Body processes

Nose and mouth breathing – function, task and diseases

Nasal and mouth breathing

Nose and mouth breathing both serve the purpose of breathing , but differ in their physiological process. Nasal breathing involves inhaling and exhaling through the nose . With mouth breathing, on the other hand, the air is guided through the oral cavity into the other airways .

What is nose and mouth breathing?

Nasal breathing is physiological breathing. This means that a healthy person breathes in and out through their nose when they are at rest. If there is an increased need for oxygen and therefore air for breathing, eg during physical activity, breathing through the mouth can also be physiological. Causes of permanent and thus pathological mouth breathing include polyps , colds, misaligned teeth and jaws, allergies or an incorrect tongue resting position.

When breathing through the nose, air is drawn in through the nostrils and directed into the nasal passages. It slides along the turbinates and then passes through the pharynx into the trachea , the bronchi and finally into the lungs . This is where the gas exchange takes place. The exhaled air mixed with carbon dioxide passes through the bronchi and trachea through the throat into the nasal passages and is then exhaled through the nostrils. Nasal breathing is usually done with the mouth closed.

When the body is at rest, breathing does not take place through both nostrils at the same time. The nostrils are alternately flown through with more or less air. so that the nostril with the reduced air flow has time to regenerate the mucous membrane. This process is also known as the nasal cycle .

With mouth breathing, the air you breathe in is drawn in through your mouth. The air is thus directly in the oral cavity, the path via the nasal passages and nasal conchae is completely left out. The remaining path of the breathing air corresponds to the path of nasal breathing. From the oral cavity, the air enters the lungs via the pharynx and the lower airways.

function & task

The physiological form of breathing in humans is nasal breathing. There are several reasons for this. The nasal cavities and the turbinates are lined with nasal mucosa . The nasal mucosa is traversed by many vessels and covered with a layer of cilia . The cilia beat in the direction of the throat about 500 times per minute. Inhaled foreign bodies and pathogens stick to the mucus layer of the mucous membrane and are then transported towards the throat by the cilia. There they are swallowed with the saliva and rendered harmless by the stomach acid . This prevents the foreign substances from getting into the lungs and, in the worst case, onecause infection .

Due to the many vessels, the mucous membrane is very well supplied with blood and therefore warm. Cold air that flows in through the nose is warmed by the mucous membrane. This protects the lungs and bronchi from excessively cold air. In addition, the mucous membranes ensure that the breathing air is humidified with every breath. Breathing through the nose also stimulates the olfactory nerve. So-called olfactory cells are embedded in the mucous membrane. When inhaling through the nose, odor molecules reach the mucous membrane and thus enable the perception of a wide variety of smells.

Another advantage of nasal breathing is that the nitrogen monoxide produced in the paranasal sinuses enters the lungs together with the air we breathe in. Nitric oxide can destroy viruses , parasites and abnormal cells in the airways and lungs. It also appears to play a role in pain perception, sleep and learning . Nitric oxide also ensures that more oxygen is released from hemoglobin in the lungs . The same applies to carbon dioxide. A high carbon dioxide content favors the absorption of oxygen in the lungs. This is known as the Bohr effect .

The nasal cavity and the paranasal sinuses belong to the so-called dead space. Carbon dioxide accumulates here. When you inhale through your nose, it is transported to your lungs. Because the air bypasses the nasal cavities when breathing through the mouth, less carbon dioxide gets into the lungs, making it more difficult for the lungs to absorb oxygen . Nose breathing leads to a 10-15% higher oxygen saturation of the blood compared to mouth breathing .

In addition, nasal breathing seems to increasingly activate the parasympathetic nervous system. The parasympathetic nervous system is part of the autonomic nervous system . It controls most of the internal organs. It dampens the heartbeat and is responsible for rest and sleep. It is therefore also referred to as the calming nerve. The antagonist of the parasympathetic nervous system is the sympathetic nervous system , the fight and flight nerve. It activates the body and stimulates the cardiovascular system . Studies have shown significantly higher sympathetic nervous system activity when breathing through the mouth.

Diseases & Ailments

A nasal breathing obstruction can have various causes. In adults, in many cases there is an enlargement of the inferior turbinate. A deviated nasal septum can also lead to obstruction of nasal breathing. Rarer reasons are polyps, tumors or injuries.

If children can no longer breathe properly through their nose, a foreign body should always be considered. Certain medications, such as some antidepressants , hypertensives, and contraceptives , can also result in obstructed nasal breathing. The same applies to long-term use of decongestant nasal drops or nasal sprays . The nasal mucosa initially swells up as a result of the drops, but as soon as the effect wears off, the vessels fill up more reactively and the swelling is even greater than before ingestion.

The most common reason for obstructed nasal breathing is rhinitis, i.e. a common cold . This can be bacterial , viral or allergic. Acute or chronic inflammation of the paranasal sinuses can also make nasal breathing so difficult that additional mouth breathing is required.

Predominant mouth breathing can lead to aerophagia . Aerophagia is an excess of air in the stomach and intestines. The result is flatulence , abdominal pain and increased belching .

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.