Science of Breathing

17.01.2021 |

Episode #4 of the course Breathwork: Science and practice by David Urbansky


Today is all about the air you breathe. What is “air” anyway and how should you consume it? Do you know this feeling when you have a meal in front of you and you can’t decide whether to use a spoon or a fork to eat? The same decision can be made when breathing air, do you use your mouth or nose to “eat” your air? Let’s find out answers to those weird questions!


As we learned in the last lesson, the core of breathing is the gas exchange, oxygen in, carbon dioxide out. There is also nitric oxide involved if you breathe correctly. Let us look at these three gases a bit closer!

Oxygen – O2. Your body likes to use O2 as a source to metabolize sugars, fats, and proteins for energy. This is called aerobic metabolism and it is your body’s default mechanism to retrieve energy. If, however, you exercise really hard and your lungs can’t keep up with your muscles’ demand for oxygen, your body can switch to anaerobic metabolism, that is, energy creation without oxygen! This form of metabolization is 16 times less effective than with oxygen and lactic acid is produced, degrading your muscles’ effectiveness and leading to muscle soreness later on.

Carbon Dioxide – CO2. Carbon dioxide is in the news all the time because it contributes to global warming. And while it is also a waste product of your breathing, it is necessary to regulate your breathing and your body’s PH level. By default, your blood has a saturation of above 95% oxygen, but more is not necessarily better. If you get your blood oxygen saturation to 100%, your body cannot extract the oxygen from the blood as it needs a certain amount of CO2 to do so. This is also why you feel dizzy when you take too many fast deep breaths (hyperventilate) and is called the “Bohr Effect,” which was discovered by Niels Bohr’s father, Christian Bohr.

Nitric Oxide – NO. When breathing through your nose, this beneficial gas reaches your lungs and bloodstream. This gas is good for your blood vessel health [1], boosts the oxygen levels in your blood, has shown to be antibacterial and antifungal [2, 3], and improves immunologic responses against toxins [4, 5].


Breath through Your Nose, Not Your Mouth!

Breathing during the day is usually automatic, meaning you don’t have to concentrate on it. One thing you should definitely make sure though is that you always breathe through your nose and not your mouth.

The nose has the first contact with incoming air and provides an important set of services:

• It heats or cools incoming air [6]. On cold days, the air arrives at the lungs at nearly body temperature, protecting airways against inflammation and irritation. Studies have shown that when people breathe in dry cold air through the mouth, they can suffer from exercise-induced bronchoconstriction [7].

• It humidifies and purifies the air [6]. Your nose is also your line of defense against dust, viruses, bacteria, and anything else floating in the air that should not get into your lungs.

• It slows down airflow allowing for more effective gas exchange [8, 9] with up to 20% better oxygen uptake. When exhaling through the nose, you create a back pressure that lets air out slower, so don’t just in but also exhale through your nose.

• Studies have shown that nose-breathing also improves your cognitive function like learning and remembering by stimulating certain areas in your brain [8].

• Your body produces nitric oxide (NO) in your nasal cavities and you have learned at the beginning of this lesson how beneficial that is.

And if these arguments are not enough to shut your trap, here are some reasons why mouth breathing is bad for you:

• It dehydrates you [9] as water vapor is escaping through your open mouth. Ever woke up with a dry mouth in the morning feeling thirsty?

• It causes snoring and sleep apnoea [10] and other sleep-related sleeping disorders due to nasal respiratory obstruction [4, 5].

• When growing up as a child, it hinders the growth and development of the central nervous system and has a negative effect on memory and learning capabilities [6].

• It causes forward head posture [11, 12, 13, 14].

• You take in too much air which is called over-breathing. Constant over-breathing, or hyperventilating, is bad since it has profound effects on the O2/CO2 ratio, which you will learn more about later.

If you stop reading this course here, you have already learned a super valuable thing that will change your life for the better, and that is that you should always breathe through your nose. Continue reading to learn so much more!

Tomorrow, we get practical. I’ll show you a couple of tests so you can see how well your breathing “performs” at this point. From there, you can apply breathwork that you’ll learn throughout the rest of this course to become better.

See you tomorrow!


Recommended book

The Breathing Book by Donna Farhi



[1] Nitric oxide and the paranasal sinuses

[2] Strong humming for one hour daily to terminate chronic rhinosinusitis in four days: a case report and hypothesis for action by stimulation of endogenous nasal nitric oxide production

[3] Nasal nitric oxide in man

[4] Mathematical analysis and digital simulation of the respiratory control system

[5] A breathing model of the respiratory

[6] Influences of mouth breathing on memory and learning ability in growing rats

[7] The nasal response to exercise and exercise induced bronchoconstriction in normal and asthmatic subjects

[8] Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function

[9] Air-conditioning in the human nasal cavity

[10] How Does Open Mouth Breathing Influence Upper Airway Anatomy

[11] Mouth breathing and forward head posture: effects on respiratory biomechanics and exercise capacity in children

[12] Relationship between mouth breathing and postural alterations of children: a descriptive analysis

[13] Exercise capacity, respiratory mechanics and posture in mouth breathers

[14] Assessment of the body posture of mouth-breathing children and adolescents


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