This is a guest blog post by Bart Wolbers. Bart runs a health blog at Nature Builds Health and helps you take charge of your own health.


Bart finished degrees in Physical Therapy, Philosophy (BA and MA), Philosophy of Science and Technology (MSc – Cum Laude), and Clinical Health Science (MSc). As a personal challenge, he completed his three Master’s degrees simultaneously.


Why Your Environment Matters For Your Health


Many people begin their health journey dealing with diet and exercise. For some people, diet comes first — for others that’s exercise.


After some period of time, you’ll probably find that eating well and spending some time in the gym is not sufficient for optimizing your health – sleep matters tremendously as well, for example.


So if you’re doing Crossfit 4 times a week and eating well, but you’re sleep deprived all the time, you’ll still be in trouble long-term.


My journey in understanding health was more than food and exercise was similar.


I started exercising when I was 15 and learned about the importance of diet at age 17. For years, I did lots of heavy weight training 4-6 times a week. Only 10 years later was my vision on health radically changed – I used f.lux to block blue light from my computer screen at nighttime and immediately noticed the difference in sleep quality.


That’s when started thinking and doing research.




I’m 33 now and have researched the effects of the environment upon health in great detail.


So in this blog post, I’ll go through the effects of several types of environmental influences that are not frequently talked about.

Let me explain:


Many people today know that the light in their environment affects their health. So you may know to get your sunlight exposure during the day and block the light emitted by screens and light bulbs at night.


And that’s great.


But other influences in your environment can affect your health as well. The air you breathe, the sound that enters your ears, and the temperature of your environment have huge influences too.


So let’s go over these domains one by one:


1. Air Pollution And Health


Consider some numbers to convince you breathing toxic air really is a problem:


In Europe as a whole, air pollution causes 800,000 deaths every single year (7). Of course, it’s mostly elderly and already weakened people who are dying from air pollution, but unfortunately, these people do die


In the US, deaths are only estimated at 70,000, although older and obsolete types of calculation are used (50).


In fact, if you’re consistently exposed to heavy air pollution you’ll cut your life short by a couple of years (8).


So if you’re living close to an airport or a busy road, your health is almost certainly negatively affected by that location. And if you’re living in the middle of nowhere in the woods, the air you breathe will improve your health rather than take it down.


What air pollutants exactly?


Well, you may be aware of a few air pollutants such as carbon monoxide and mold and actively try to avoid them (1; 2; 3). And that’s great. But factories, power plants, and traffic also emit multiple toxins.


Let’s conisder three of these pollutants one by one:

1. Nitrogen Dioxide


Nitrogen dioxide is a gas that’s mostly sourced from traffic exhaust and energy creation. Lung health is negatively affected by inhaling that gas.



Nitrogen dioxide increases your overall risk of dying (4; 5). Specifically, your risk for lung conditions (including cancer) and heart disease go up.


And it’s not just one or two people dying of nitrogen dioxide exposure.


Shocker: almost 12,000 people are dying every year in the United Kingdom due to nitrogen dioxide exposure (6). Terrorism kills fewer than 10, and yet, that’s what all the media is focused on.


(By the way, I’m not fear mongering here – in the latter part of this section I’ll tell you how you can defend yourself against this danger.)


In that same UK, “only” 1,700 people are killed by car accidents. So it’s interesting that media are not covering the tragedy of air pollution in more detail.


And in addition to nitrogen dioxide, there’s particulate matter – “the king of air pollutants”:


2. Particulate Matter


Particulate matter is extremely tiny little particles that enter your body through breathing. These particles have a diameter that’s ~10-1000 fold as small as a human hair.


These particles so small that they can end up in your bloodstream from your lungs, and may even directly travel to your brain through nerves found in your nose (7)


Due to that mechanism, many bodily processes start to function less well at the cellular level with more particulate matter exposure.


The shocker?

Even the World Health Organization assumes that 7 million people die every single year due to particulate matter exposure (8)


Alcoholism and alcohol abuse “only” kills 3 million people each year (9). Terrorism, which you hear about the news every single day? 18,000 (10).


Now you know about the priorities of the media.


A simple solution to the particulate matter problem doesn’t exist though: cars, airplanes, industry, and energy plants emit most particulate matter. Deserts are another source of particulate matter because winds can carry sands for thousands of miles.


Indoor cooking, is counterintuitively, the most important source of particulate matter. Many people in Asia and Africa still cook on op an open fire indoors, which exposes them to terrible levels of particulate matter.


Even if you’re living in the developed world, use your cooker hood to remove some particulate matter form the equation. Cooking with an open fire, however, remains the foremost danger in particulate matter exposure – which many people in the developed world don’t use.


So how is particulate matter so damaging?


Let’s find out. Particulate matter:


  • Increases your risk for heart problems, such as an altered heart rhythm, blood vessel dysfunction, high blood pressure, and atherosclerosis (narrowing of blood vessels due to calcium deposits) (11). You’ll also increase your risk of having a stroke (12).
  • Impairs your ability to breathe properly (13). Lung function goes down, which is especially problematic if you’ve already got lung disease. Even if you’re healthy, particulate matter exposure will lower lung function (14). Lowered lung function may make you more stressed in everyday life and lower your athletic performance.
  • Boosts stress hormone levels (15). That’s right: Just  being exposed to particulate matter has the same effect as psychological stress. Over time, particulate matter may also create stress in tissues such as the brain and other organs, lowering their capacity (16)


Not so nice, right?


(I’ve published an extensive guide about the damaging effects of particulate matter before if you’d like to learn more)


Let’s move to the third air pollutant:


3. CO2


CO2? Isn’t CO2 just a greenhouse gas?




But there’s another side to the story:


Modern humans spend more than 90% of their time indoors (17). And if you’re staying indoors you’re probably also closing your windows most of the time. Simply due to your breathing, CO2 levels will increase over time in that case.


Let me explain why CO2 levels get higher and higher over time: You breathe in oxygen, and breathe out CO2. Over time, more and more oxygen in the room is thus replaced with CO2.


That CO2 can subsequently make you drowsy and lower your cognitive performance (18; 19).


Classrooms or offices that contain many people in a tight space are most at risk of having very high CO2 levels. CO2 levels in such rooms can become over 10 times as high as outdoors.


The solution to high CO2 levels is simple, of course: Just open up your windows once in a while and you’ll let the CO2 leave and make fresh oxygen enter.


Or is the solution that simple?


Won’t you let many new toxic air pollutants enter the building if you open up your windows?

Let’s find out:

Dealing With Air Pollution


Scared yet?

I hope so – you’ll become motivated to deal with the problem. Let’s go over a couple of solutions that can cut your air pollutant exposure by up to 95%:


  • Use an air purifier if you’re living in an area with lots of traffic or industry. Use the Air Quality Index map to get a feel of how polluted the area you’re living in is. Air purifiers, which I describe in great detail in my guide on surviving the health effects of air pollution can lower the amount of particulate matter, mold, and biological pollutants such as animal dander and pollen by up to 90%.
  • Get fresh air into your indoor environment once in a while. Not only will CO2 levels build up over time, indoor environments frequently contain up to 5 times as many air pollutants as outdoors (20). Don’t open your windows all the time if you’ve got an air purifier though, as the purifier would work overtime every day.
  • Eat healthily and exercise. Healthy food reduces the damage caused by air pollutants and gives you more leeway if pollutants have an impact. Exercising builds up your heart and lung health, which are broken down by several air pollutants. Make sure not to exercise in polluted areas though: exercising in polluted areas expose you to more pollutants because you breathe quicker (21; 22).
  • Avoid polluted areas as much as possible. Avoiding rush hour can cut your air pollutant exposure in half, for example. Avoiding the city center or highway accomplishes the same goal.


By just implementing these strategies you’ll literally cut your exposure by 95% – even if you’re living in the city.


So let’s move to the next domain, a problem that’s considered far more irritating to many people:


2. Noise Pollution

Remember that time your neighbor threw a party at 2 AM?


How about that other neighbor who’s playing loud music during the night?


And recall those cats fighting when you were asleep?


That’s right: were asleep but the noise woke you up.


Many people think that noise is just a nuisance that leaves you irritated. Nothing could be further from the truth.


Noise has real biological effects and affects many areas of your health. But before considering health effects, let’s have a look at what noise fundamentally is. To understand noise I’ll have to begin with sound:


From a physics perspective, sound is a vibration. Air is the medium by which most sound is propagated.


Sound levels can be measured in many different ways, but all of these measurements revolve around the “decibel scale”.


That decibel scale starts at 0 and has a maximum level somewhere around 200. If decibel levels exceed 194, shockwaves are created. Shockwaves are no longer considered sound.


It’s important to realize that the decibel (dB) scale is logarithmic. In this context, logarithmic means that for every 10 dB increase in sound levels, sound levels increase 10-fold.




Consider that neighbor who plays music at 50 dB at night. If he increases that sound level to 60 dB, the level of loudness has increased 10-fold, not just 20%. From a numerical perspective, to arrive at 60 takes a 20% increase from 50. The logarithmic scale is thus different.


Let’s consider a few sound levels:

  • At 10 dB, you can only hear yourself breathing and you’d notice the dropping of a pin
  • The sound level of whispering in a room is located at 40 dB
  • Music and showering have a sound level of around 70 dB
  • 100 dB is experienced while standing close to an airplane that takes off, or the sound of a motorcycle
  • 130 dB – peak noise levels in a football stadium


So how to separate “sound” and “noise”? Simple: When sounds irritate you or stress you out, it becomes “noise”.


Noise is omnipresent in today’s society. I’ll explore why in a second.


Nature is generally free from extreme noise, except for the occasional 110 dB + thunder and some roaring animals. Birds that sing and crickets that make sounds only approximate 40 dB.

The problem?


Many cities have continuous 50 – 90 dB levels – even at nighttime. 50 dB sound levels are 10 times as high as 40 dB in nature, and 90 dB is 100,000 times as high.


Crazy right?


And the problem?


Institutions such as the World Health Organization approximate that sound levels of 40 dB are acceptable at nighttime (23).

So let’s look at how everyone is doing:


In the US, however, many people experience over 70 dB over a 24-hour period (24; 25). The average street in New York City has noise levels of 70+ decibels (28).


In a big City like Hong Kong, nighttime noise levels can range from ~50 – 70 dB, which is 10-1,000 fold to high for optimal sleep quality (26). In Indian cities, levels range between 70 and 110 dB during the daytime (27).


Let’s look at the health consequences of noise pollution. Noise pollution:


  • Is inherently stressful and associated with a “fight, flight or freeze” response. In nature, noise often acts as a warning sign (30). A predator attack is often paired with loud noise, for example. If you’re continually exposed to noise pollution a “fight, flight, or freeze” response will be triggered in you.
  • Lowers sleep quality (33; 34; 35). You’ll wake up more frequently with noise pollution, for instance. As a result, you’ll be sleep deprived during the day, tired, irritated, and easily annoyed. Diabetes and heart disease risk also increases. Sleep disorders such as insomnia or hypersomnia (continually oversleeping) are also common with consistent noise pollution exposure.
  • Lowers cognitive performance. You’ll have slower response times with noise, for instance (36). Overall performance also goes down because you’re less able to keep attention at the task at hand (37).
  • Can negatively affect mental health over time, increasing your risk for anxiety for example (31). That risk is literally doubled. In children, noise can also cause behavioral problems over time (32).
  • Causes oxidative stress. Oxidative stress is inherently created as a byproduct of energy creation in your cells, but if excessive, can quicken aging and lower how well cells function (28; 29)


Bottom line: You’ll get sick, stupid, and slow with continuous noise pollution exposure.


Don’t worry though: You do have control over your exposure level somewhat. I recommend several options to lower the effect noise has on you:


  • Wear earplugs or hearing protectors if you’re engaged in cognitively demanding work. Yes, hearing protectors are that weird thing you put on your head when you’re working with a jackhammer or lawnmower. I sometimes wear these hearing protectors when I need to focus on writing.
  • Use a white or pink noise machine while you’re sleeping. White or pink noise gives your ears a continuous input of “noise”. Such background noise lowers the intensity of peak noise in your environment. Peak noise, such as a sudden overflying airplane in an otherwise silent environment, is far more disrupting than continuous exposure. With less peak noise a white or pink noise machine can help you sleep better.
  • Follow a healthy diet and exercise. Yes! Just as with air pollution, simply having healthy habits in place protects you against some of the damaging effects of noise pollution. Does that mean you can now visit a rock concert without earplugs? No…
  • If you’re living in a noisy area, think about altering the construction of your house. The least invasive steps would be to install acoustic panels within certain rooms such as the bedroom. The most invasive options would be to isolate your walls and especially windows better, so that noise doesn’t enter the building in the first place.


Want to know more about noise? Read my guide about noise pollution for more elaborate explanations and other strategies to counter that demon.


And I’m not done yet.


One more topic to treat:

3. Indoor Temperature

The easiest way to burn body fat?


Many people are acquainted with cold showers and ice baths today.


Cold exposure (at the proper intensities) has tons of different benefits, such as:


  • Improving perceived sleep quality (38). Everyone needs to “upgrade” their sleep quality today. About 1 in 3 people are chronically sleep deprived, and getting some cold exposure during the day may help you with that problem. Don’t apply cold close to bedtime though as you may be too amped to sleep.
  • Lowering fatigue and stress when applied correctly (39). Lowered fatigue is an indication you’re recovering more quickly from your workouts and that you can workout more quickly again.
  • Enhances mood and makes you feel very awake (40). If you’re immersed into a cold bath for some time, adrenaline levels increase more than 500% and dopamine levels by 250%. Adrenaline makes you feel awake, and dopamine makes you feel motivated and assertive while boosting your thinking skills
  • Increases circulation (41). After you’re exposed to cold for some time, blood flow massively increases. At first, the body constricts most of your blood vessels – especially in your hands and feet – when exposed to cold water. The reason for blood vessels constricting is that your body protects its organs. Over time, however, that response levels off and overall blood flow improves.
  • Helps you lose body fat (42). The mechanism by which fat loss increases is a boost of your metabolic rate. Metabolic rate denotes the calories you’re burning 24-7, even if you’re watching television or sleeping at night. The reason for that boost in metabolic rate is that cold exposure builds “brown body fat” in your body. (43; 44). Brown fat is located around your neck, upper spine, and chest, and burns the regular body fat mostly located at your hips and belly. The more brown fat you build, the higher your metabolism and greater your ability to burn regular body fat.


Many other benefits exist as well, such as increasing the amount of muscle mass you carry, possibly preventing many modern diseases such as diabetes and heart conditions, lowered inflammation, and more.


Don’t have time to grab a cold bath every week?


In that case there’s an easy solution: Turn down the thermostat. If you’re experiencing mild cold over a longer period of time, you’ll get many of the benefits which I’ve mentioned above.


The latest science actually shows that lowered indoor temperatures increase your metabolic rate and can help you burn body fat (45).


Why does that effect matter?


Well, modern human beings have gotten very comfortable with steady indoor temperatures.


Your ancestors weren’t that lucky. During large periods of the past millions of years, the whole of North America, Europe, and the Northern parts of Asia were fully submerged under ice.


Global temperatures were also much cooler than today in some periods. Your ancestors thus had to warm themselves much more than you have to do today.


Remember that in contrast to primates, humans have lost their hair. That hair loss allows for more sunlight exposure but also cools you down. Hair keeps you warm, and the loss of hair may have been paired with an increase in the importance of the role of clothing.


And even though humans may have worn clothing millions of years ago, they didn’t have the extremely stable temperatures you’re exposed to today. So even with clothing, you’d be exposed to more colder (and hotter) moments back then than people living today.


Let’s do indeed get back to today:


If your indoor temperature is continually located at 24 degrees Celsius (75F) then your body has to put very little energy towards warming you up.


With lower temperatures, that need increases dramatically.


(Keep in mind that there’s a male-female distinction in what temperatures are considered “warm”. At 21 degrees Celsius (~70F), most women will feel cold in normal clothing while men feel comfortable (46).)


There’s no excuse almost anyone can make to avoid integrating some cold exposure into their lives:


Exposing yourself to cold intermittently can have health benefits even if it’s just through manipulating the thermostat. Spending a couple of hours in the cold will build your body’s brown fat stores.


Carrying more brown body fat on your body has many benefits, including increased energy expenditure, a better hormonal profile, prevention of modern metabolic diseases such as diabetes, better insulin sensitivity (so that carbohydrates you eat are stored in your muscles instead of as body fat), and more (47; 48; 49).


Just lowering the thermostat with a couple of degrees Celsius  already burns up to hundreds of extra calories per day. Cold environments may also incentivize you to move more, which is a huge benefit if you’re working a desk job.


Of course, if lowering the thermostat is not a possibility for you (because your colleagues would become angry, for example), then using cold showers and ice baths may be the perfect outcome.


Want to learn more about cold exposure? In that case, read my blog posts about cold thermogenesis and cold water immersion.


So now that you understand that your environment does play an important role in health, let’s conclude:

Conclusion: Your Environment Does Matter For Optimizing Your Health.

A proper diet and exercise move the needle into the right direction for your health, but they’re in no way sufficient for keeping you healthy.


Many other domains matter as well, such as your light exposure, sleep quality, your posture, and more.


So if anyone is selling you a few bone broth supplements with the claim that you’re going to get fundamentally healthy from that food, they’re either misled themselves or lying to you. And if anyone tells you that exercising 5 times a week is sufficient to stay healthy, the same is true.


Health can be more complex than many people realize.


Originally posted 2019-06-27 08:47:28.