Can noise cause true health problems?
In the occupational environment, the health effects of noise are quite clear. Hearing loss is common in those professions where workers are continuously exposed to noise levels of 85 decibels or higher. Individual sensitivity is quite variable, however. Hearing loss can also be a result of listening too loud music.
Jared Diamond tells in his book “Collapse” about a small Pacific island state Tikopia whose inhabitants could not comprehend that there could be a country where the sound of the waves would be not heard. The forest is not a quiet place either; the noise level is quite high and persistent, especially if it is windy. Thus human history is not a history of peace and quiet.
In our present society, one has to keep asking, however, what are the adverse effects of the present noise levels on health, and in particular the roar of traffic. These could include disturbance of sleep, stress on the cardiovascular system, and possible effects on behaviour and working capacity.
Some sleep disturbances are detected if there is a continuous noise level exceeding 30 to 40 dB. Noise peaks disturb sleep, and peaks of 45 dB or higher are unfavourable. Noise not only will waken you, it will cause changes in sleep quality, heart rate, and the rate of respiration and the after-effects of a poor night’s sleep may be fatigue, decreased performance, and labile mood. The association of prolonged sleep disturbances with illnesses is a still-to-be-resolved question though it is likely that there are huge inter-individual differences in sensitivities to sleep disruption.
Well-being and nuisance
Noise obviously is an important factor in determining well-being. Along with other environmental factors, it is an impediment to learning and causes communication problems. An increased risk of accidents has also been associated with noise-related distractions. Furthermore, noise makes people irritable and an annoyed person may behave in an unpredictable way. In particular, the noise created by human activities is crucial e.g. in schools and in the workplace.
Noise is a very personal and subjective matter; noise disturbing to one individual may be reassuring to somebody else. One typical irritant for some people is the thump-thump rhythm of the bass, especially in public places. To others, this sound may be reassuring reminding him or her of the peace of the womb, listening to the mother’s heartbeats. However, the decibels of bass rhythm emitted by some car stereo systems make you wonder about the state of the ears and the hearing ability of the driver.
In fact, hearing tests of Finnish army conscripts have revealed that the hearing threshold of young men has gradually worsened during the last twenty years. Quite many of them also are suffering from tinnitus or other auditory symptoms with the most likely reason being leisure time noise.
A certain percentage of people consider themselves to be noise sensitive. There is recent data that this is partially an inherited characteristic, but does it cause anything else than perhaps irritation? In epidemiological studies, hypertension does seem to be more common among noise sensitive persons, and there even seems to be an association to elevated death rate from heart diseases in those individuals.
A high noise level is an indisputable health concern, and causes hearing loss. Lower noise levels cause sleep disturbance and are more of a nuisance factor though they can influence both performance and mood. The contribution of noise to chronic diseases such as cardiovascular diseases is still an open and ambiguous question, but scientists are taking this possibility seriously.
Notes and references
- Decibel (dB) is a logarithmic unit of sound level meaning that the sound intensity is tenfold after each increase of ten units. Thus the difference between 40 decibels and 80 decibels is ten thousand-fold (104).
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