Noise Pollution: Harmful Impact On Health And Wellbeing

Noise pollution is any unwanted, disturbing, or excessive sound that can have a range of negative impacts on human health. Sources of noise pollution include transportation, roadworks, and entertainment systems, with cars, trains, and airplanes being some of the worst offenders. The effects of noise pollution on health can be both physical and mental and range from mild conditions like sleep disturbances and stress to more severe issues like cardiovascular disease and hearing loss. With growing urbanization, understanding and mitigating the impact of noise pollution on human health is becoming increasingly important.

Cardiovascular health

Noise pollution has been linked to a range of cardiovascular issues, including hypertension, myocardial infarction, and stroke. Noise, defined as unwanted sound, can cause sleep disturbances, anger, and trigger conditions such as tinnitus and coronary heart disease caused by reduced blood flow to the organ.

Noise can cause annoyance and disturb sleep, and it can impair cognitive performance. Evidence from epidemiological studies demonstrates that environmental noise is associated with an increased incidence of arterial hypertension, myocardial infarction, and stroke. Both observational and experimental studies indicate that nighttime noise, in particular, can cause disruptions of sleep structure, increases in blood pressure and heart rate, and increases in stress hormone levels and oxidative stress, which, in turn, may result in endothelial dysfunction and arterial hypertension.

The Nobel Prize winner Robert Koch predicted in 1910 that "one day man will have to fight noise as fiercely as cholera and pest". Indeed, noise has been shown to interfere with communication, disturb sleep, and cause annoyance. Long-term exposure to relevant noise levels has been linked to negative health outcomes, including an impact on cardiovascular and autonomic homeostasis.

Noise exposure modifies the function of multiple organs and systems. Acute noise exposure can cause increases in blood pressure, heart rate, and cardiac output, likely mediated by the release of stress hormones such as catecholamines. The activation of the sympathetic nervous system and increased excretion of stress hormones such as cortisol, adrenaline, and noradrenaline can lead to the development of oxidative stress and inflammatory processes, resulting in disruption of vascular and endothelial function.

Chronic exposure to noise has been associated with an increased risk of hypertension, with a meta-analysis of 24 cross-sectional studies reporting an odds ratio of 1.07 per 10-decibel increase in daytime average road traffic noise level. Another meta-analysis of 12 studies reported an odds ratio of 1.08 per 10-decibel increase in weighted day-night noise level.

Noise-induced stress can lead to changes in blood lipid and glucose metabolism, as well as increased blood viscosity and activation of blood coagulation, all of which contribute to an increased risk of cardiovascular disease. Additionally, noise-related development of further risk factors such as elevated blood pressure, increases in blood lipids and blood sugar, increased cardiac output, and raised blood viscosity can further increase the risk of cardiovascular disease.

Overall, noise pollution, particularly from transportation sources, has been linked to a range of cardiovascular issues, with chronic exposure to noise starting at 50 decibels associated with negative cardiovascular effects. The risk of cardiovascular disease increases with increasing noise levels, and noise pollution has been identified as an important risk factor for cardiovascular illness.

Sleep disturbance

Noise pollution can cause difficulty falling asleep and remaining asleep. It can also reduce the depth and quality of sleep, altering the amount of rapid eye movement (REM) sleep. This can have a knock-on effect on a person's mood and ability to concentrate the next day. Poor sleep is also bad for heart health and can cause tiredness, depressed moods, poor performance at many tasks, and reduced reaction times.

Research has shown that people living near airports or busy roads take more sleeping pills and sedatives, are more prone to minor accidents, and are more likely to seek psychiatric treatment. Even if the noise doesn't wake someone up, it appears that continual noise sets off the body's acute stress response, which raises blood pressure and heart rate, potentially mobilising a state of hyperarousal. This response can lead to cardiovascular disease and other health issues.

A study by Dr Orfeu Buxton, a sleep expert at Harvard University, monitored the brain activity of healthy volunteers while they slept. The volunteers were played 10-second sound clips of different types of noise. The brainwaves of the participants spiked in jagged, wake-like patterns of neural activity when each clip was played.

When indoor noise levels are reduced, REM sleep and deeper, slow-wave sleep can increase. However, greater levels of noise pollution increase the number of night awakenings and changes between sleep stages.

Hearing damage

Noise pollution can cause hearing damage, also known as noise-induced hearing loss (NIHL). NIHL can be caused by a one-time exposure to an intense "impulse" sound, such as an explosion, or by continuous exposure to loud sounds over an extended period.

The human ear changes sound waves into electrical signals, which are then carried to the brain by the auditory nerve. The cochlea, a snail-shaped structure in the inner ear, is lined with sensory hair cells. On top of each hair cell is a bundle of stereocilia, which sways with sound vibrations. Over time, sounds that are too loud can damage these hair cell bundles. When that happens, hair cells can’t send information about sounds to the brain. In humans, the hair cell bundles cannot be fixed or replaced, so this damage leads to permanent hearing loss.

The louder the noise, the faster it can damage your hearing. If the noise is very loud, you could lose your ability to hear instantly. If the noise is not as loud but long-lasting, hearing damage can build slowly. NIHL can happen to anyone at any age, so it’s important to protect your hearing and that of your children.

There are three key factors that affect whether and how much a sound will damage your hearing: decibel level, distance, and time. The higher the decibel level, the louder the noise. The closer you are to the source of the sound, the more likely it is to damage your hearing. The longer you are exposed to the sound, the more harmful it is.

Sounds at or below 70 decibels (dBA) are unlikely to cause hearing loss, even after long exposure. However, long or repeated exposure to sounds at or above 85 dBA can cause hearing loss. The louder the sound, the shorter the amount of time it takes for NIHL to occur. For example, you can listen to sounds at 85 dBA for up to 8 hours, but if the sound increases to 88 dBA, it is only safe to listen for 4 hours, and if it increases to 91 dBA, safe listening time decreases to 2 hours.

Recreational activities that can put you at risk of NIHL include target shooting and hunting, snowmobile riding, listening to music at high volume through earbuds or headphones, playing in a band, and attending loud concerts. Harmful noises at home may come from sources such as lawnmowers, leaf blowers, and woodworking tools.

Stress and anxiety

Noise pollution can have a significant impact on a person's mental health, particularly in triggering and exacerbating stress and anxiety. The brain is always monitoring sounds for signs of danger, even during sleep. As a result, frequent or loud noise can trigger anxiety or stress. Continued exposure to noise pollution increases a person's sensitivity to stress, and they may feel irritable, on edge, frustrated, or angry. If a person feels they cannot control the amount of noise in their environment, its impact on their mental health intensifies.

Noise pollution is particularly harmful to those vulnerable to mental illnesses, as it can increase the development and symptoms of disorders. It can also contribute to nervousness, anxiety, emotional instability, moodiness, and argumentativeness, causing social conflicts.

Noise pollution can also cause sleep disturbances, which in turn can affect a person's mood and ability to concentrate. A person may experience difficulty falling asleep and an inability to stay asleep. Sounds can also reduce the depth and quality of sleep, altering the amount of rapid eye movement sleep. This can impact a person's mood and ability to concentrate.

Research has shown that people living near airports or busy roads have a higher incidence of headaches, take more sleeping pills and sedatives, are more prone to minor accidents, and are more likely to seek psychiatric treatment.

The impact of noise pollution on mental health is an underreported factor, and many people are experiencing a rise in noise pollution due to an increase in human activity.

Concentration and memory

Noise pollution can have a significant impact on a person's concentration and memory. Unwanted or loud noise can make it challenging for people to focus, leading to reduced productivity and poor performance over time. This is especially true for children, who may experience communication and speech development issues, as well as cognitive performance difficulties. Noise pollution can also affect a child's behaviour, their ability to form relationships, and their confidence.

Research has shown that people living near airports or busy roads have a higher incidence of headaches, increased use of sleeping pills and sedatives, and are more prone to minor accidents. They are also more likely to seek psychiatric treatment.

The human ear is extremely sensitive and never rests, even during sleep. As a result, background noises such as traffic, aircraft, or music are still being processed, and the body reacts to them in different ways via nerves and hormones.

Noise pollution can trigger the body's acute stress response, which raises blood pressure and heart rate, and can lead to cardiovascular disease and other health issues. This response can also cause fatigue, impair memory and creativity, impair judgement, and weaken psychomotor skills.

The impact of noise on concentration and memory is so significant that our ears need more than 16 hours of rest to recover from just two hours of exposure to 100 dB of noise.

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