小学校高学年児童の睡眠・覚醒リズムと自律神経活動の関係 : 6事例の報告

The purpose of this study was to clarify the relationship between sleep-wake rhythms and autonomic nerve activities using actigraphy and heart rate variability（HRV）analysis. Subjects were comprised of six children who were in the fourth to sixth grade levels of elementary school（four boys and two girls）. The study was conducted between January and December 2015. The data collection procedure was performed following the Private Information Protection Law, with approval from Tokushima University Hospital Ethics Board（approval number 2021）. These subjects were evaluated in an Attentive-Care-Needed stress state based on the PSI（Public Health Research Foundation Type Stress Inventory）and PSQI-J（Pittsburgh Sleep Quality Index, Japanese Version）. In analyzing their sleep-wake rhythms, autonomic nervous activities were determined using an actigraph and HRV through RR interval sequence electrocardiography. The results of actigraph data of sleep efficiency in Subject Number 6 was low（76.47％）. Regardless, the subject experienced subjective sleep satisfaction. However, Subject Number 2, insisted that she could not easily wake up in the morning because of being sleepy. Low Frequency（LF）/High Frequency（HF）data indicated sympathetic nervous activity showing that all subjects had significantlyhigher LF/HF value during wakefulness than when asleep. HF data indicated parasympatheticactivity of five out of the six children showing significantly higher value during sleep than when awake. Subject number 3 expressed that he was sleepy and could not get up in the morning,and also had trouble going to and maintaining sleep. However, this subject’s results of the PSQI-Jindicated that he had no problem expressing subjective sleep satisfaction. Furthermore, in the actigraph and HRV analysis, findings showed that subjects had good sleeping patterns. These findings strongly signify the importance of determining the sleep-wake rhythms of school children based on data from subjective and physiological evaluation methods.