Night noise guidelines for Europe - WHO/Europe - World Health ...

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EXECUTIVE SUMMARY
An example of a health effect with limited evidence is myocardial infarction.
Although evidence for increased risk of myocardial infarction related to L day is sufficient
according to an updated meta-analysis, the evidence in relation to L night,outside
was considered limited. This is because L night,outside is a relatively new exposure indicator,
and few field studies have focused on night noise when considering cardiovascular
outcomes. Nevertheless, there is evidence from animal and human studies supporting
a hypothesis that night noise exposure might be more strongly associated
with cardiovascular effects than daytime exposure, highlighting the need for future
epidemiological studies on this topic.
The review of available evidence leads to the following conclusions.
• Sleep is a biological necessity and disturbed sleep is associated with a number of
adverse impacts on health.
• There is sufficient evidence for biological effects of noise during sleep: increase in
heart rate, arousals, sleep stage changes and awakening.
• There is sufficient evidence that night noise exposure causes self-reported sleep disturbance,
increase in medicine use, increase in body movements and (environmental)
insomnia.
• While noise-induced sleep disturbance is viewed as a health problem in itself (environmental
insomnia), it also leads to further consequences for health and wellbeing.
• There is limited evidence that disturbed sleep causes fatigue, accidents and reduced
performance.
• There is limited evidence that noise at night causes hormone level changes and clinical
conditions such as cardiovascular illness, depression and other mental illness.
It should be stressed that a plausible biological model is available with sufficient
evidence for the elements of the causal chain.
VULNERABLE GROUPS
Children have a higher awakening threshold than adults and therefore are often seen
to be less sensitive to night noise. For other effects, however, children seem to be
equally or more reactive than adults. As children also spend more time in bed they
are exposed more to night noise levels. For these reasons children are considered a
risk group.
Since with age the sleep structure becomes more fragmented, elderly people are more
vulnerable to disturbance. This also happens in pregnant women and people with ill
health, so they too are a group at risk.
Finally, shift workers are at risk because their sleep structure is under stress due to
the adaptations of their circadian rhythm.