NASAL breathing is a vital yet often overlooked function with profound
impacts on overall health.
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The nose performs around 30 essential functions for the body, I have
summarised them below...
8min read (grab a cuppa!)
Everyday Performance
Helps to induce relaxation
Nasal breathing provides resistance to slow down the breathing rate. The nasal passages are smaller than the mouth, which means that air has to pass through more slowly. This creates a natural resistance that helps to regulate the breathing rate and promote relaxation.
Improve cognitive function
People with normal function of the nose have improved cognitive function and energy levels in comparison to people with chronic nasal issues. In a study of 100 people to investigate cognitive function (50 with chronic rhinosinusitis) people with nasal congestion were found to have significantly more cognitive dysfunction and fatigue and had worse reaction times on computerized testing.
Smell and Partner Choice
The sense of smell is important in choosing both human and animal mates. Two people with very similar genetic make up could be related, and in-breeding increases the risk of unfavourable genes passed down from one generation to another. In relation to its influence on partner selection, scientists discovered that signals are picked up via smell, otherwise fancily referred to as olfaction. The influence of body odour in mate selection was confirmed in experiments by Wedekind in 1975. Findings show that women prefer the odour of men who are dissimilar to themselves.
Increased Visuospatial Awareness
In 2019, researchers at the Weizmann Institute in Israel suggested that nasal inhalation could be linked to cognition as part of an evolutionary survival mechanism. A sense of smell is, after all, equated with sniffing out danger. For our distant ancestors, this meant accurately assessing their surroundings to make life-or-death decisions. The Weizmann team theorized that this ancient sensory system might benefit from nasal inhalation and that, in modern life and competitive sports, nasal inhalation might automatically trigger conditions in the brain that optimise visuospatial focus. They demonstrated that nasal breathing synchronized electrical activity in the brain on a wavelength that helped to maximize visuospatial awareness.
Mediates Olfactory-induced Behavioural response
​The sense of smell, a primary function of the nose, plays a significant role in aiding behavioural response by activating the amygdala and the hippocampus. The amygdala is responsible for the emotional processing of odorant molecules, with odours being able to serve as rewards or punishments in the associative learning process. This means that odours associated with positive states reinforce behaviours that lead to more of the positive state and vice versa for the negative states. Brain imaging studies have found that activation of the amygdala correlates with pleasant and unpleasant odours, reflecting the link between odours and emotions. The hippocampus, which is also closely linked to the sense of smell, assists with the learning process and is associated with episodic memory. This is where an odour can lead to the retrieval of a memory from a specific point in time or place, highlighting the complex interplay between the sense of smell, emotion, and our cognitive processes. You might have experienced a time when a particular scent brought you back to some event years ago. The nose and its functions shape our behaviour, memory, and emotional responses.
Reduced Vocal Effort
Professional singers engage in prolonged periods of breathing through the mouth. This increases the minimum pressure required to initiate and sustain vocal fold oscillation. Compared to oral breathing, nasal breathing can naturally humidify and filter incoming air. This can help to prevent irritation and inflammation of the vocal cords, leading to improved voice quality and a lower risk of developing voice disorders. Therefore, breathing through the nose can help reduce the vocal effort required during speech. It is important for singers to maintain nasal breathing during their everyday life, including exercise, rest and sleep. Breathing through the nose helps to prevent dryness of the larynx.
Nasal Resonance
The nose plays a crucial role in speech by creating nasal resonance. This occurs when sound waves from the vocal cords resonate in the nasal cavity, producing a unique quality to the voice. Without the nose, the voice would sound monotone and lack depth. Additionally, nasal resonance helps to add emphasis and nuance to our speech, allowing us to communicate effectively with others. Conversely, too much nasal resonance decreases speech intelligibility and impairs social interaction.
Breathing and the nose
Improves recruitment of the diaphragm breathing muscle
The diaphragm which separates the chest from the abdomen is the main breathing muscle. Breathing through the mouth causes reduced movement of the diaphragm.
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Conversely, breathing through the nose increases recruitment of the diaphragm. For persons with upper chest breathing, switching to habitual nasal breathing is important in rehabilitation.
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This is relevant to all modalities (physiotherapy, physical therapy, yoga, Pilates etc.) working with the biomechanical dimension of breathing.
​Increases Oxygen Uptake in the Blood
Nose breathing is more effective at increasing oxygen uptake than breathing through the mouth. When our nose is blocked, the oxygen uptake in the blood reduces.
 In a study of individuals who continuously breathe through their noses, arterial pressure of oxygen increased by nearly 10%.
Production of Nitric Oxide
The nose produces a molecule known as nitric oxide, which plays a role in maintaining healthy lung function and may help to protect against certain respiratory infections.
Dilation of blood vessels in the lungs
Breathing through the nose helps dilate blood vessels in the lungs and improves arterial oxygenation compared with oral breathing.
Redistribution of blood throughout the lungs
The transition of human beings to standing upright would have negatively impacted gas exchange in the upper regions of the lungs. By breathing through the nose, nitric oxide redistributes blood throughout the lungs increasing blood flow by as much as 24% in the upper regions. It is thought that nitric oxide from the nose could have emerged in bipedal mammals not only to improve oxygen transfer from the lungs to the blood but also to protect the body against infection.
Defence Against Inhaled Pathogens
Another crucial function of the nose is to act as a line of defence against inhaled pathogens. When we breathe, the air passes through the nasal passages, lined with mucus, hairs, and immune cells. These mechanisms help to trap and remove harmful particles, such as bacteria and viruses, from the air we breathe, preventing them from entering the lungs.Â
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The nose plays a critical role in the chemical inactivation of pathogens. The nasal cavity contains enzymes and other chemical agents that can destroy harmful substances before they enter the respiratory system. For example, lysozyme is an enzyme found in the nasal mucus that can break down the cell walls of bacteria, rendering them harmless.
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This chemical defence mechanism is essential to our body’s immune system, helping protect us from various airborne threats. Breathing through the nose harnesses the gas nitric oxide, which is produced in the paranasal sinuses. Higher levels of nitric oxide is associated with fewer cold symptoms and airway infection following periods of stress in daily life.
Helping maintain elasticity of the lungs
Maurice Cottle, a renowned rhinologist, includes among the functions of nasal breathing: Breathing through the nose imposes a resistance to both inspiration and expiration which in turn helps to maintain normal elasticity of the lungs, thus ensuring optimal conditions for gas exchange.
Warming
The nose plays a vital role in thermoregulation, or the body’s ability to maintain its core temperature within a specific range. The nasal passages are filled with blood vessels that help dissipate heat from the body.
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As we inhale, the air passing through the nose is warmed by these blood vessels, helping to regulate our body temperature. The nose can also help prevent overheating in hot environments by increasing blood flow to the skin.
Humidification of incoming air
The major function of the nose is to humidify air before it reaches the lungs for gas exchange. Conditioning of inspired air is achieved through evaporation of water from the internal surface of the nasal airway. Drawing moist and warm air helps to protect the lungs from drying out and becoming inflamed.
Water balance
The nose helps regulate water balance in the body by conserving water during exhalation. The air we breathe contains moisture from our respiratory tract as we exhale. The nasal mucosa helps to capture and recycle this moisture, reducing water loss from the body.
Nose breathing for improved sleep quality
Important for Deeper Sleep Quality
The nose is necessary for proper nasal breathing, which has been shown to contribute to deeper and more restful sleep. This is because breathing through the nose reduces the severity of snoring and obstructive sleep apnoea. It is important to wake up with a moist mouth in the morning which is an indicator of nasal breathing during sleep.
Smell and taste
Smelling
Humans have approximately 450 types of olfactory receptors. The nose is a complex and multifaceted organ that performs various critical functions. Its most well-known function is the sense of smell, or olfaction, which involves detecting and processing odorant molecules in the air. This intricate process involves a series of receptors and nerve pathways that allow us to distinguish between countless scents, from pleasant aromas to unpleasant odours.
Sense of smell as a test for neurological injury
The sense of smell is a sensitive test for neurological injury associated with traumatic brain injury (TBI). Impaired ability to smell was the most common neurological deficits, found in 65 veterans.
Taste perception
Although this might sound counterintuitive since the nose is for smell and the mouth for taste, the nose plays a crucial role in accurately tasting things. This is because the nose communicates with a part of the brain responsible for taste perception called the orbitofrontal cortex. This brain centre receives taste and smell signals and processes them together, coupling smell and taste. This pairing enhances the flavours of our food and beverages, making them much more appetizing. When our sense of smell is impaired due to a common cold or other condition, it affects our ability to perceive flavours, resulting in a less flavourful experience. Additionally, the orbitofrontal cortex is responsible for odour perception and discrimination, creating a spatial odour map to recognize specific odours. Thus, the nose plays a crucial role in our ability to taste.
Nose breathing for asthma, rhinitis and hayfever
​Important in the Control of Allergic Rhinitis
Allergic rhinitis, commonly known as hay fever, is a condition that affects millions of people worldwide. It is an allergic reaction to environmental triggers, such as pollen, dust, or animal dander. Symptoms of allergic rhinitis include sneezing, a runny nose, itchy eyes, and nasal congestion. The nose plays a vital role in controlling allergic rhinitis, as it acts as a filter, trapping allergens before they can enter the respiratory system. Additionally, the nasal passages produce mucus, which can help remove allergens from the body. Proper management of allergic rhinitis can significantly improve quality of life, and the nose plays a crucial role in achieving this goal.
Important in the Control of Asthma
Asthma is characterized by inflammation and narrowing of the airways, which can lead to breathing difficulties and other symptoms. Studies have shown that nasal breathing can help reduce the severity and frequency of asthma symptoms, mainly if triggered during exercise. Additionally, some asthma medications are delivered through the nose, highlighting their importance in managing this condition.
Nasal Dilation
The nose can dilate, or open wider, to allow for increased airflow during exercise or stress. This is a natural response to increased demand for oxygen and helps to ensure that the body receives enough oxygen during periods of exertion.
During physical exercise
Breathing through the nose during exercise helps decongest the nose
Nasal resistance decreases linearly as expired CO2 levels and exercise levels increase. The constant relationship between nasal resistance and minute ventilation during hypercapnia and exercise suggests that nasal resistance is regulated by the respiratory centre to match the level of respiratory demand.
Helps prevent exercise induced bronchoconstriction
Breathing through the nose during physical exercise markedly reduced post exercise airway narrowing as compared to breathing through the mouth. This is relevant to all persons, whether diagnosed with asthma or not.
Better utilisation of oxygen during exerciseÂ
Breathing through the nose during physical exercise reduces the pressure of oxygen expired from the body. This indicates that breathing through the nose is more efficient at extracting O2 from the lungs and blood to be used by the working muscles.
Physical Training with Nasal breathing Reduces ventilation
At first, when one switches to breathing through the nose during exercise, the sensation of air hunger is strong. With sustained practise of nasal breathing during exercise, the body adapts to a higher tolerance to the accumulation of carbon dioxide. This is in turn leads to a reduction in ventilation, leading to reduced breathlessness and greater economy.
If that's not enough reasons to switch to nasal breathing, I don't know what is!!
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