EFFECT OF SHIP NOISE ON SLEEP

Abstract The effects of a steady sound level of 65 dB(A) from a diesel ship engine on nocturnal sleep were studied using polygraphic and subjective sleep parameters. Three healthy men, aged 29 to 33 years, participated in the experiment. Sleep polygrams and the sound level in a sleep laboratory were recorded for each subject for five exposure nights and five control nights. The following morning, the subjects answered a self-rating sleep questionnaire (called the OSA) and underwent simple reaction time tests. The percentage of S2, SREM latency and the REM interval increased, while %SREM decreased during the noise-exposed nights as compared with corresponding values on the control nights. Other parameters of sleep EEG were unchanged. Five scale scores for OSA, sleepiness, sleep maintenance, worry, integrated sleep feeling and sleep initiation deteriorated significantly on the noise-exposed nights as compared with the control nights. Canonical discriminant analysis was conducted using 19 sleep parameters. The standard partial regression coefficients of %SREM, %S2 and %S1 were somewhat higher than other parameters. It was suggested that exposure to the 65 dB(A) ship noise exerted adverse effects on nocturnal sleep, subjectively and in part polygraphically (REM sleep and shallow sleep).