Like other types of pollution, exposure to noise can have major consequences for human health. Though many people assume they just get accustomed to it, recurrent exposure to excessive sound levels — especially at low frequencies — can cause a variety of adverse long-term health effects.1
Evolution programmed the human body to respond to noise as a warning of a potential threats, and the multitude of modern sources activates this natural ”flight or fight” response. Numerous scientific studies have documented how exposure to noise triggers the release of stress hormones such as adrenaline and cortisol, which can raise people’s heart rates and blood pressure, even while they are asleep.
For this reason, noise pollution is a significant public health issue with a range of adverse effects, including:
Sleep disruption — Noise can have immediate effects on sleep such as waking people up or altering their sleep stage, lingering effects the next day such as issues with cognitive functioning and productivity, and long-term effects such as chronic sleep problems and impaired immune systems.
The World Health Organization (WHO) reports that night-time noise ”may reduce the restorative power of sleep” and that sleep fragmentation can impact motor performance and even creativity, among other things. Noise can cause stress even when a person is sleeping.
Cardiovascular disease — Evidence links ambient noise, and loud traffic in particular, to various cardiovascular effects including high blood pressure, hypertension, heart disease, and stroke. Some studies further suggest that night-time noise has an especially large impact, as the awakening response triggered by noisy environments takes a physiological toll over time.
Cognitive impairment — An alarming amount of evidence connects noise with impaired cognitive development in children, whose developing brains are more susceptible to its disruptive effects. Pervasive background noise may damage the hearing center of babies’ developing brains, research has found, possibly leading to auditory and language-related development delays.1
Repeated exposure to noise during critical periods of development may affect a child’s acquisition of speech and language, reading and listening skills, and problem-solving and memory. Children in classrooms buffeted by outside noise lag behind, and their teachers report lower job satisfaction.
One compelling study cited by the WHO found a link between noise exposure and deficits in memory and reading comprehension, which went away when the exposure ceased. For this reason, reducing noise levels around schools is a key focus for public policy.
Anxiety / stress — The World Health Organization notes that being startled by or annoyed at noise can itself have ”an adverse effect on health” and lead to a host of stress-related symptoms such as high-blood pressure, fatigue, depression, and stomach ailments.
Permanent hearing damage — Noise-induced hearing loss (NIHL) is the most obvious and directly correlated effect of extended exposure to excessive noise, but research also points to it as a potential cause of tinnitus, a condition in which people hear a persistent hissing or ringing sound being generated from within their ears (also described by the WHO as ”the inability to perceive silence”).
Among other reported adverse health effects of excessive noise are Type 2 diabetes, low birth-weight in babies, aggravating dementia in older adults, and even affecting patient outcomes and staff performance in hospitals.
And conversely, studies show that reducing noise levels can help lower blood pressure, facilitate the development of new brain cells, decrease stress levels, and prevent plaque formation in arteries (i.e., arterialsclerosis).
Download our Health Effects of Noise infosheet (English / Spanish)
”[I]n every country, people’s health could be improved by reducing
environmental risks including pollution, hazards in the workplace,
[sun exposure], noise, … and climate and ecosystem change.”
— World Health Organization, 2007