A Comparison of Nighttime Sleepiness, Performance, and Body Temperature between Morning-Type and Evening-Type Persons

아침형과 저녁형 사람에서 야간의 졸리움, 수행 및 체온의 비교

Objectives: The main purpose of this study was to investigate the possible differences in sleepiness, performance, and body temperature during the night between morning(M) and evening(E) type subjects. Methods: After a survey study, to verify the validity and reliability of the Korean translation of the Home' and $\ddot{O}stberg's$ Morningness-Eveningness Questionnaire(1976), 8 extreme M-type subjects(3males, 5 females) and 8 extreme E-type subjects(3 males, 5 females) were selected from the university student population who had participated in the survey study. All subjects underwent sleep latency test and a battery of performance tests at intervals of 2 hours through the night, from 23:00 to 07:00. Oral temperature of each subject was taken every hour from 21 : 00 to 8 : 00. Between the testing times, the experimenters ensured that subjects remained awake. Results: More profound sleepiness was found in the M-type compared to the E-type throughout the night, with significant differences in sleepiness occuring at 23:00 and 01:00 hours. Overall performance efficiency tended to be lower through, the night in the M-type than in the E-type on all tests. A difference in time of temperature minimum between the two types was not noteworthy. Rather, there appeared to be a substantial difference in temperature level during the declining phase, with the temperature of the M-type being lower than that of the E-type. Conclusions: These results indicate the existance of a temporal relationship between sleepiness, perfonnance and body temperature during night work. Since the M-type exhibited greater sleepiness and lower performance efficiency overnight than the E-type, it may be assumed that the E-type is more suitable for and tolerable to night work. There was some discussion of the limitations in generalizing these results together with some suggestions for future studies.

본 연구는 야간에 아침형과 저녁형사이에 졸리움의 정도, 수행능력, 체온변화의 차이를 객관적으로 검증하고자 하였다. Horne과 $\ddot{O}stberg's$의 아침형-저녁형 설문지(8)의 한국어 번안 설문지에 대 한 신뢰도와 타당도를 검증한 후, 극단적인 아침형과 저녁형 각 8 명을 선발하여 야간에 수면잠복 검사, 다양한 수행검사, 체온 측정을 일정 간격으로 실시하였다. 결과는 전야간에 걸쳐서 아침형군이 저녁형군보다 졸리움이 훨씬 심하였고, 수행검사의 성적도 더 낮았다. 체온은 새벽의 최저점에 이를 때까지 아침형군이 저녁형군보다 더 낮은 상태를 유지하였다. 이러한 결과는 야간에 졸리움, 수행, 체온 사이에 시간적인 관련성이 있음을 가리키며 저녁형이 야간근무에 더 적합할 수 있다는 가정을 지지한다.