Habituation of sleep to road traffic noise assessed by polygraphy and rating scale

The effects of road traffic noise on sleep and habituation of sleep to road traffic noise were assessed by polygraphic sleep parameters and self-rated sleep scores. Seven male students aged 19 to 21 were tested each for a total of 17 nights by being exposed all night to recordings of road traffic noise with peak levels of L-max = 71.2 dB(A), L-eq=49.6 dB(A) and L-AE=94.1 dB(A) in an experiment room. Sleepiness, sleep maintenance, worry and integrated sleep feeling, which are subjective assessments, became worse and reaction time after sleep increased due to exposure to the noise. A significant increase in %Stage 1 and a decrease in %REM were observed, suggesting the road traffic noise had an effect on sleep. Habituation to road traffic noise during sleep was observed clearly in subjective sleep scores, but the polygraphic parameters showed little habituation to the noise with considerable individual variation.