Health Effects Of Noise Pollution: Continuous Stress, Insomnia & More

I've got an important message: noise pollution can ruin your health over time.

Don't believe me?

Well, this blog post looks at the science of noise pollution and what it does to your health.

But let's take a step back:

Remember that in the previous blog post I wrote, I gave a definition of sound and noise and taught you the basics of how to understand them.

In this blog post, I'll look at some devastating potential consequences of noise, such as stress responses, blood sugar dysregulation, higher heart rates and increases in heart and blood vessel disease risk, inflammation, impaired brain function, and more.

I've divided this blog post into several sections - these sections are listed in the table of contents below:

 

Table Of Contents:

 

You can read these sections independently, although, for the best understanding, read them consecutively.

Ready to learn what noise does to your health? Start reading more below:

  

 

Recap Of The Previous Blog Post Explaining Sound And Noise

Many people only have a very basic understanding of sound and noise. In the previous blog post, I defined noise as: 

[I]f a sound either 1) reaches a certain loudness threshold; or 2) is disliked by you, that sound becomes noise. 

 Let's also recap what exactly sound is. Wikipedia defines sound as such:

"In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid."

Your ears pick up that sound, and next, your brain processes the vibrations as sound. If the sound is unpleasant or merely very loud then it becomes noise.

One very important tactic to control your noise exposure is to measure it. How? The decibel scale:

 

Measuring Sound With The dB Scale

What most people don't know sound levels exist on an extreme continuum. Such sound levels - indistinct or loud - are expressed on a decibel (dB) scale. 

The dB scale is logarithmic. In the case of the dB scale logarithmic means that a 10-fold increase on the scale leads to a 10-fold increase in loudness.

Maybe that dB scale is hard to imagine so let's begin with an example. Here's a list of different loudness levels according to my latest blog post where I define noise pollution:

10dB - Your breathing, the Grand Canyon at night, or the sound of dropping a pin
20dB - Leaves in the forest, whispering of a single person, a rural area with snow
30dB - A common quiet rural area sound level, or running computer.
40dB - Multiple people whispering in a classroom, library sound, birds singing
50dB - Regular conversations, very light traffic, background music, dishwasher
60dB - Air conditioner, bypassing car at 50 miles per hour, restaurant conversation

Now, at 65dB noise can already become damaging (if you're exposed for a long time):

70dB - Showering, music at regular-loudness, bypassing trucks, vacuum cleaner
80dB - Drilling machine, your morning alarm clock, a bypassing freight train
90dB - Low-flying Boeing 737, mp3 player, lawnmower
100dB - Subway car, food processor, airplane take-off, motorcycle
110dB - A rock concert, jackhammer, or an auto horn at a 3-yard distance
120dB - Classroom filled with screaming children, thunder impact
130dB - Football stadium noise peak

At this point, noise starts to generate ear-pain:

140dB - Jet engine take-off, firecrackers
150dB - Rock concert peak near speakers, fighter jet take-off
160dB - Weapons firing (such as a shotgun), 
180dB - Rocket launch
194dB - Official maximum sound level - at this point, a sound is converted into "shockwaves".

That list should give you a great basic understanding of different sound levels.

Let's make some calculations to make sure you understand:

 

Example Of Decibel (dB) Scale Calculation

Let's say I compare 2 different sound levels. One level is the sound of a computer running (30dB) while the other one is a restaurant conversation (60dB).

Notice that therés a 30dB difference between those two numbers. At first sight, many people would think that the restaurant conversation is 2 times as loud as the sound of the computer. However, a 30dB difference entails a difference of 10*10*10 or 1,000-fold difference.

In other words, the average restaurant conversation is thus 1,000-fold as loud as the sound of a computer running in the background.

The implication of that statement? Let's find out:

 

The Problem Of Noise Pollution

If you've closely looked at the dB chart I posted above, you've noticed that in nature, 30-40dB levels are very normal. 

In most modern locations, those 30-40dB levels are no longer present. In fact, during the daytime, modern cities have dB exposure levels of 60-90dB.

Let's take the difference between 40dB and 80dB, for instance. Again, that difference in loudness isn't a 2-fold difference but is 10*10*10*10 (or 10^4) = a 10,000-fold difference.

Implication?

There's tons of noise all around you in a modern city. Of course, you're not powerless by any means - I'll explain why in the third and last installment of this series.

Furthermore, even at night, many cities have sound levels of 50-70dB. For high-quality sleep, you'll want those numbers to be 35dB at the maximum. Fortunately, walls and windows do reduce the sound level dramatically.

But still, a third of people living in the European Union currently experience excess sound (and thus noise) at nighttime. In Asian countries, when high population densities are present, the problem is even worse.

Daytime noise exposure, additionally, can also be a problem. If you're working in an office, for instance, 60-80dB levels can exist on a daily basis. Working in such an environment for 40 hours a week will have health consequences as it physically drains you 24-7.

Why?

Let's explore some of the consequences of noise pollution now - the goal of this blog post in the next section. I'm glad you now understand that noise is present much more in society from the summary of my first blog post. So let's move on:

 

 

How Noise Pollution Causes Chronic Low-Level Of Stress In Your Body

Imagine:

Another overflying airplane again. 80dB of nightly irritation.

Let's find out what exactly occurs in your body when you're exposed to noise.

 

Stress Hormones

First of all, during the nighttime, being exposed to noise increases your stress hormone levels.[35; 36; 37; 38; 39; 40; 41; 42; 168; 260]

"Cortisol" and "adrenaline" are two commonly known stress hormones. High levels of noise can increase these stress hormones for several hours. If you're really sensitive to noise, a mere 40dB sound can already increase cortisol levels in your body.

That 40dB sound roughly equals whispering people, or birds singing. 

For most people who are less sensitive, I think the threshold lies somewhere between 50 and 70dB during the day.

But there's more to noise:

Noise levels that many would not consider that bad, such as 60db - the sound level of bypassing cars or a restaurant - can already change your (stress) hormone levels:

Even during the daytime, aircraft sound or road traffic will increase your cortisol levels.[32; 33; 34]

If you're exposed to more than 60dB due to aircraft noise, for instance, your overall cortisol levels will be 33% higher than people who are exposed to less than 50dB on a 24-hour basis.

The same is true if you're working in an industry with 80dB+ noise levels.

Let's consider the example of someone working in a noisy industry:

If cortisol is measured in the morning time, your cortisol levels will be roughly similar on a working day and an off day. If your cortisol levels are taken in the evening, however, after getting exposed to that loud 80dB noise long enough, your cortisol levels will be much higher than during your day off.

That's all?

No, sadly enough:

 

Increases In Resting Heart Rate

Every one-dB levels increase of the sound level raises your heart rate by 0,29 beats per minute (when studying a range between 50dB and 90dB noise levels)

A 10dB increase in background noise will thus increase your heart rate by 3 beats per minute. A 30dB increase in environmental sound - which is the difference between rural areas and inner cities, will thus increase your heart beats per minute by 10.

It takes just one minute for your heart rate to go up after an increase in sound exposure. Your heart thus works overtime with more noise exposure. 

 

Lowered Sleep Quality

Next, noise has big effects on your sleep quality:

While I'll treat the topic of sleep in more detail in the next section, let's consider what happens when you're woken by sound during the night:[26; 27; 28; 29; 30; 31; 32]

At 32dB, fortunately, you're not awoken by any environmental noise.[30]

At higher sound levels, however, you will be having negative sleep quality effects. A person who whispers at night in your room - at 40dB - is thus already loud enough to wake you up.

Noise during sleep affects many people. In the European Union, almost 600,000 people are experiencing negative effects of more than 55dB of noise during the night.

That 55dB sound level equals hearing a dishwasher or light traffic from a small distance. In other words, 600,000 people have to sleep at night while hearing a sound that's as loud as cars passing by.

One big problem of becoming awake during the night due to noise is that you'll not always remember those moments.[31] Noise can easily put you out of sleep for 15-45 seconds. When morning time arrives, you'll simply think that you've slept through the night - unless the noise was really loud and obvious.

In your body, however, real negative changes occur when you're woken up during the night.

There's more to noise though:

 

Oxidative Stress

Noise causes what is called "oxidative stress".[163; 271; 272]

Oxidative stress basically entails the creation of "Reactive Oxygen Species" (ROS) in your body. Some ROS is necessary for optimal health, but ROS levels that are too high can be damaging to your health.

(Oxidative stress means that a specific chemical reaction with oxygen increases in your cells.)

Noise can give you ROS levels that are too high because the ROS levels have not been created in a really natural way - such as temporary stress due to exercise. That oxidative stress, in turn, causes noise-induced hearing loss - a topic I'll come back to later. 

Next, noise influences your brain at several levels... 

 

Psychological And Biological Stress In Your Brain

Your brain has an "auditory system". That auditory system is connected to other brain areas.[252; 253; 254; 256; 257; 258; 259; 260]

Many brain areas actually participate in your hearing.

I'd like to talk about one very important area called the "amygdala". I've mentioned this brain area before in my blog post about stress.

That amygdala is an alarm bell in your brain. Noise in your environment can trigger that amygdala. As a result, your body releases stress hormones and activates your nervous system.

I've often talked about human beings evolving in Africa roughly 250,000 years ago. Our lifestyle back then was very different than how you're living in modern society.

Back then, your hearing system was naturally attuned to filtering out sounds that could affect your survival.[36; 37; 262; 263]

traditional societies experience low noise levelsTraditional societies: never experiencing
consistent 50>dB levels...

Example:

When you hear a snake nearby, even though its loudness only approximates 40dB, that sound triggers a "fight, flight or freeze" response in your body. Let's consider these three different fight, flight, or freeze options:

  1. You can fight the snake. Fighting snakes is usually not the best option, but you might not have an alternative if you're cornered. 
  2. You can flee from the snake. In most situations, this is a great option. because there's very little to win from fighting a snake.
  3. You can freeze in absolute fear and petrification. This is a "deer in the headlights" reaction, where the body actually inhibits the nervous system and prepares the body for its final demise. You'll probably have a freeze response if you anticipate the snake will attack you in the next 500 milliseconds (which equals half a second), and there's no way out...

From an evolutionary perspective, your body is naturally attuned to environmental sounds so that can accomplish its very survival. 

In modern society, however, sounds are almost everywhere - and have become noise. 

When there's lots of sound present, your brain has to process and filter all those sounds. 

 

Why Loud Sound Is Always Noise

Sounds which are really loud, at a 90dB rating, for example, are also inherently stressful. Even the sound of a loud lawnmower or lots of traffic--although many people do not associate that sound with stress--will automatically cause a small stress reaction in your body.

Noise can thus put your body in a "fight, flight, or freeze" response, by causing your amygdala to ring the alarm bells. That response occurs spontaneously and there's little you can do to prevent it, even though that stress is detrimental to your health in the long-run.

Are there examples of that response automatically being triggered?

Sure:

The sound of a dental drill, for instance, will automatically trigger a small stress response in many people. The same is true for hearing very hard laughter in the middle of the night, or the breaking of a window.

Almost everyone automatically responds to these sounds because we've been conditioned to interpret them as a form of danger. Loud noises are always interpreted as a form of danger by the brain.

But there's more to our human hearing:

 

The Relationship Between Human Hearing And Noise

Human ears are not only made to signal danger but also to find our prey. 

The fact that the human ear has such a wide ability to pick up different sounds between 0dB and 140dB - which is an obscene 100 trillion (100,000,000,000,000) fold difference - demonstrates that we're meant to be attuned to many types of sounds, and their loudness.

Your ears are thus adjusted to hearing both a fish swimming that's almost unnoticed underwater and the roaring of a lion.

One reason your ears are attuned to so many different sounds is because the different parts of the ear can magnify the intensity of sounds. The ear - fortunately for our modern society - also contains mechanisms to tone down sound again.

And if you ask: "why do we have two ears, then, and not one?", I will answer: because with just one ear, it's harder to pinpoint the location of any sound...

Just as two eyes give you a three-dimensional perspective qua vision, your ears do the same for hearing.

(Advanced explanation: the paragraphs listed above on how sound works in the brain are oversimplified. A few other brain areas involved in sound are:[264; 265; 266; 267; 268; 269; 270]

- the cochlear nucleus in the brainstem, which receives the first sound input from the inner ear, and is the gateway to the rest of the brain's "audio system"
- the olivary body and trapezoid bodies, which help with the localization of sounds and integrate sounds that originate from both ears into a whole.
- the inferior colliculi, interestingly enough, may filter out sounds that you make yourself from conscious awareness, such as from eating your food or breathing. These parts are connected to both the brainstem and auditory cortex. 
- the medial geniculate nucleus acts as a relay station between the auditory cortex and some of the aforementioned lower brain areas associated with sound. This area can modulate fear-producing sounds in the amygdala.
- the hippocampus stores memories about past sounds that you've encountered. The hippocampus also stores successful dealings with "stressful noise" you might have had in the past. For example, the hippocampus can store memories on how you deal with your neighbors' noise last year. Your brain can then access that memory to solve problems in the present moment. 
- the primary auditory cortex, which is the cortical area associated with sound, is responsible for dealing with more abstract types of sound, such as music. 

I think the last area is inhibited in my brain because friends have told me I've got no feeling for rhythm when I dance. You can't have it all in life...)

 

When Sound Becomes Noise

It's important to realize the situational difference between "sound" and "noise".[162; 168]

If you like rock music and you're going to a concert, a 70dB sound might not be interpreted as noise per se. If you need to concentrate on a cognitively demanding task, however, a 70dB sound emerging from a bypassing train will be interpreted as noise. 

Of course, at a certain point, all sound becomes noise. Even though you might like the sound of a shogun firing at 140dB, that sound will always act as noise for your body, because your nervous system and brain are simply directly impaired by that stimulus.

Naturally, the setting of sound also matters.

If you hear the previous rock concert music while you're trying to focus, the results might not be that optimal. And if you're presented a barely audible classical music piece at 40dB while thinking you're going to a rock concert, you won't be happy either.

Again, it's just not only decibels matter but also the nature of the sound and the situation you're in when you're exposed.

Noise inhibits your ability to be present with any current activity.

Different types of sounds have different influences in different situations, even though they might be just as loud.[252; 283; 284]

If you hear a baby crying at 40dB, for example, that specific sound trigger can have much more of an impact on your brain than hearing a far away lawnmower at 60dB.

Language is another category of sound that has a large impact on your brain. Hearing your name at 30dB in a crowd can immediately trigger your brain. Hearing spoken language at 50dB can also be more annoying when you're trying to focus, compared to hearing traffic at 70dB.

Different categories of sound thus have different influences.

 

The Danger Of Unpredictable Noise

One reason for this influence is the role of the "amygdala" brain area which I've talked about earlier. More unpredictable noises are more damaging than continuous noise exposure, and trigger your amygdala much easier.

Hearing your name in a crowd will also activate your body...

The bottom line of this section is that noise causes stress in your body by increasing stress hormone levels, activating the amygdala in your brain (the brain's alarm bell), and by creating oxidative stress which can lead to cell damage.

how sound and noise work in the human brain
(noise is like an alarm clock that goes off in your brain,
creating activation in your hormonal and nervous system).

 

Let's now look at the full health-effects of noise pollution.

One last section of gloom and doom before things get better. Hold tight... 

 

Health Effects Of Noise Pollution: Inflammation, Hearing Loss, Stress, Insomnia & Disease

In this section, I'll tell you why noise has far greater consequences than just creating hearing losses.

Many people assume that losing their hearing ability is the only negative consequence of noise. Nothing could be further from the truth: noise affects many areas of your health.

I'll tell you about these areas one by one... 

Let's consider a complete list of all the effects that noise pollution has on your body. Noise pollution:

  • lowers your sleep quality.[13; 14; 15; 16; 53; 79; 80; 81; 114; 115; 116; 117; 118; 280; 281] Of course, we all know that statement is true. We all know that if you're woken up by noise during the night, you'll no longer sleep as well as you otherwise would have.

    You're probably assuming that cats fighting outside or a thunderclap is sufficient to wake you up.

    The problem is worse though: remember that low levels of noise at 30-40dB already increase your arousal levels. A dishwasher that's buzzing in the background or a cat who's scratching the door can already inhibit your sleep quality. 

    (Yes, it's all true: cats have been in a conspiracy to ruin our sleep for millennia.) 

    But joking aside:

    Talking neighbors, laughter, music, and electrical appliances, for example, all influence your sleep quality. At that level of sound, the electric impulses - measurable by what is called an "EEG device - in your brain are altered, and the amount of deep sleep is affected. 

    To be more precise: with noise, you'll experience less deep sleep and you'll sleep more superficially. The dream stage of your sleep is also inhibited. That dreaming stage is an important part of sleep's regenerative capacity.

    Of course, interruptions of your night will also affect how you'll behave (and perform) during the day. Noise pollution at night causes you to be moodier, more likely to be annoyed, tired, slightly depressed and makes you perform worse during the day.

    Poor sleep has additional (negative) health effects as well: the levels of sugars in your blood rise, stress hormones increase, while healthy hormones levels decline. Having less quality sleep also makes you more hungry all day. 

    All these effects, in turn, increase your chances of becoming obese.[19; 20; 21; 22; 23; 24; 25]

    Besides causing disease, sleep problems obviously have many other effects as well, such as lowering your immune function, making your miss days at your job, and increasing your chances to get psychological problems.

    And because noise pollution lowers your sleep quality, memories that would otherwise get stored during sleep won't get solidified.

    Again, I cannot overemphasize the problem of noise on sleep:

    Medium levels of noise pollution may cause as many as 150 nightly awakenings on a yearly basis. A nighttime 60-65dB sound level can cause as many as 300 nightly awakenings per year, which even increases your risk for getting psychiatric disorders.

    The more types of noise are found in your environment, such as overflying airplanes, cars, and railroads, the bigger the influence on your sleep.

    In an isolated environment - where there's no noise pollution - you'll experience between 15 and 35 minutes of additional deep sleep per night, compared to noise polluted areas.

    That deep sleep increase effect is even observed in healthy people, so everyone benefits from sleeping in a silent place. People who sleep poorly might expect even bigger increases in the amount of deep sleep they get.

    Noise also forces you to take up to 20 minutes longer to fall asleep in the first place. You'll thus lose a lot of days in bed due to noise on a yearly basis...

    Overall, noise pollution is rather detrimental to sleep quality. 

    (As a side note, if you want additional tips for increasing sleep quality, read Alex blog post which contains the best tips on that topic.)

    a relaxed environment in nature
    (Nature: one of the only places where you can sleep
    without noise pollution nowadays)

    In addition, noise:

  • inhibits your ability for higher-level analytical thinking, memory, and attention.[17; 119; 120; 121; 122; 136; 151; 155; 158; 171; 177; 183; 184; 185; 190; 191; 192]

    Noise not only lowers your thinking ability through lowering sleep quality. On the contrary, noise decreases your higher-level thinking ability instantly.

    Loud traffic noise, for example, considerably lowers your ability to focus compared to the sound originating from medium-intensity traffic. 

    What's really interesting is that noise inhibits mental performance more in introverts compared to extroverts.

    I'm an introvert and I'm pretty annoyed by noises. For that reason, I'm always writing these blog posts in as much seclusion as possible. A 60dB noise, for example, will inhibit focus in an introvert, but not in an extrovert. 

    Crazy right?

    But there's more:

    Noise also impairs your brain's working memory (which helps you keep pieces of information in your mind), long-term memory, and the ability to make decisions. Even a single episode of a very loud noise can already impair the formations of long-term memories. 

    The more cognitively complex the task you're carrying out, the more noise will inhibit your performance. With more noise, you'll become more cautious overall, and your reaction times increase. 

    These negative effects occur independently of your age. 

    Simply put, noise causes your brain to allocate scarce resources to dealing with the noise instead of helping you focus. Once your brain is primarily dealing with the effects of noise, your overall attention and thinking is lowered. 

    How?

    I'll have to talk about the brain again:

    The "prefrontal cortex" is a brain area located on the front of your head. That brain area is intrinsically related to planning, working memory, being able to control yourself in social situations, and making decisions.

    Noise stress inhibits the functioning of your prefrontal cortex. 

    One reason noise stress might have this effect is because of increases in stress hormones such as "cortisol" and "adrenaline" I've talked about earlier. The higher the levels of stress hormones in your body, the less active that prefrontal cortex becomes.

    Lastly, noise may negatively affect the "GABA" signaling substance in the brain, which is concerned with relaxation. I think we're all fully aware of how noise can remove our chill feelings.

    On a more positive note:

    Interestingly enough, music can have the opposite effect of noise, increasing the activity of the prefrontal cortex. To be more precise, the music needs to be pleasurable--neutral or unpleasant-rated music will not have a positive effect.

    That's all?

    No...

    Let's consider another topic that is of quintessential import:

    Children are especially vulnerable to noise's effects on cognitive performance.[15; 123; 124; 125; 126; 127; 128; 129; 130; 131; 132; 133; 134; 135] 

    Noise lowers children's well-being and increases their stress levels. You, therefore, don't want your kid's school to be placed near a highway, railroad, or busy street.

    Children who are exposed to noise end up having lower speech perception and reading comprehension. Speech perception is the ability to hear, process, and understand language. Even test outcomes will go down if children are exposed to noise. 

    Noise can additionally lower the possibility of children and teachers properly interacting. 

    But there's more:

    What's even more astounding is that noise creates hyperactivity in children. That hyperactivity might be misdiagnosed as Attention Deficit Disorder (ADD) or Attention deficit hyperactivity disorder (ADHD), but could be noise-related instead.

    I'm sure that most parents are aware of the stimulating effects noise (and music) can have on their children.

    One reason children might be affected to a higher extent than adults is because children have less control over the noise. Furthermore, children have often not developed the coping skills to deal with noise in the first place--while adults do

    For optimal learning and development, children need to be exposed to a maximum of 55dB at playgrounds, and 35dB in classrooms.

    That 35dB sound level is very low. A classroom full of talking children can approximate 70dB, and a classroom of screaming children moves sound levels over 100dB. 

    The biggest problem with noise, however, comes from outside the classroom, such as busy roads. Such areas are often not controllable by teachers. For that reason, make sure that your child gets the best education and avoid schools placed in noisy areas.

    So, we've got lowered sleep quality and cognition. 

    What else does noise cause? Well, noise:

  • makes you anxious and depressed.[139; 140; 141; 142; 143; 147; 148; 149; 150; 152; 153; 154; 156]

    Getting exposed to just 55dB of noise on a daily basis already increases your risk for depression and anxiety. Higher noise sensitivity will literally double your chances for getting depression, insomnia, and anxiety.

    Noise is not a side-issue: with long-term exposure, you can even end up with a mild cognitive impairment. The more sensitive you are to noise, the worse the effects on your mental health will be. 

    Once you're continually exposed to 70dB of sound, your anxiety levels shoot up. The relationship between noise and anxiety is linear: more noise results in more anxiety.

    That's the bad... 

    Now the ugly:

    Anxiety and noise essentially lead to a vicious cycle: being anxious, you're more prone to respond negatively to noise, which will make you even more anxious in turn.

    It's also interesting that noise can make already scary situations worse. The sound of drilling at a dentist, for example, can increase already existing anxiety. Another example: if you merely think that airplanes are prone to crash, you'll also react stronger to airplane noise in your neighborhood. 

    A signalling substance in your brain called "dopamine", furthermore, may also be affected by noise. You need dopamine to be motivated, assertive, feel good, and proactive.[137; 138] 

    Some studies show that dopamine lowered due to noise, while others demonstrate that it increases. The difference between lowering and increasing dopamine levels can probably be explained through the short versus long-term effects of noise. 

    In the short-term, noise will make you more active, increasing dopamine levels. But if you're exposed to noise too often, your overall dopamine levels go down. 

    Dopamine is absolutely essential for your physical and mental health.

    Next, noise:

  • gives you a higher likelihood of having cardiovascular disease.[52; 62; 114; 144; 146; 163; 164; 165; 198; 199; 202; 203; 204; 205; 222; 223]

    The more noise you're exposed to, for example, the higher your chances for getting "hypertension" - which is commonly known as "high blood pressure". 

    If you're living in a noisy neighborhood, having a house with thin glass or without multiple layers of glass will already increase your chances of getting hypertension. Sleeping near a window that's located on a busy street, moreover, also makes getting hypertension more probable. 

    If you're exposed between 45dB and 75dB background noise, every 5dB increase in sound gives you a 14% increased chance of getting hypertension. Those percentages are cumulative, so 10dB will yield a 1,142 = ~30% increase for getting high blood pressure levels.

    And a 30dB increase? I don't even want to know the answer...

    Not only hypertension risk is increased due to noise, however. Noise also increases your risk for getting a heart attack. 

    Why? 

    Again, noise is a chronic low-level stressor that lowers your overall health.

    Stress affects heart function through several mechanisms, such as increasing the thickness of your blood, activating blood clotting, altering how you deal with sugars in your blood, and lowering the health of your blood vessels.

    The end result is having a higher risk for getting a heart attack.

    But to end on a more positive note:

    If you're at risk for getting heart disease, please read the following blog posts  - which can help you: 1) conquering (chronic stress; 2) using sunlight for health; 3) using red light therapy to mitigate (part of) the effects of not having enough sunlight exposure; 4) improving sleep quality.

    All four articles can help you manage your heart disease. 

    (Of course, make sure you're lowering your noise exposure as well.)

    Next, noise:

  • increases your probability of having a stroke.[216; 217; 218; 219; 220; 221]

    Different types of noise have different effects on your chances of getting a stroke. Traffic-related noise, for example, seems to increases your chances, while industrial noise may have less of an effect.

    Once traffic-related noise exceeds 75dB, your risk for getting a stroke will increase much quicker than at lower levels. Airplane traffic has the same effect.

    Because many cities have noise levels close to 80-90dB, these locations are more dangerous for your stroke chances. 

    As very often, the more annoyed you are by noise, the more damaging the effects will be - and thus the higher the chances for getting a stroke. 

    Older people are also at higher risk for getting strokes due to noise pollution. I assume the reason is that older people have less leeway with their health in general.

    What's also interesting (and scary) is that if the areas are high in air pollution, that risk may be added on top of the health damage created by noise. And of course, areas that contain lots of noise often also have very high traffic levels - traffic is a common source of both air and noise pollution.

    The bottom line is that you need to manage noise if you're already at risk for having a stroke.

    As often, there's more...

    Noise also:

  • may decrease the functioning of your immune system and increases inflammation.[206; 207; 208; 209; 210; 213; 214; 215]

    Remember that noise increases that stress hormone called "cortisol" in your body? 

    As a result, the body's inflammation levels can increase. Excessive inflammation is related to many modern diseases, such as cancer, heart disease, and autoimmune conditions.

    Part of the increase in inflammation can be explained through noise causing a deterioration of the heart and blood vessels. 

    Stress by itself, moreover, is also often associated with higher inflammation levels. Of course, noise is stress - and therefore increases inflammation levels.

    But there's more:

    Even immune cells may be affected by noise--although more human studies are needed. What's remarkable in animal studies is that noise can even affect the functioning of the immune system of the eventual offspring, when mothers are exposed to noise during pregnancy.

    Overall, we can draw one solid conclusion: noise won't make your immune system function any better.

    (Fortunately, the list is almost finished. Creating this long list on noise's negative effects makes me somewhat sad)

    Noise:

  • increases chances for getting diabetes.[144; 163; 224; 225; 226; 227; 228; 229; 230; 231]

    There are several mechanisms through which (chronic exposure to) noise promotes diabetes:

    - firstly, blood glucose levels are altered through noise. Your blood glucose levels shoot up at higher sound levels, such as 85dB
    - secondly, noise disrupts your (stress) hormones. More stress hormones aid in causing diabetes.
    - thirdly and lastly, sleep quality is altered. Poorer sleep means having a higher risk for getting diabetes.

    If you've got a common residential sound exposure level higher than 65dB, for example, you're at 22% greater risk for diabetes. People who have their windows opened all the time, moreover, have an increased risk for getting diabetes - at least if they were living in a noisy area.

    Every 10dB increase in road traffic seems to increase diabetes risk by 25%. That risk is cumulative, so a 20dB increase leads to a 56% increase, instead of a 50% increase.

    Again, city life is not all it's held up to be...

    And then, noise:

  • makes you gain fat.[231; 232; 233; 234; 235; 236] 

    Yes, really. The fat-gain is closely related to the effects that noise has in causing diabetes. Noise simply affects the metabolism in your body - the processing of energy - thereby causing a cascade of effects such as heart disease and diabetes.

    Even during pregnancy, noise exposure already predisposes a child for fat-gain later on in life.

    While no direct human studies have been carried out, in animal studies high levels of noise of 95dB cause immediate metabolic problems.

    Stay with me. 

    We're almost done with the list of noise's health effects. 

    Noise:

  • simply makes you annoyed.[55; 56; 57; 58; 59; 60; 61; 69; 165] 

    Yes, noise thus causes direct psychological stress. Annoyances due to noise pollution - as so many other issues associated with noise - are not a minor problem.

    When rating an annoyance level from 0 to 10, people locate their annoyance from traffic noise at a 7-8 level.

    The result? 

    Anger, anxiety, depression, apathy, and disappointment. Additionally, your quality of life goes down with increasing noise levels.  

    In essence, that quality of life decline caused by noise can be explained in several ways. Firstly, you'll have fewer options to truly relax. Secondly, you'll experience more negative and a lower number of positive emotions. Thirdly, you'll be interrupted in activities you're engaged in.

    One often-experienced annoyance, for example, is the need to keep one's windows closed at all times. Opened windows dramatically increase indoor noise pollution levels. The end result, however, is not getting enough fresh air into your home and that you'll feel closed off. 

    Annoyance is pretty subjective though. Some people are more prone to be annoyed by noise than others. Overall, if annoyance exists due to noise, your quality of life is lowered. 

    I wonder how many fights are created on a yearly basis, as a side-effect of too much noise originating both inside and outside the house? Don't want to think about that now...

    Lastly, let's talk about the most "famous" side-effect of noise. Noise:

  • induces hearing loss.[64; 65; 197; 200; 201; 202; 203]

    If a sound exceeds the 85dB threshold, hearing loss is induced. On a 24-hour weighted average basis, that number drops to 70dB.

    If you work in an industrial setting, it's likely that you may be exposed to such noise levels. Never operate loud machines or stand next to noisy loudspeakers without protective gear...

    Fortunately, during the last few decades, most people have actually started wearing protective ear-wear to avoid hearing loss.

    That's a great win, actually. 

    But you know what?

    Even though hearing loss due to industrial settings has decreased, social causes of hearing loss are increasing. More and more people are listening to music that's way too loud - either individually with music players, or through going to concerts. Alternatively, people acquire hearing loss due to traffic.

    Hearing loss is not just irritating but also dangerous because without well-working ears you're much more prone to get in accidents.

    It's important to understand that your hearing automatically deteriorates the older you get. Noise just speeds up that process of deterioration. 

    Why?

    In hearing loss, specific cells in your inner ear are damaged. It's generally accepted that these cells cannot regenerate, meaning that hearing loss is (currently) irreversible. 

    Fortunately, stem cell treatments - stem cells the primordial cells in the body that can differentiate into specialized cells - may be able to deal with hearing loss in the future.

    So there's hope for people with hearing loss.

Hallelujah...

I'm happy that depressing list of problems caused by noise is finally finished. 

Before we look at solutions, however, let's take a look at individual differences in dealing with noise. Not everyone is affected by noise in the same way.

 

Noise And Demographics: Who Is Affected Most By Noise?

Some groups are influenced by noise to a far greater extent than others. Let's consider the first group:

Firstly, children are the most susceptible to noise.[98; 99; 100; 107; 108; 109; 124; 171]

That problem doesn't just exist after children are born:

Hearing defects are already diagnosed in fetuses today - hence before children are even born. How? Noise pollution such as road traffic penetrates the mother's belly, thereby affecting the fetus. 

The results of excessive noise during pregnancy are birth defects, hearing loss, growth problems, and children being born (too) early.

The problems for children don't stop there:

After birth, excessive noise can cause helplessness, cognitive problems such as an inability to concentrate, impaired learning ability, nervousness, and increased blood pressure. 

For every 10dB increase of average (average daily) sound exposure before the age of 7, behavioral problems increase with 7%. More noise additionally makes children's "academic  performance" go down, even after the age of 7.

Overall, you'll want your (not yet born) child to steer clear from noisy areas.

Shift workers are the second category of people who are harmed more by noise than the general public.[110; 111; 112; 124]

I've you've been following my blog for a while, you know by now that shift work is no bueno for your overall health.

Shift work increases your chances for all kinds of diseases, such as heart disease, obesity, diabetes, cancer, and autoimmune disease.

And because shift workers often sleep during the day their sleep quality is even more disturbed by noise compared to people who sleep at night.

Why?

During the day almost everyone goes about their daily activities - which are often accompanied by at least some noise generation. At daytime, there's thus more traffic, more machinery being operated, and more "social" noise.

Construction crews are often prohibited from working during the night due to the noise being generated. People working shifts are directly affected by construction noise if they try to sleep during the day.

But there's more: you're also more susceptible to noise if you sleep during the day in the first place. For some reason, the same dB level of noise affects you more during the day than during nighttime.

(I think the reason is that shift-work is inherently stressful, incapacitating your body's defense against new stresses)

Noise is thus another nail in the coffin of shift work...

Solution?

There is none...

If you're working night shifts, make a plan to quit them as quickly as possible. Also make sure, moreover, to lower your noise levels as much as possible during your sleep periods if you're working shifts anyway.

(Fortunately, the next section will give you several strategies to lower noise levels)

Thirdly, people become more affected by noise with age.[124; 127; 291; 292; 293]

Elderly seem to be especially annoyed by very low tones of noise, such as bass.

The more people are aware of the negative effects of noise - which happens to occur once you grow up - the more people are annoyed by noise as well.

At very old ages, however, annoyance levels due to noise go down again - probably due to hearing loss. That means that there are at least some upsides to aging...

Fourthly, the negative effects of noise also increase in some specific psychiatric mental disorders.[124; 157; 159; 160; 179; 180; 181; 182; 183; 294] 

Let's consider two examples, such as Schizophrenia and Autism...

In general, persons diagnosed with Schizophrenia have trouble with motivation, processing information, controlling their emotions, and may lose contact with external reality due to (excessive) noise.

To be more precise, people with Schizophrenia have trouble diverting attention away from noises. Noises may also be processed in a different way if you have Schizophrenia. 

It's not a coincidence that Schizophrenia levels are double in urban environments compared to rural areas. The more "noise stress" there is in your location, the worse the symptoms of Schizophrenia become.

Moreover, in autism or Asperger's syndrome - which are both developmental disorders - noise makes it more difficult to understand speech. People with these disorders are also more commonly hypersensitive to sound. The more different types of noise are present, the harder focusing becomes because useful sounds get harder to filter out.

(As a funny side note, some people are annoyed with specific types of sounds very quickly, such as slurping, the sound of eating or sniffing. Although these annoyances are not an official psychiatric disorder, they may indicate a degree of compulsiveness.)

I had to integrate some humor into this blog post...

Fifthly, there are individual differences in how well people tolerate noise.[124; 145; 168; 172; 173; 174; 294; 295; 296]

Let's say you're really sensitive to noise.

In that case, you're more attentive of noises in your environment, you'll discriminate noise more from other types of sound, accept noise something that's outside your control and therefore see it as more threatening, and you'll have problems adapting to noise in the first place.

The more "neurotic" you are, moreover, the more you'll actually be affected by stress - such as noise. 

There's also a "gender gap" with noise pollution:

Men, for example, are less able to deal with traffic noise than women.[81] In other areas, such as vigilance or brain processing speed, women are more affected by noise than men.

What's interesting is that people do indeed get used to noise to a small extent over time.[81; 118] In sleep labs, for example, where participants might be subjected to loud noise several nights in a row, have significantly worse sleep during the first night compared to later nights.

However, that effect of "getting used" to noise might also be due to participants getting used to sleeping in another environment, compared to getting used to the noise...

The human adaptability to noise might thus be overstated.

What's important to understand (and remember) is that no-one will ever fully adapt to noise. In other words, you might get partially used to 80dB noise levels, but that noise will still always have negative consequences for your health.

Yes, that's true even if you claim to be "not sensitive" to noise.

So what are the implications of the previous sections up until now? 

Noise has become negative byproduct that's intrinsically intertwined with how our modern society is structured.

Don't be bogged down though: in the next installment of this series, you'll learn about what you can do about noise.  

Why?

Genetics, on the one hand, does influence how well you're able to deal with noise. Implementing a few practical solutions, however, will have a greater influence on your annoyance levels than your genetics.[237] 

Let's go...

 

Finishing Thoughts: Counter Noise Or Suffer The Consequences!

The bigger picture?

24-7 or even incidental noise is one of those things that is slowly killing you even without you knowing it...

Just like people weren't aware of the negative health effects of drinking a few cans of sugar-rich soda per day, or sitting on the couch 24-7, many are unaware of noise as well.

Noise is not just a nuisance! Instead, noise is a real force of sound that negatively affects your health.

My solution?

Stay tuned because I'll give you lots of strategies to work with in the next installment of this series! 

Hopefully, you're convinced that noise is a problem now! Higher heart rate, insomnia, poorer blood sugar management, and many other consequences are a result of noise pollution. Take charge!

 

 

This is a post by Bart Wolbers. Bart finished degrees in Physical Therapy (B), Philosophy (BA and MA), Philosophy of Science and Technology (MS - Cum Laude), and Clinical Health Science (MS), and is currently a health consultant at Alexfergus.com. 

 

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