages 1 through 4. Characterized by a slowing of brain waves and some physiological functions. A state that lacks the visible motility of rapid eye movements and twitches. See Sleep Stages.1 Usually about 75% of the night is spent in NREM Sleep.2