These studies were performed to clarify (1) the actual conditions concerning rotating shift schedules of nurses in Japanese university and college hospitals and to evaluate (2) some aspects of the physical and mental health, and (3) sleep profile of hospital nurses working on counter-clockwise shift rotation. Two questionnaire surveys and the OSA sleep inventory (OSA) were carried out. The subjects in the study (1) were a total of 80 nursing directors in university and college hospitals. The questionnaire covered 4 categories, such as the schedule most frequently adopted and reasons for using the schedule. The questionnaires were returned by 67 directors (83.8%). The subjects in the study (2) were 189 nurses working on three-shift work schedules at Asahikawa Medical College Hospital. The items in the questionnaire covered 7 categories, as follows: 1) feeling of sleep after each shift (8 items); 2) feeling of fatigue after each shift (30 items); 3) physical symptoms; 4) inter-personal problems; 5) all the items on Zung's self-rating depression scale (SDS); 6) all the items on the Horne and Ostberg morningness-eveningness questionnaire; and 7) 24 items on the Maudsley personality inventory. The questionnaires were returned by 156 nurses (82.5%), whose mean age and duration of shift-work employment were 27.2 +/- 5.1 and 5.0 +/- 4.3 years (mean +/- SD), respectively. For 152 nurses (97.4%) of those returning the questionnaire, the working schedule consisted of 2 consecutive night shifts and 2 consecutive evening shifts, following a variable number of day shifts (rapid and counterclockwise shift rotation). The subjects in the study (3) were 8 healthy nurses working on above-mentioned three rotating shifts at the psychiatric ward of Asahikawa Medical College Hospital, whose mean age was 29.4 +/- 5.8 years (mean +/- SD). All the subjects recorded their sleep-logs and underwent OSA everyday for 30 consecutive days. Of the 240 OSA data, 95 data (16 after day shift, 17 after the 1st night shift, 16 after the 2nd night shift, 15 after the 1st evening shift, 16 after the 2nd evening shift, 15 after day off) were analyzed. In addition to five of sleep factors in the OSA analysis, we evaluated the global score (GS), which represents subjective global feeling of sleep. In the study (1), 47 of 66 hospitals (71.2%) adopted rapid and counterclockwise shift rotation. The results of study (2) were as follows: 1) After the first night shift (diurnal sleep), the sleep problems were worst, and the frequency of taking sleep-inducing drugs was highest (12.6%); 2) Feelings of fatigue were the highest level after each of the two night shifts; 3) SDS score was relatively high (57.8 +/- 8.1, mean +/- SD); 4) The older the nurse, the greater the aggravation of both sleep problems and fatigue; 5) Sleep problems after day shifts were worse and SDS score was higher in nurses classified as "nightowls" compared to those in nurses classified as "morning people"; and 6) There was no difference between introverts and extroverts in sleep problems, fatigue or SDS score. The results of study (3) were as follows: 1) In 3 of sleep factors (Sleepiness, Integrated sleep, sleep initiation) and GS, there were significant differences among each rotating shift schedule including day off; 2) The highest score in five of sleep factors and the highest GS were noted after the 2nd night shift (nocturnal sleep), and the lowest after the 1st night shift (diurnal sleep); and 3) The younger subjects (n = 4; mean age, 24.5 years) showed a higher GS compared with that of the older subjects (n = 4; mean age, 34.2 years).
