Noise is one of the major environmental hazards of the modern world, originating from a wide variety of sources, including traffic (air, road, or rail), industrial facilities, or social activities. About 40% of the population in the European Union are exposed to road traffic noise with an equivalent sound pressure level (Leq) exceeding 55 dB(A) at daytime, whereas 20% are exposed to levels above 65 dB(A). Noise pollution is a major public health problem in developing countries as well. It is caused mainly by road traffic; the 24-hour Leq can reach even 75-80 dB(A) along the main roads. More than 30% of Europeans are exposed to Leq exceeding 55 dB(A) at night, which may cause sleep disturbances (1). Systematic noise measurements in Serbia were performed in four cities with a population over 250 000. The results of follow-up measurements in Belgrade over 30 years showed that outdoor noise levels exceeded the allowed limits on 23 out of 27 measuring sites for 11-16 dB during day and 10-14 dB during night (2).

In contrast to some other environmental problems, noise pollution continues to increase, followed by an increasing number of complaints from the exposed residents. The adverse health effects of community noise pose a serious public health problem. They include hearing impairment, interference with speech communication, disturbance of rest and sleep, psychological and performance effects, effects on one’s behavior, and subjective annoyance and interference with intended activities. Furthermore, noise has socio-cultural, esthetic, and economic effects. The estimated social costs for all noise nuisances are around 2.1% of the gross national product in industrialized countries, with about 0.2% attributable to productivity losses and 1.9% to decreases in property values (3).

Healthy sleep is a prerequisite for good physiological and mental functioning. However, disturbed sleep includes biological responses that may have numerous adverse effects on health and well-being, from difficulties with falling asleep, alterations of sleep stages, and awakenings to increased blood pressure and cardiac arrhythmia (4). The pathophysiological basis for a noise-sleep relation may be the stimulation of hypothalamus-pituitary-adrenal axis, adrenal medulla, and sympathetic nervous system with a subsequent release of “stress hormones,” ie, adrenaline, noradrenaline, and cortisone (5). These biological responses might have long-term health implications including chronic fatigue syndrome, lower work productivity, increased proneness to accidents, and disturbances of blood pressure and coronary circulation.

Substantial individual differences in neuroendocrine, immune, and behavioral responses to noise indicate that the level of noise itself may not be of primary importance. A close relation between arousal level and personality traits, such as introversion, neuroticism, and subjective noise sensitivity, can explain these differences (6,7). However, it is still unclear how important these personality characteristics are for the occurrence of sleep disturbances.

The aim of this study was to explore the relationship between extroversion-introversion, neuroticism, and subjective noise sensitivity as personality traits and sleep disturbances caused by traffic noise. We expected personalities characterized by higher levels of introversion, neuroticism, and subjective noise sensitivity to be more prone to noise-disturbed sleep.

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Road traffic noise and sleep disturbances in an urban population: cross–sectional study

In this paper, an attempt has been made to develop a fuzzy expert system for predicting the effects of sleep disturbance by noise on humans as a function of noise level, age, and duration of its occurrence. The modelling technique is based on the concept of fuzzy logic, which offers a convenient way of representing the relationships between the inputs and outputs of a system in the form of IF-THEN rules. It has been established on the basis of findings of various researchers that the effect of noise on sleep disturbance depends to a large extent on age. The middle-aged people have more probability of sleep disruption than the young people at the same noise levels. However, very little difference is found in sleep disturbance due to noise between young and old people. In addition, the duration of occurrence of noise is an important factor in determining the sleep disturbance over the limited range from few seconds to few minutes. Finally, we have compared our model results with some of the findings of researchers reported in International Journals.

A fuzzy expert system for noise-induced sleep disturbance

Deleterious effects of an environmental noise on sleep and contribution of its physical components in a rat model.

Factors modifying the effect of environmental noise on sleep include sex, age, susceptibility, personality and the health status, including past and present history of disease. Objective: The effects of noise on sleep and habituation of sleep to noise were summarized. Results and conclusions: 1) The effect of noise on sleep is associated with physical changes, such as changes in heart rate, blood flow volume, breathing and the immune and neurocirculatory systems. During sleep, specific changes in these indicators are noted during different sleep stages. There are individual and sex differences, and it is important to understand the effects of noise on sleep considering several related factors. 2) Habituation to noise is also an important phenomenon that must be addressed while considering the effects of noise on sleep. Habituation is dependent on the type and sound level of the noise. In occupational fields, shift work and job stress should be considered to determine the association between noise and sleep, which is important to retaining a good quality of working life.

http://joh.sanei.or.jp/pdf/E53/E53_6_01.pdf

Noise and health--sleep disturbance in adults.

Question of the study
This study tested the assumption that rail noise impaires sleep, subjective sleep quality, and performance

Railway noise-its effects on sleep, mood, subjective sleep quality, and performance

The disturbance of sleep by traffic noise is a major problem area in noise pollution. Extensive laboratory tests using multichannel electroencephalograms (EEG) have been carried out by many workers to determine the general response of people when exposed to noise during sleep. An experimental technique for obtaining results in people’s homes has been developed using a simplified one‐channel EEG. The responses of six people in the age range 19–24 were measured. A significant correlation was found between sleep disturbance and traffic noise when the noise is expressed in EPNdB. In the home experiments the subjects appeared to be approximately 10 dB less sensitive to noises than laboratory subjects for similar noise exposure. There also appeared to be some adaptation to the noise exposure; however, only one subject was tested for a period of 20 days and was insufficient to give definite results on adaptation.

N. R. McKellar

Papers

The effect of traffic noise on sleep of young adults in their homes