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

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.