Sleep states refer to the different phases of sleep that occur throughout the night. These phases are primarily divided into two categories: REM (Rapid Eye Movement) and NREM (Non-Rapid Eye Movement) sleep. NREM sleep is further divided into three stages, ranging from light sleep to deep sleep, while REM sleep is associated with vivid dreaming and increased brain activity. During a typical sleep cycle, a person transitions through these states multiple times, usually lasting about 90 minutes each. NREM sleep helps with physical restoration and memory consolidation, while REM sleep plays a crucial role in emotional regulation and cognitive functions. Understanding these sleep states can help improve overall sleep quality.