1980 Volume 11 Issue 4 Pages 327-341
Polygraphic recordings of diurnal sleep and night sleep were obtained after night duty and day duty or off-day, respectively, studies were performed on from 5 hospital nurses working by on three-shift-system and on male 5 guards on alternate-day shift system. Sleep patterns in the above two groups were compared and following results were obtained. 1) In diurnal sleep after night duty, time in bed and total time of sleep were shortened, number of wakenings increased, REM sleep latency shortened, the first REM duration prolonged, and S3 and S4 sleep latency significantly prolonged as compared with night sleep. 2) In diurnal sleep, the appearance of REM sleep in sleep onset ie., the SOREMP (sleep onset REM period) was observed in 3 of 10 subjects. 3) In diurnal sleep, the distribution of sleep stages was clearly different from that in night sleep ; thus in the former, REM sleep amount during the first 120 to 180 mins. after sleep onset was increased, the amount of S4 sleep significantly decreased, and the amount of REM sleep was greater in the early period than in middle period. It can be conjectured from above results that REM sleep may be dependent on the circadian rhythm, and S4 sleep on the length of prior wakefulness. On the other hand, pulse rate showed a higher level in diurnal sleep than in night sleep, and internal desynchronization of sleep stage was visible between the two.
