Less Breath: Better Health? (Mouth Breathing vs. Nasal Breathing)


The following is the transcript for the video by the same name on my channel “What I’ve Learned
,” originally posted on April 12th, 2017.

The hit Netflix series “Stranger Things” has done a great service to its viewers. While it has an excellent story with a good sense of mystery, humor, horror and a loveable cast, what I’m talking about is…

Mike to Eleven: “mouthbreather – y’know, a dumb person?”

This phrase actually only comes up 3 times, but hopefully it made viewers more aware of how they are breathing throughout the day. As the character Will Mike explains, Mouth Breather refers to a “dumb person,” 

But is it because leaving your mouth open just looks dumb or you could say the person is dumb for not being aware of their own face, or does breathing through the mouth actually decrease intelligence somehow? Actually, there is evidence that simply taking air into the mouth rather than the nose can result in reduced IQ.

A systematic review of medical literature done by the Federal University Sergipe in Brazil found that after applying certain criteria Overall, 80% of the articles showed a higher incidence of learning disabilities among mouth breathers,” concluding that “This systematic review has shown that mouth breathers are more likely to have learning difficulties than nasal breathers.”


In the book “Adenoids and Diseased Tonsils: Their Effect on General Intelligence” by Margaret Rogers, she quotes a H. Addington Bruce saying “… mouth-breathing means difficult breathing, and this in turn means deficient [oxygenation] of the tissues, with a resultant lowering of vital activities generally and of the activity of the brain in particular. “

Shut Your Mouth and Save Your Life : George Catlin : Free Download, Borrow,  and Streaming : Internet Archive

George Catlin, author of the 1869 book “Shut your mouth and save your life” stresses the importance of breathing through your nose at all times, while awake or sleeping. He says “there is no perfect sleep for man or brute, with the mouth open; it is unnatural, and a strain upon the lungs” and he describes how impressed he was to see a Native American woman gently press on the lips of her baby to keep its mouth closed while sleeping. 

But how could simply getting Oxygen from one route rather than another be so important that it affect your cognitive ability or anything else for that matter? 

The nose is extremely complex and takes up much more space than just the knob in the middle of your face.  That’s only only 30% of it and the other 70% of the nasal cavity is deep in the skull. While smell is a very important sense, it wouldn’t be necessary to allocate all that real estate unless the nose had other important responsibilities. 

When someone breathes through the mouth, they are bypassing several critical functions of the nose. To name a few, the nose filters, warms and moistens the air you breathe to make it more suitable for your lungs. Nasal breathing also increases levels of nitric oxide, a key signaling molecule used throughout the body. Another very important function of the nose is that it regulates airflow and helps prevent overbreathing. 

So how can you ‘over breathe’? Well, breathing in and out more air than is necessary results in hypocapnia, or a state of reduced carbon dioxide in the blood. This is why people breathe into a paper bag when hyperventilating from intense stress or an anxiety attack. The excessive breathing depleted too much carbon dioxide, so the bag helps trap the carbon dioxide they are exhaling and keep it in the body until their carbon dioxide blood levels and breathing rhythm return to normal. And this is a key point in why mouth breathing can affect people’s intelligence.

Breathing through the mouth during the day or while you’re asleep not only means the air is not conditioned by the nasal cavity, but you tend to exhale too much carbon dioxide, meaning your tissues are actually getting less oxygen. And, lower carbon dioxide within the blood causes a constriction of the carotid artery, the main blood vessel going to the brain. “Each 2.5% drop in the partial pressure of arterial carbon dioxide reduces blood flow to the brain by 2%.

The loss of carbon dioxide from improper breathing isn’t drastic enough to be easily noticeable, but over time the habit can take its toll on the brain and body.

But this is a bit counter intuitive. How could taking in more air through a bigger passage – the mouth, lead to less oxygenation of your tissues?  People mainly think of oxygen when discussing breathing, but Carbon Dioxide is a key factor in this equation.

Amazon | The Oxygen Advantage: The simple, scientifically proven breathing  technique that will revolutionise your health and fitness | McKeown,  Patrick | Sleep Disorders

As Patrick McKeown, author of the Oxygen advantage explains, “The amount of Oxygen, your muscles, organs and tissues are able to use is not entirely dependent on the amount of oxygen in your blood. Our red blood cells are [almost always] saturated with between 95 and 99% oxygen and that’s plenty for even the most strenuous exercise.” So, since your red blood cells are already saturated with oxygen, taking in more oxygen with big breaths isn’t going to do anything. 

What is important, is getting that Oxygen out of the red blood cells so it can be used by the body. And Carbon Dioxide is what allows the release of oxygen from the red blood cells. This physiological phenomenon is called the Bohr effect, it was first described in 1904 by Christian Bohr and it states that “hemoglobin’s oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide.” Hemoglobin is the protein inside red blood cells that carries oxygen. An increase in carbon dioxide decreases blood pH and hemoglobin proteins release their load of oxygen so it can be utilized by the muscles and organs.  A decrease in carbon dioxide increases pH and causes haemoglobin to hold on to more oxygen. That is, the oxygen stays stuck to the hemoglobin so it’s not available for your tissues to use. 

Carbon dioxide is created as an end product of metabolism. So, the Bohr effect helps oxygen be released to the tissues most in need of oxygen. For example when you’re running, your thighs are going to be using a lot of energy, the metabolic rate will increase and the thighs will produce more carbon dioxide. This extra carbon dioxide will then let the hemoglobin supply more oxygen to these hardworking muscles.

However if you’re taking large breaths through the mouth, you’re going to exhale and lose a proportionally large amount of precious carbon dioxide.

Patrick McKeown explains that if we breathe a lower volume of air by breathing in a slow controlled fashion through the nose, we increase the amount of carbon dioxide inside us and can deliver more oxygen to our muscles and organs, including the heart and the brain.

So what’s important is not having enough oxygen, but being able to use that oxygen. Unless you have some serious pulmonary problems, your red blood cells will always be almost fully saturated with Oxygen. If you don’t have enough Carbon Dioxide in the blood because you’re breathing too heavily or through the mouth, you can’t use oxygen efficiently and bringing more Oxygen into the lungs with a big breath won’t help you. 

Ironically, most people will start gasping for air through their mouths in the middle of a long run,  but this only makes matters worse.

Eat and Run: My Unlikely Journey to Ultramarathon Greatness: Jurek, Scott,  Friedman, Steve: 8601421057493: Amazon.com: Books


Scott Jurek is one of the most dominant ultramarathon runners in the world, winning many of the sport’s prestigious race events multiple times. He won the 100-mile Western States Endurance Run seven consecutive times. In his memoir “Eat and Run” he says: “One of the most important things you can do … is to breathe abdominally, and a good way to learn that skill is to practice nasal breathing.”

The Tarahumara native Indians of Mexico are able to run up to 62 miles a day, twice that of a typical elite athlete. Studies of the Tarahumara show that they breathe almost entirely through the nose. The tarahumara are better able to utilize nasal nitric oxide, and have more CO2 in the lungs.

Of course there are other factors that allow them to accomplish such impressive feats of endurance, but this is an excellent display of nasal breathing during athletic performance.

Anthropologist Wade Davis has studied and lived with fifteen groups of indigenous people, including tribal hunters of the Amazon. While staying with the tribe, Davis was allowed to accompany them on hunting expeditions. Hunts began in the morning and they would persistently chase animals at a jogging and running pace over many hours, possibly even days. After a while the animal would collapse from exhaustion and they would kill it at short range. Davis was most impressed by the fact that the hunters never opened their mouths to breath during the excursion. 

While you may have been told in gym class that you should breathe in through your nose and out through your mouth while exercising, it’s best to inhale and exhale through the nose for more controlled breathing that lessens the volume of air you take in and out. There are some exceptions where you’d want to breathe through the mouth like very high intensity training, but in most cases nasal breathing is the best option. 

To maintain proper carbon dioxide levels and better facilitate the oxygenation of the body, you’ll want to lower the volume of air you take in and out over time. What that means is while taking deep breaths can be good, taking deep breaths quickly is not. Some well meaning yoga instructors may teach that you should take deep breaths that expand the lungs, but fail to stress the importance of having the breath be slow and controlled.  

In The Hathapradīpikạ, a seminal text of Hatha yoga, compiled in the 15th century, one of the passages says:.


Just as lions, elephants and tigers are calm and controlled, the breath must be controlled by slow degrees. Hasty or forceful breath kills the practiser himself.” 

In the animal world, mouth breathing is a rarity to the extent that it is usually a sign of illness. Farmers know this; they will immediately know if an animal is sick not by noticing whether it breathes through the mouth. Aside from dogs, who pant to regulate their body temperature when they’re hot, most all land mammals breathe regularly through their nose except in times of distress. 

In humans, chronic mouth breathing can lead to cavities, gum disease, lowered immune function, digestive disturbances, poor sleep quality, and  can result in crooked teeth and even poorly developed facial structure.  


“During the 1960s, dentist Egil Harvold conducted a number of experiments where young monkeys’ noses were blocked with silicone nose plugs. 

This caused these monkeys to breathe through the mouth and they gradually acquired a facial appearance different from the control monkeys. The mouth-breathing monkeys developed crooked teeth, a lowered chin and other facial deformities.


Essentially mouth breathing leads to a longer face with a set back jaw, less pronounced cheekbones and restricted airways.

I’ve sometimes wondered why most athletes usually tend to be pretty good looking. I figured there would be an equal amount of facially challenged athletes as there are attractive ones.

Top 15 Most Handsome Athletes in the world 2020: Checkout!

Patrick McKeown argues that breathing plays a role here too. Because the athletes had been breathing properly, it set them up for better physical conditioning as a child meaning better sports performance, and proper breathing supports the development of good facial structure. 

Now I’ve covered only some of the important aspects of nasal breathing, Check out the book The Oxygen Advantage for an impressively thorough exploration of this topic. But I’ll leave you with one important tip to help get the most out of your breathing. Just put some micropore tape on your mouth when you sleep. As weird and slightly scary as that may sound, the quality of sleep you get from ensuring that you breathe through your nose, will definitely be worth getting used to the tape. This has helped me personally, and even people with asthma report that this drastically improves their quality of their sleep. Of courcse it’s best to avoid this if you have certain medical conditions, or in certain situations like after drinking alcohol. After wearing the tape for about 3 months, it should have you naturally breathing through your nose during sleep and improve your breathing pattern during day. 

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