健常女性における起床のタイミングと起床後の身体的反応—REM期とNREM期に起床を促した場合の比較

Timing of Wake-Up and Response by the Body in the Morning in Females: The Comparison of REM and NREM Arousal

要旨

　目的：本研究は，より良い朝の目覚めを促進する基礎的研究として，異なる睡眠段階で起床を促した後の身体反応の違いについて検討した．

　方法：被験者は15名の健常女性とした．各被験者の実験日は3夜（第一夜，REM期・NREM期起床条件下）とし，起床後にP300と反応時間の測定を行った．また，5名の被験者は正午前にも同様の測定を行った．分析は，起床直後の両条件間の比較と各条件内での起床直後と正午前の比較を行った．

　結果：起床直後のP300潜時では，両起床条件間に有意差が認められた．各条件内での起床直後と正午前の比較では，REM期起床条件下でボタン押し反応時間（音刺激）とジャンプ反応時間に，NREM期起床条件下ではボタン押し反応時間（光刺激）に起床後から正午にかけて有意な短縮が認められた．

　結論：REM睡眠段階で起床を促すと認知や注意がNREM期よりも早く反応することが分かり，その後の身体反応が良く，日中の活動がスムーズになる可能性が示唆された．

　Purpose: The purpose of this study was to examine differences in physical responses after arousal at different sleep stages to promote better physical reactions after awakening and efficient daytime activities.

　Methods: Fifteen healthy women were monitored for three nights. On night 1, the subjects were aroused at different sleep stages [non rapid eye movement (NREM) and REM sleep]. After arousal, P300 and simple reaction times were measured in each subject. In addition, P300 and simple reaction times were measured before noon in 5 subjects. Analyses were performed comparing the measurements obtained immediately after arousal under NREM and REM sleep and those obtained immediately after arousal and before noon under NREM and REM sleep.

　Results: There was a significant difference in P300 latencies immediately after arousal under NREM and REM sleep. Comparison between the measurements immediately after arousal and before noon under the same conditions showed that arousal during REM sleep was associated with significantly shorter push-button (auditory stimuli) and jump reaction times, and arousal during NREM sleep was associated with significantly shorter push-button reaction time (photic stimuli), both before noon and at arousal.

　Conclusion: Arousal during REM sleep was associated with faster cognitive and attentional reactions than arousal during NREM sleep, suggesting that arousal during REM sleep could improve physical reactions after awakening and promote efficient daytime activities.