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Last changed: 13/03/2008
Sound is ever-present in all our lives. It is a significant feature of our social lives, albeit one that is often undesired at the same time. We are biologically engineered to generate sound and to process it. We need sound for the purposes of communication and orientation, and it can serve as a warning signal. For these reasons we are equipped with a very fine sensor which is capable of perceiving sound. This sensor is the ear along with the various levels of processing which follow on in the brain. The sensor is constantly active, even during sleep. Sound turns into noise, however, if given rise to exposure, nuisance, adverse effects, or physical damage.
Excessive sound – whether in terms of intensity or duration – can lead to sustained deleterious health effects or permanent damage. These can be to the ear, which can be permanently damaged by short-lived sound peaks or ongoing sound (aural effects). This category includes adverse effects on the hearing, through to clinical deafness, as well as short- or long-term ringing in the ears (tinnitus). High levels of noise are found not only in work environments, but also in leisure activities, e.g. in the form of loud music.
Furthermore, sound or noise has an effect on the whole organism, through the generation of stress reactions (extra-aural effects). These can also arise through exposure to lower intensity, non-ear-damaging noise levels found in the environment, such as road traffic noise.
Noise as a psycho-social stress factor thereby does not only vitiate subjective wellbeing and quality of life through the disturbance and distress it generates. But noise also impacts negatively on health in a narrower sense. It activates the sympathetic nervous and hormonal systems. Amongst the consequences are changes in blood pressure, heart rate, and other circulatory factors. The body generates increased levels of stress hormone, which in their turn affect the metabolic functions. Circulation and metabolism are mostly regulated by the sympathetic nervous system without conscious intervention. The autonomous reactions which occur therefore also arise in sleep and in people who consider themselves to be inured to noise.
Possible long-term consequences of chronic noise exposure include, in addition to hearing damage, other changes in respect of biological risk factors (e.g. blood fat, blood sugar, clotting factors) and circulatory disease such as arteriosclerotic changes (“arterial calcification”), high blood pressure, and certain heart diseases including myocardial infarction.
The German Federal Environment Agency (Umweltbundesamt – UBA) is conducting laboratory experiments and epidemiological studies on these subjects, in order to assess the quantitative impact of acoustic environmental factors on health, and to derive noise quality targets from this for the environment and leisure sectors. This objective is being pursued both nationally, and at European and international levels. Traffic-related sources of noise such as road, air, and rail traffic, and leisure-related noise such as loud music from discotheques, concerts, and headphones, and loud children’s toys, form the particular focus of these studies. The Federal Environment Agency is taking pains to improve the protection of the population from adverse noise effects by means of its scientific and political consultation activities.