英和和英

one of 5 parts or stages of the sleep cycle based on the type of brain activity that occurs during the stage. during stages 1 to 4, a person will feel drowsy, fall asleep, and move into a deep, dreamless sleep. stage 5 is called rapid eye movement (rem) sleep, and it is during this stage that dreams occur. during several hours of normal sleep, a person will go through several sleep cycles that include rem sleep and the 4 stages of non-rem sleep (light to deep sleep).

睡眠の段階ごとに発生する脳活動の種類に基づく睡眠サイクルの5段階の1つ。睡眠期1～4で、人は眠気を催し、眠りに落ち、夢を見ない深い眠りに入る。第5段階はレム（rem）睡眠と呼ばれ、この段階では夢を見る。人は正常な数時間の睡眠において、レム睡眠と（浅い眠りから深い眠りへの）4段階のノンレム睡眠からなるサイクルを数回繰り返す。