A difference between morning-type and evening-type on electro-dermal activity, and improvement of sleep phase in evening-type by bright light exposure

研究了强光照射对日本大学生相位延迟睡眠的改善作用。首先对369名晨型、中间型、晚型学生进行睡眠问卷调查，平均年龄20.6±1.69岁，其中晨型19人，中间型261人，晚型89人。夜间睡眠时间和觉醒时间的不规则性明显高于其他类型。在三种类型中，夜班学生摄入咖啡因的量最多。与晨型学生相比，晚型组学生的疲劳感更强，身体状况良好的程度更低。其次，对7名身心健康的学生进行了强光照射和非强光照射的实验。采用多重睡眠潜伏期测验、主观嗜睡量表(Stanford嗜睡量表、Kalolinska嗜睡量表等)进行测试。我们利用心率变异性的时间序列数据分析了自主神经系统的指标。18时，在强光条件下，Kalolinska嗜睡量表的主观嗜睡度比在室内灯光条件下的要低。在两种光照条件下，自主神经系统的指标没有显著差异。白天暴露在强光下一天被认为对昏昏欲睡的影响有限。

We investigated the improvement of phase-delayed sleep inJapanese university students by bright light exposure. First, 369 students (average age20.6±1.69）who were 19 morning type, 261 intermediate type and 89 evening type were analyzed in the sleep questionnaire. Initiating sleep time and wake time was more irregular in evening type than in other types. Evening-type students took the most volume of caffeine in three types. Evening-type students had more fatigue and less feeling of good health compared to morning-type students. Second, seven physical and mental healthy students were participated in the experiments with and without bright light exposure. They were tested Multiple Sleep Latency Test, subjective sleepiness scales (Stanford sleepiness scale, Kalolinska sleepiness scale and so on). We analyzed the indicator of an autonomic nervous system by time series data of heart rate variability. Subjective sleepiness on Kalolinska sleepiness scale was decreased on bright light codition compared to that on room-light condition at 18 o'clock. There were no significant differences on the indicator of an autonomic nervous system in the two light conditions. Bright light exposure during daytime for one day was thought to have the limited effects on sleepiness.