Low frequency noise, the frequency range from about 10Hz to 200Hz, has been recognised as a special environmental noise problem, particularly to sensitive people in their homes. Conventional methods of assessing annoyance, typically based on A-weighted equivalent level, are inadequate for low frequency noise and lead to incorrect decisions by regulatory authorities. There have been a large number of laboratory measurements of annoyance by low frequency noise, each with different spectra and levels, making comparisons difficult, but the main conclusions are that annoyance of low frequencies increases rapidly with level. Additionally the A-weighted level underestimates the effects of low frequency noises. There is a possibility of learned aversion to low frequency noise, leading to annoyance and stress which may receive unsympathetic treatment from regulatory authorities. In particular, problems of the Hum often remain unresolved. An approximate estimate is that about 2.5% of the population may have a low frequency threshold which is at least 12dB more sensitive than the average threshold, corresponding to nearly 1,000,000 persons in the 50-59 year old age group in the EU-15 countries. This is the group which generates many complaints. Low frequency noise specific criteria have been introduced in some countries, but do not deal adequately with fluctuations. Validation of the criteria has been for a limited range of noises and subjects.

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Tonic tensor tympani syndrome (TTTS) is an involuntary, anxiety-based condition where the reflex threshold for tensor tympani muscle activity is reduced, causing a frequent spasm. This can trigger aural symptoms from tympanic membrane tension, middle ear ventilation alterations and trigeminal nerve irritability. TTTS is considered to cause the distinctive symptoms of acoustic shock (AS), which can develop after exposure to an unexpected loud sound perceived as highly threatening. Hyperacusis is a dominant AS symptom. Aural pain/blockage without underlying pathology has been noted in tinnitus and hyperacusis patients, without wide acknowledgment. This multiclinic study investigated the prevalence of TTTS symptoms and AS in tinnitus and hyperacusis patients. This study included consecutive patients with tinnitus and/or hyperacusis seen in multiple clinics. Data collected: Symptoms consistent with TTTS (pain/numbness/burning in and around the ear; aural "blockage"; mild vertigo/nausea; "muffled" hearing; tympanic flutter; headache); onset or exacerbation from exposure to loud/intolerable sounds; tinnitus/hyperacusis severity. All patients were medically cleared of underlying pathology, which could cause these symptoms. 60.0% of the total sample (345 patients), 40.6% of tinnitus only patients, 81.1% of hyperacusis patients had ≥1 symptoms (P < 0.001). 68% of severe tinnitus patients, 91.3% of severe hyperacusis patients had ≥1 symptoms (P < 0.001). 19.7% (68/345) of patients in the total sample had AS. 83.8% of AS patients had hyperacusis, 41.2% of non-AS patients had hyperacusis (P < 0.001). The high prevalence of TTTS symptoms suggests they readily develop in tinnitus patients, more particularly with hyperacusis. Along with AS, they should be routinely investigated in history-taking.

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Noise immissions with predominant low frequency sound components may exert considerably disturbing effects in dwellings. This applies in particular to sounds which are excitated by transmission of structure-borne noise, and to low frequency sounds emitted by ventilators. Exposed persons usually declare such immissions as being "intolerable" even at very low A­weighted sound levels. If mechanical vibrations in the frequency range below 20 Hz (ground-borne vibrations) affect dwelling rooms, the annoying effects are perceived only by a small portion of exposed individuals as a physical effect. For the most part the immissions are observed as vibratory effects on the building and on objects inside the dwelling. The disturbing effects of vibration frequencies above 20 Hz (structure-borne sound) are determined by the airborne sound field generated inside a particular room and its given surface and extension.

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This review concentrates on the effects of low frequency noise (LFN) up to 100 Hz on selected physiological parameters, subjective complaints and performance. The results of laboratory experiments and field studies are discussed in relation to the thresholds of hearing, of vibrotactile sensation and of aural pain. The effects of LFN may be mediated trough different ways. Temporary or permanent hearing threshold shifts seem to be due to acoustic stimuli above the individual hearing threshold. However, non-aural physiological and psychological effects may be caused by levels of low frequency noise below the individual hearing threshold. The dynamic range between the thresholds of hearing and of aural pain diminishes with decreasing frequency. This should be taken into account by the setting of limits concerning the health risks. Sufficient safety margins are recommended. The use of a frequency weighting with an attenuation of the low frequencies (e.g. G-weighting) does not seem to be appropriate for the evaluation of the health risks caused by LFN up to 100 Hz. It may be proposed to measure third octave band spectra or narrow band spectra. A comparison with the known human responses caused by the measured levels and frequencies could help to evaluate the health risks. Some proposals for further investigations were given: (1) experimental methods to discover the ways mediating the effects of low frequency noise, (2) consideration of the individual hearing threshold or hearing threshold shift and of the vibrotactile threshold in the low frequency range to be able to judge the effects, (3) consideration of combined body vibration caused by airborne low frequency noise or by other sources, (4) modelling to analyse the transmission of the acoustic energy from the input into the body to the structures containing sensors, (5) consideration of probable risk groups like children or pregnant women.

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Traffic noise is the most important source of environmental annoyance. According to the Environmental Expert Council of Germany, severe annoyance persistent over prolonged periods of time is to be regarded as causing distress. Previously, extraaural noise effects were mostly assessed using a paradigm in which the sound level played the major role. On the basis of this paradigm the relatively low sound level of environmental noise was not considered to be a potential danger to health. In contrast to this numerous empirical results have shown long­term noise-induced health risks. Therefore a radical change of attitude - a change of paradigm - is necessary. For an immediate triggering of protective reactions (fight/flight or defeat reactions) the information conveyed by noise is very often more relevant than the sound level. It was shown recently that the first and fastest signal detection is mediated by a subcortical area - the amygdala. For this reason even during sleep the noise from aeroplanes or heavy goods vehicles may be categorised as danger signals and induce the release of stress hormones. In accordance with the noise stress hypothesis chronic stress hormone dysregulations as well as increases of established endogenous risk factors of ischaemic heart diseases have been observed under long-term environmental noise exposure. Therefore, an increased risk of myocardial infarction is to be expected. The results of individual studies on this subject in most cases do not reach statistical significance. However, according to the Environmental Expert Council, these studies show a consistent trend towards an increased cardiovascular risk if the daytime immission level exceeds 65 dB(A). Most of the previous studies on the extraaural effects of occupational noise have been invalidated by exposure misclassifications. In future studies on health effects of noise a correct exposure assessment is one of the most important preconditions.

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Noise-induced hearing loss (NIHL) still remains a problem in developed countries, despite reduced occupational noise exposure, strict standards for hearing protection and extensive public health awareness campaigns. Therefore NIHL continues to be the focus of noise research activities. This paper summarizes progress achieved recently in our knowledge of NIHL. It includes papers published between the years 2008-2011 (in English), which were identified by a literature search of accessible medical and other relevant databases. A substantial part of this research has been concerned with the risk of NIHL in the entertainment sector, particularly in professional, orchestral musicians. There are also constant concerns regarding noise exposure and hearing risk in "hard to control" occupations, such as farming and construction work. Although occupational noise has decreased since the early 1980s, the number of young people subject to social noise exposure has tripled. If the exposure limits from the Noise at Work Regulations are applied, discotheque music, rock concerts, as well as music from personal music players are associated with the risk of hearing loss in teenagers and young adults. Several recent research studies have increased the understanding of the pathomechanisms of acoustic trauma, the genetics of NIHL, as well as possible dietary and pharmacologic otoprotection in acoustic trauma. The results of these studies are very promising and offer grounds to expect that targeted therapies might help prevent the loss of sensory hair cells and protect the hearing of noise-exposed individuals. These studies emphasize the need to launch an improved noise exposure policy for hearing protection along with developing more efficient norms of NIHL risk assessment.

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This paper presents a review of research carried out in the past 40 years into various aspects of noise in open plan classrooms. The emergence of open plan classroom design in response to progressive educational reforms is discussed. A limited amount of evidence of the effects of noise in open plan classrooms is presented. Surveys of both background and intrusive noise levels in open plan classrooms are summarized and compared. Differences between noise levels in open plan and enclosed classrooms are also considered. Recommended noise limits and acoustic design criteria for open plan classrooms are discussed, together with some current international standards. The paper concludes with a discussion of appropriate noise control measures to reduce noise and maximize speech intelligibility and speech privacy in open plan classrooms.

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Industrial wind turbines (IWTs) are a new source of noise in previously quiet rural environments. Environmental noise is a public health concern, of which sleep disruption is a major factor. To compare sleep and general health outcomes between participants living close to IWTs and those living further away from them, participants living between 375 and 1400 m (n = 38) and 3.3 and 6.6 km (n = 41) from IWTs were enrolled in a stratified cross-sectional study involving two rural sites. Validated questionnaires were used to collect information on sleep quality (Pittsburgh Sleep Quality Index - PSQI), daytime sleepiness (Epworth Sleepiness Score - ESS), and general health (SF36v2), together with psychiatric disorders, attitude, and demographics. Descriptive and multivariate analyses were performed to investigate the effect of the main exposure variable of interest (distance to the nearest IWT) on various health outcome measures. Participants living within 1.4 km of an IWT had worse sleep, were sleepier during the day, and had worse SF36 Mental Component Scores compared to those living further than 1.4 km away. Significant dose-response relationships between PSQI, ESS, SF36 Mental Component Score, and log-distance to the nearest IWT were identified after controlling for gender, age, and household clustering. The adverse event reports of sleep disturbance and ill health by those living close to IWTs are supported.

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The contradictory and confusing results in noise research on humans may partly be due to individual differences between the subjects participating in different studies. This review is based on a twelve year research on the role of neuroticism, extroversion and subjective noise sensitivity during mental work in noisy environment. Neurotic persons might show enhanced "arousability" i.e. their arousal level increases more in stress. Additional unfavorable factors for neurotics are worrying and anxiety, which might prevent them coping successfully with noise, or some other stressors during mental performance. In numerous experiments introverts have showed higher sensitivity to noise during mental performance compared to extroverts, while extroverts often cope with a boring task even by requesting short periods of noise during performance. Correlation analyses have regularly revealed a highly significant negative relation between extroversion and noise annoyance during mental processing. Numerous studies have shown that people with high noise sensitivity may be prevented from achieving the same work results as other people in noisy environment, thus leading to psycho­somatic, neurotic or other difficulties. Positive relation between noise annoyance and subjective noise sensitivity might be very strong. Our results have shown, after matching with the results of other relevant studies, that more stable personality, with extroversive tendencies and with a relatively lower subjective noise sensitivity measured with standard questionnaires, may be expected to better adapt to noise during mental performance, compared to people with opposite personality traits.

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The human perception of sound at frequencies below 200 Hz is reviewed. Knowledge about our perception of this frequency range is important, since much of the sound we are exposed to in our everyday environment contains significant energy in this range. Sound at 20-200 Hz is called low-frequency sound, while for sound below 20 Hz the term infrasound is used. The hearing becomes gradually less sensitive for decreasing frequency, but despite the general understanding that infrasound is inaudible, humans can perceive infrasound, if the level is sufficiently high. The ear is the primary organ for sensing infrasound, but at levels somewhat above the hearing threshold it is possible to feel vibrations in various parts of the body. The threshold of hearing is standardized for frequencies down to 20 Hz, but there is a reasonably good agreement between investigations below this frequency. It is not only the sensitivity but also the perceived character of a sound that changes with decreasing frequency. Pure tones become gradually less continuous, the tonal sensation ceases around 20 Hz, and below 10 Hz it is possible to perceive the single cycles of the sound. A sensation of pressure at the eardrums also occurs. The dynamic range of the auditory system decreases with decreasing frequency. This compression can be seen in the equal-loudness-level contours, and it implies that a slight increase in level can change the perceived loudness from barely audible to loud. Combined with the natural spread in thresholds, it may have the effect that a sound, which is inaudible to some people, may be loud to others. Some investigations give evidence of persons with an extraordinary sensitivity in the low and infrasonic frequency range, but further research is needed in order to confirm and explain this phenomenon.

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In several recent investigations it could be demonstrated that the free cortisol response to awakening can serve as an useful index of the adrenocortical activity. When measured with strict reference to the time of awakening the assessment of this endocrine response is able to uncover subtle changes in hypothalamus-pituitary-adrenal (HPA) axis activity, which are, for instance, related to persisting pain, burnout and chronic stress. Furthermore, it has been suggested that the HPA axis might serve as an indicator of allostatic load in subjects exposed to prolonged environmental noise. In the present paper four separate studies with a total of 509 adult subjects were combined in order to provide reliable information on normal values for the free cortisol response to awakening. Corresponding with earlier findings, a mean cortisol increase of about 50% within the first 30 minutes after awakening was observed. The intraindividual stability over time was shown to be remarkably high with correlations up to r=.63 (for the area under the response curve). Furthermore, the cortisol rise after awakening is rather consistent, with responder rates of about 75%. Gender significantly influenced early morning free cortisol levels. Although women showed a virtually identical cortisol increase after awakening compared to men, a significantly delayed decrease was observed. Confirming and extending previous findings, the present study strongly suggests that neither age, nor the use of oral contraceptives, habitual smoking, time of awakening, sleep duration or using / not using an alarm clock have a considerable impact on free cortisol levels after awakening. The cortisol awakening response can be assessed under a wide variety of clinical and field settings, since it is non-invasive, inexpensive and easy-to-employ. The present data provide normal values and information on potential confounds which should facilitate investigations into the endocrine consequences of prolonged exposure to environmental noise.

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Many studies have examined the use of portable music players portable listening devices (PLDs) from various ethnic groups. Some findings suggest that there may be differences among ethnic groups that lead to louder or longer listening when using PLD devices. For example, some studies found that Hispanic PLD users listen at higher volume levels while other studies found that African American PLD users listen at higher volume levels. No investigator has explained the reasons for differences among ethnic groups in listening intensity. This paper will address the possible reasons for these differences and offer guidelines for the prevention of noise-induced hearing loss.

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Vibroacoustic disease (VAD) is a whole-body, systemic pathology, characterized by the abnormal proliferation of extra-cellular matrices, and caused by excessive exposure to low frequency noise (LFN). VAD has been observed in LFN-exposed professionals, such as, aircraft technicians, commercial and military pilots and cabin crewmembers, ship machinists, restaurant workers, and disk-jockeys. VAD has also been observed in several populations exposed to environmental LFN. This report summarizes what is known to date on VAD, LFN­induced pathology, and related issues. In 1987, the first autopsy of a deceased VAD patient was performed. The extent of LFN­induced damage was overwhelming, and the information obtained is, still today, guiding many of the associated and ongoing research projects. In 1992, LFN-exposed animal models began to be studied in order to gain a deeper knowledge of how tissues respond to this acoustic stressor. In both human and animal models, LFN exposure causes thickening of cardiovascular structures. Indeed, pericardial thickening with no inflammatory process, and in the absence of diastolic dysfunction, is the hallmark of VAD. Depressions, increased irritability and aggressiveness, a tendency for isolation, and decreased cognitive skills are all part of the clinical picture of VAD. LFN is a demonstrated genotoxic agent, inducing an increased frequency of sister chromatid exchanges in both human and animal models. The occurrence of malignancies among LFN-exposed humans, and of metaplastic and displastic appearances in LFN-exposed animals, clearly corroborates the mutagenic outcome of LFN exposure. The inadequacy of currently established legislation regarding noise assessments is a powerful hindrance to scientific advancement. VAD can never be fully recognized as an occupational and environmental pathology unless the agent of disease - LFN - is acknowledged and properly evaluated. The worldwide suffering of LFN-exposed individuals is staggering and it is unethical to maintain this status quo.

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We report a cross-sectional study comparing the health-related quality of life (HRQOL) of individuals residing in the proximity of a wind farm to those residing in a demographically matched area sufficiently displaced from wind turbines. The study employed a nonequivalent comparison group posttest-only design. Self-administered questionnaires, which included the brief version of the World Health Organization quality of life scale, were delivered to residents in two adjacent areas in semirural New Zealand. Participants were also asked to identify annoying noises, indicate their degree of noise sensitivity, and rate amenity. Statistically significant differences were noted in some HRQOL domain scores, with residents living within 2 km of a turbine installation reporting lower overall quality of life, physical quality of life, and environmental quality of life. Those exposed to turbine noise also reported significantly lower sleep quality, and rated their environment as less restful. Our data suggest that wind farm noise can negatively impact facets of HRQOL.

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This article reviews the literature on research conducted during the last two decades on traffic noise impacts in India. Road traffic noise studies in India are fewer and restricted only to the metropolitan areas. The studies over the years have also focused on the monitoring, recording, analysis, modeling, and to some extent mapping related themes. Negligible studies are observed in areas of physiological and sleep research exposure-effect context. Most impact studies have been associated with annoyance and attitudinal surveys only. Little scientific literature exists related to effects of traffic noise on human physiology in the Indian context. The findings of this review search and analysis observe that very little studies are available relating to traffic noise and health impacts. All of them are subjective response studies and only a small portion of them quantify the exposure-effect chain and model the noise index with annoyance. The review of papers showed that road traffic noise is a cause for annoyance to a variety of degree among the respondents. A generalization of impacts and meta-analysis was not possible due to variability of the study designs and outputs preferred.

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Environmental noise remains a complex and fragmented interplay between industrialization, population growth, technological developments, and the living environment. Next to the circulatory diseases and cancer, noise pollution has been cited as the third epidemic cause of psychological and physiological disorders internationally. A reliable and firm relationship between the cumulative health implications with the traffic annoyance and occupational noise has been established. This agenda has called for an integrated, coordinated, and participatory approach to the reliable protection of noise interference. Despite several fragmented policies, legislation and global efforts have been addressed; the noise pollution complaints have been traditionally neglected in developing countries, especially in Malaysia. This paper was undertaken to postulate an initial platform to address the dynamic pressures, gigantic challenges, and tremendous impacts of noise pollution scenario in Malaysia. The emphasis is speculated on the traffic interference and assessment of industrial and occupational noise. The fundamental importance of noise monitoring and modeling is proposed. Additionally, the confronting conservation program and control measure for noise pollution control are laconically elucidated.

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Low frequency noise (20-200 Hz) is emitted by numerous sources in the society. As low frequencies propagate with little attenuation through walls and windows, many people may be exposed to low frequency noise in their dwellings. Sleep disturbance, especially with regard to time to fall asleep and tiredness in the morning, are commonly reported in case studies on low frequency noise. However, the number of studies where sleep disturbance is investigated in relation to the low frequencies in the noise is limited. Based on findings from available epidemiological and experimental studies, the review gives indications that sleep disturbance due to low frequency noise warrants further concern.

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Since the 1940s, various attempts have been made to treat peripheral tinnitus by way of intratympanic injection. This administration procedure requires only low concentrations of medication, thanks to the highly targeted delivery to the site of action and comes with minimal systemic exposure. While different compounds have been tested for their effects on tinnitus by intratympanic injection, there has been no breakthrough so far. Accordingly, the clinical use of intratympanic tinnitus treatments has remained limited to date. A more widespread adoption of this approach will require the development of specific medications for peripheral tinnitus, as well as proof of safety and efficacy, which would be determined from randomized controlled clinical trials.

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Reaction (annoyance, dissatisfaction) to noise is itself an important health effect, as well as possibly contributing to other putative health effects of noise. Thus, factors such as noise sensitivity, which influence reaction, are of considerable importance. However, noise sensitivity is rarely clearly defined. This paper offers a formal definition of noise sensitivity, and reviews evidence relating to it. Noise sensitivity has been measured in various ways, but may be measured most directly by assessing reaction to many noise situations (other than those involving the noise source(s) which are the focus of the particular study). When noise sensitivity is measured in this way, factor analysis consistently reveals that noise sensitivity is not a unitary concept. Rather, two distinct factors appear: one related to loud noises (road traffic, lawn mower), and the other related to quieter noise situations which are nonetheless distracting (rustling papers at the movies, people talking while watching television). More research is needed to address the relationships between these factors, reaction and other health effects.

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The review provides an overview of epidemiological studies that were carried out in the field of community noise and cardiovascular risk. The studies and their characteristics are listed in the tables. Risk estimates derived from the individual studies are given for 5 dB(A) categories of the average A-weighted sound pressure level during the day. The noise sources considered in the studies are road and aircraft noise. The health endpoints are mean blood pressure, hypertension and ischaemic heart disease, including myocardial infarction. Study subjects are children and adults. The evidence of an association between transportation noise and cardiovascular risk has increased since the previous review published in Noise and Health in the year 2000.

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The biological effects of electromagnetic waves are widely studied, especially due to their harmful effects, such as radiation-induced cancer and to their application in diagnosis and therapy. However, the biological effects of sound, another physical agent to which we are frequently exposed have been considerably disregarded by the scientific community. Although a number of studies suggest that emotions evoked by music may be useful in medical care, alleviating stress and nociception in patients undergoing surgical procedures as well as in cancer and burned patients, little is known about the mechanisms by which these effects occur. It is generally accepted that the mechanosensory hair cells in the ear transduce the sound-induced mechanical vibrations into neural impulses, which are interpreted by the brain and evoke the emotional effects. In the last decade; however, several studies suggest that the response to music is even more complex. Moreover, recent evidence comes out that cell types other than auditory hair cells could response to audible sound. However, what is actually sensed by the hair cells, and possible by other cells in our organism, are physical differences in fluid pressure induced by the sound waves. Therefore, there is no reasonable impediment for any cell type of our body to respond to a pure sound or to music. Hence, the aim of the present study was to evaluate the response of a human breast cancer cell line, MCF7, to music. The results' obtained suggest that music can alter cellular morpho-functional parameters, such as cell size and granularity in cultured cells. Moreover, our results suggest for the 1 ^st time that music can directly interfere with hormone binding to their targets, suggesting that music or audible sounds could modulate physiological and pathophysiological processes.

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The effects of classroom noise and background speech on speech perception, measured by word-to-picture matching, and listening comprehension, measured by execution of oral instructions, were assessed in first- and third-grade children and adults in a classroom-like setting. For speech perception, in addition to noise, reverberation time (RT) was varied by conducting the experiment in two virtual classrooms with mean RT = 0.47 versus RT = 1.1 s. Children were more impaired than adults by background sounds in both speech perception and listening comprehension. Classroom noise evoked a reliable disruption in children΄s speech perception even under conditions of short reverberation. RT had no effect on speech perception in silence, but evoked a severe increase in the impairments due to background sounds in all age groups. For listening comprehension, impairments due to background sounds were found in the children, stronger for first- than for third-graders, whereas adults were unaffected. Compared to classroom noise, background speech had a smaller effect on speech perception, but a stronger effect on listening comprehension, remaining significant when speech perception was controlled. This indicates that background speech affects higher-order cognitive processes involved in children΄s comprehension. Children΄s ratings of the sound-induced disturbance were low overall and uncorrelated to the actual disruption, indicating that the children did not consciously realize the detrimental effects. The present results confirm earlier findings on the substantial impact of noise and reverberation on children΄s speech perception, and extend these to classroom-like environmental settings and listening demands closely resembling those faced by children at school.

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In recent years, the measurement of stress hormones including adrenaline, noradrenaline and cortisol has been widely used to study the possible increase in cardiovascular risk of noise exposed subjects. Since endocrine changes manifesting in physiological disorders come first in the chain of cause-effect for perceived noise stress, noise effects in stress hormones may therefore be detected in populations after relatively short periods of noise exposure. This makes stress hormones a useful stress indicator, but regarding a risk assessment, the interpretation of endocrine noise effects is often a qualitative one rather than a quantitative one. Stress hormones can be used in noise studies to study mechanisms of physiological reactions to noise and to identify vulnerable groups. A review is given about findings in stress hormones from laboratory, occupational and environmental studies.

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Anecdotally it has been suggested that exposure to some noise sources through leisure activities could have a significant effect on whole-of-life noise exposure. While exposure levels do vary, a typical night club or dance club attendee was found to experience an equivalent continuous A-weighted noise level of around 98 dB for up to 5 hours with an exposure of 12.2 Pa ² h. This can extend up to 104 Pa ² h in extreme cases. A study of "clubbers" reveals regular clubbing to be a source of high noise exposure, with a sustained period of regular club attendance contributing to a significant portion of whole-of-life noise exposure.

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