Kawada T, Suzuki S, Aoki S, Ogawa M, Kimura K
Nihon Eiseigaku Zasshi. 1989 Feb;43(6):1109-15. doi: 10.1265/jjh.43.1109.
One healthy twenty-eight-year old man was exposed all night to intermittent, rectangular pink noise of 5 and 10 seconds' duration 9 times per hour. The peak levels prepared were 40, 50 and 60 dB(A). One level of the noise was exposed throughout a single night. Ten non-exposed control nights were also prepared. The sleep electroencephalogram was analysed by a microcomputer system of the authors' devising. Increases of sleep latency and stage W, and decreases of the REM stage and mean sleep depth, especially in the early sleep hours, were confirmed in the sleep polygraph of the 60 dB(A) exposure but not in that of the control, 40, and 50 dB(A) exposures. It was concluded from these results that the intermittent 60 dB(A) pink noise exposure clearly disturbed sleep, and that the threshold of the effect should exist between 50 and 60 dB(A) exposure.
