Elsevier

Applied Acoustics

Volume 71, Issue 9, September 2010, Pages 870-875
Applied Acoustics

Effects of different noise combinations on sleep, as assessed by a general questionnaire

https://doi.org/10.1016/j.apacoust.2010.05.004Get rights and content

Abstract

In the present study, the effects of different noise combinations on sleep were assessed in two contexts, with a single noise source and with combined noise sources. Road traffic noise, and construction or movie noise combined with road traffic noise were used as the single noise source and the combined noise sources, respectively. When the sound pressure level of road traffic noise was kept constant, levels of the construction and movie noise were changed. Twenty participants were followed for approximately 2 weeks, during which their sleep was evaluated using a questionnaire, including questions on sleeping behavior, premature awakening, and subjective responses. The results showed that the combined noise sources including construction noise decreased the number of participants who fell asleep within an hour and increased the number that were awakened prematurely compared to the effects of road traffic noise combined with movie noise. However, similar tendencies were observed while evaluating sleep quality, sleep disturbance, and annoyance.

Introduction

Environmental noise causes a variety of adverse health effects such as annoyance, speech interference, and sleep disturbance [1]. Moreover, nocturnal noise causes premature awakenings, difficulties in falling asleep, as well as a decrease in subjective sleep quality. Noise-induced sleep disturbance has been investigated through field surveys and laboratory experiments [2], [3], [4], [5]. A few studies have compared field results with those from a laboratory and have concluded that laboratory experiments did not exaggerate the effects of noise on sleep [6], [7].

In order to measure the adverse effects of noise on sleep, a wide range of methods has been used. In several field surveys, premature awakening, referred to as behavioral awakening, was measured [2], [3]. Participants were asked to press a button when they were awakened. EEG data from polysomnography and motility (gross body movement) were applied as a more sensitive measure of disturbance than that of simple awakening [8], [9]. In addition to objective measurements such as awakening, EEG, and motility, the questionnaire survey has been used for subjective evaluations of sleep [10], [11]. Subjective evaluations of sleep were often obtained in conjunction with more detailed sleep measurement methods by having participants complete evening or next-day questionnaires.

Most previous studies on sleep disturbance have focused on transportation noises, especially road traffic and aircraft noise [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]. However, recent studies have dealt with various kinds of environmental noises in laboratory experiments because most residents are exposed to conversation, songs, and noise from construction, as well as road, aircraft, and railway noises. Kuwano and Mizunami [12] used a simulated air-conditioner noise, Karaoke song, conversation between two people, as well as road traffic noise. Namba et al. [13] investigated the sleep disturbances caused by meaningful sounds. However, most of these studies dealt only with a single noise source, with the effects of combined noise sources being rarely investigated. Recently, the adverse effects of combined noise sources have been reported in terms of annoyance and speech interference because community noises are concurrent [14], [15], [16]. There are also possibilities that residents are exposed to concurrent noise during sleep. Therefore, combined and single noise sources should be considered in sleep disturbance studies.

In the present study, the experiments on noise-induced sleep disturbance were performed in the participants’ homes. During the experiments, the participants were exposed to road traffic noise (single noise source) and road traffic in combination with construction or movie noise (combined noise sources). The effect of noise on sleep was evaluated by questionnaire, including questions on sleeping behavior, premature awakening, and subjective responses.

Section snippets

Stimuli

Road traffic noises, with small variations in noise level, were recorded alongside a road approximately 40 m in width using a binaural microphone (B&K, Type 4101). The average vehicle speed on this road was 60 km/h, and the percentage of heavy vehicles was around 20%. The construction noises were also recorded in a construction field including breakers and excavators, which are widely used for road repair work at night. For simulating noise from neighboring houses, 5-min of sounds were extracted

Effects of noise on sleeping behavior

Fig. 2 shows the effects of noise on sleeping behavior. It was found that about 90% of participants fell asleep listening to road traffic noise of 35 dBA, while others could sleep after switching off the noise, and could not fall asleep even after switching off the noise. When the participants were exposed to road traffic noise (T) combined with movie noise (M) or construction noise (C), expressed below as T + M and T + C for the sake of convenience, the numbers of participants who fell asleep in an

Relationships between sleeping behavior and subjective responses

In order to investigate the relationships between sleeping behavior and the subjective responses, the participants were classified into three groups according to the sleeping behaviors during each noise exposure; (1) Group A, who fell asleep listening to the noise in 1 h, (2) Group B, who could sleep after switching off the noise, and (3) Group C, who could not sleep even after stopping the noise. Three one-way ANOVAs were performed on sleep quality, sleep disturbance, and annoyance. The

Conclusions

In this study, experiments were carried out to investigate the effects of different types of noise exposure on sleep. The experimental results showed that road traffic noise in combination with construction noise may have a greater effect on sleeping behavior and premature awakening than combined noise sources, including movie noise. However, there was little effect of the type of combined noise sources on subjective responses such as sleep quality, sleep disturbance, annoyance, and

Acknowledgments

This work was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund, KRF-2007-313-D00451).

Cited by (0)

View full text