Are We Raising a Generation of Mouth Breathers?
- May 8
- 11 min read
Updated: May 14
Alicia Lewis is a registered dental hygienist, myofunctional therapist, and founder of Paradigm Dental Therapy in London, Ontario. With over 25 years of experience, she specializes in airway-focused care, breathing, and functional oral health to support lifelong wellness.
For many parents, an open-mouth posture, a snoring child, dark under-eye circles, or crowded teeth may seem relatively normal. In today’s world, these signs are so common that they often go unnoticed. But growing research suggests these symptoms may not be “normal” at all.
Instead, they may reflect a widespread and increasing problem affecting modern children and adults alike: chronic mouth breathing. What was once considered a harmless habit is now being linked to disrupted sleep, altered facial growth, behavioral concerns, poor concentration, airway dysfunction, and long-term health consequences.
The question many airway-focused professionals are beginning to ask is this: Are we raising a generation of mouth breathers?
Breathing: The foundation we rarely think about
Breathing is automatic, yet the way we breathe matters profoundly. The human body was designed primarily for nasal breathing. The nose filters, humidifies, warms, and pressurizes air while also helping regulate oxygen uptake and nitric oxide production, all critical for healthy sleep, nervous system regulation, and overall wellness.
Chronic mouth breathing bypasses many of these important functions. According to a review published in Frontiers in Public Health, “Normal respiratory function of the nose is essential for the balanced growth of craniofacial structures.”[1]
While occasional mouth breathing during illness or exercise is normal, habitual mouth breathing, especially during childhood, may significantly influence how the face, jaws, airway, and oral structures develop over time. However, even during periods of congestion, physical exertion, or recovery from illness, the body can benefit from learning more efficient breathing patterns through targeted breathing retraining and myofunctional therapy.
Importantly, this is not about eliminating natural mouth breathing when it is needed but rather improving the body’s ability to return to efficient nasal breathing as the default state whenever possible.
From a physiological perspective, nasal breathing plays a key role in optimizing airway function. The nasal passages contribute to air filtration, humidification, and the production of nitric oxide, a molecule that supports vascular tone and oxygen delivery. Research has shown that nasal breathing produces significantly higher levels of nitric oxide compared to mouth breathing, which may enhance respiratory efficiency and circulation. In a controlled physiological study, nasal breathing resulted in significantly greater exhaled nitric oxide compared to mouth breathing, highlighting the functional advantage of nasal respiration in normal conditions.[2]
During exercise, breathing patterns also influence efficiency and respiratory load. A 2024 study published in Frontiers in Physiology found that nasal breathing may improve ventilatory efficiency compared to oral breathing, supporting more economical oxygen utilization and potentially reducing respiratory strain during physical activity.[3]
These findings support the idea that while mouth breathing is sometimes necessary, it is not the most physiologically efficient default pattern. Over time, habitual reliance on oral breathing may reduce respiratory efficiency and reinforce dysfunctional patterns in posture, tongue position, and airway stability.
This is where myofunctional therapy and breathing retraining become clinically relevant. Rather than simply discouraging mouth breathing, these approaches aim to restore functional breathing capacity by improving nasal breathing tolerance, diaphragmatic breathing coordination, and orofacial muscle function. The goal is not restriction, but adaptability, ensuring that the body can efficiently use nasal breathing at rest, during sleep, and during submaximal activity, while still appropriately using oral breathing when physiologically required.
In this way, breathing retraining supports both performance and long-term health by helping individuals return to a more efficient, neurologically integrated breathing pattern that aligns with optimal airway function.
Modern habits are changing facial development
Researchers are increasingly exploring how environmental and lifestyle factors may be influencing craniofacial growth patterns in children. Today's children are experiencing a range of factors that could impact their development, including:
Increased allergies and nasal congestion
More ultra-processed, softer diets
Higher screen time and forward-head posture
Reduced breastfeeding rates in some populations
Chronic stress and poor-quality sleep
Less chewing demand on developing jaws
Increased prevalence of airway obstruction
These factors can contribute to dysfunctional breathing patterns and altered oral posture, which may have long-term effects on both oral and overall health. Addressing these issues early is crucial for promoting proper development and preventing future complications.
A systematic review and meta-analysis published in BMC Oral Health found that mouth breathing in children was associated with measurable changes in facial skeletal development. Researchers noted findings including:
Narrow upper arches
Increased facial height
Backward rotation of the jaws
Steeper occlusal planes
Airway narrowing [4]
The review concluded, “Airway stenosis was common in mouth-breathing children.” [4] This matters because the position of the tongue, lips, jaws, and airway all work together during growth and development.
When the mouth remains open habitually, the tongue often fails to rest against the palate, which is its natural position for supporting the proper development of the upper jaw. This misalignment can have significant long-term effects on both oral and facial development. Over time, the lack of tongue support can contribute to a range of issues, starting with crowded teeth, as the teeth do not have the proper guidance to align correctly.
A narrow palate is another common consequence, as the tongue plays a crucial role in helping to widen and shape the roof of the mouth. Without the tongue's upward pressure against the palate, the upper jaw may fail to develop properly, leading to constricted arches. This can result in recessed jaws, where the lower jaw may also fail to develop forward, causing an imbalance in facial structure.
In addition to these dental and structural changes, poor facial symmetry may emerge, as the lack of proper tongue posture can affect the balance of the face. One of the more concerning issues that can arise from habitual mouth breathing is airway restriction. As the upper jaw narrows, it can reduce the space available for the airway, leading to breathing difficulties. This can result in sleep-disordered breathing, including conditions like snoring or even obstructive sleep apnea, which disrupts sleep quality and has long-term health implications. Addressing the root cause of mouth breathing early on can help prevent these issues and support healthier development.
The link between mouth breathing and brain development
One of the most concerning aspects of chronic mouth breathing is its potential impact on sleep quality, which in turn affects a child’s neurological development. Children rely on deep, restorative sleep to support a wide range of crucial functions. One of the most important roles of quality sleep is memory consolidation, where the brain processes and stores new information learned throughout the day. This is vital for academic success and overall cognitive growth.
Sleep also plays a significant role in emotional regulation. Adequate rest helps children manage their emotions and reactions to stress, contributing to better mental health and well-being. Additionally, sleep supports hormonal balance, ensuring that growth hormones and other vital hormones are properly regulated, which is essential for healthy physical development.
Moreover, sleep is integral to growth and repair, as the body uses this time to heal and restore itself. This includes cellular repair and the strengthening of the immune system, which are essential for a child’s overall health. Sleep also supports cognitive processing, enhancing a child’s ability to think critically, solve problems, and process new experiences. Finally, restorative sleep is crucial for behavioral development, as it helps children develop the self-control and coping mechanisms necessary for positive social interactions and healthy emotional responses. Chronic mouth breathing, which often disrupts sleep quality, can therefore have long-lasting effects on a child’s physical, emotional, and cognitive development.
But mouth breathing is often associated with disrupted sleep and sleep-disordered breathing.
Research examining preschool-aged children found that better sleep quality was associated with improved cognitive and behavioral outcomes.[5]
Many children with chronic mouth breathing may not exhibit the typical signs of tiredness, such as yawning or falling asleep during the day. Instead, they may present with a range of behavioral and emotional challenges that can be perplexing for parents. Hyperactivity is one common symptom, where children seem overly energetic or restless, often leading to difficulties in maintaining focus. This can be accompanied by emotional dysregulation, where children have trouble managing their emotions, leading to frequent outbursts or mood swings.
Anxiety and irritability are also common in children with chronic mouth breathing, as the poor sleep quality associated with airway dysfunction can lead to heightened stress and discomfort. Bedwetting may also be observed, particularly in children who have trouble achieving restorative sleep due to airway issues. Other behavioral challenges, such as tantrums or oppositional behavior, can arise as well, often making it difficult for parents to understand the root cause of these actions.
Additionally, learning difficulties may surface, with children struggling to concentrate or process information effectively, which is often a result of ongoing sleep disturbances. Parents are frequently surprised to learn that these behavioral concerns, which may have seemed unrelated to sleep, are often connected to poor sleep quality and underlying airway dysfunction. Addressing these issues early on can help improve both sleep and behavior, leading to better overall health and well-being.
The “long face” pattern and airway changes
Airway-focused dentists and orthodontists often observe distinct patterns in children and adults who suffer from chronic mouth breathing. These patterns are typically linked to the dysfunction of the airway and can manifest in various physical features. One common sign is an elongated facial appearance, where the face may appear more vertically stretched due to improper tongue posture and mouth breathing.
Other noticeable signs include dark under-eye circles, which are often associated with poor sleep quality resulting from airway obstruction. Additionally, individuals may exhibit a poor lip seal, as the mouth is often left open to compensate for restricted airflow through the nose. Forward head posture is another pattern commonly observed, where the head protrudes forward in an attempt to open the airway, causing strain on the neck and spine.
Narrow dental arches are also frequently seen in patients with chronic mouth breathing, as the tongue does not rest against the roof of the mouth to help shape the arches. A recessed chin is another feature that can result from these breathing patterns, as the lower jaw may not develop properly. Finally, crowded teeth are a common issue, as a lack of tongue pressure on the roof of the mouth can contribute to misalignment of the teeth. Recognizing these patterns early on can help guide treatment options to improve both airway health and facial development.
A clinical review discussing mouth breathing and facial growth noted that children with chronic mouth breathing may develop what is often referred to as an “adenoid face,” characterized by narrow arches, altered jaw posture, and increased facial height.[4]
An article featuring airway-focused experts explained, “The tongue naturally fills your palate space.” Without appropriate tongue posture against the palate, facial growth patterns may shift downward rather than outward and forward.
This is not merely cosmetic. Facial structure and airway development are closely interconnected.
Smaller jaws and narrower palates may leave less room for the tongue and airway, increasing the likelihood of sleep-disordered breathing later in life.
Mouth breathing doesn’t only affect children
While the growth years are especially important, adults are not immune to the effects of dysfunctional breathing. Many adults who mouth breathe experience a range of symptoms, including chronic fatigue, dry mouth, poor sleep quality, brain fog, TMJ tension, neck pain, snoring, and sleep apnea symptoms.
Some adults may have unknowingly breathed through their mouths for decades, while others develop the habit later in life due to factors such as chronic congestion, allergies, stress, airway obstruction, poor oral posture, or untreated sleep-disordered breathing.
What many people discover is that breathing dysfunction affects far more than just sleep. It can also influence energy levels, mood, posture, exercise tolerance, cognitive performance, and nervous system regulation. Addressing dysfunctional breathing is crucial for improving overall health and well-being.
Why awareness is growing
For decades, airway health and oral function were often overlooked in mainstream healthcare discussions. However, a significant shift is taking place as healthcare professionals across various fields, dentists, orthodontists, ENTs, sleep physicians, lactation consultants, myofunctional therapists, and functional healthcare practitioners, are coming together to focus on prevention and early intervention. This collaboration is driving a much-needed conversation about the importance of airway health and its impact on overall wellness.
As a result, parents are starting to ask deeper, more informed questions about their children’s health. Many are wondering why crowded teeth have become so common, raising concerns about the factors contributing to dental misalignment. Others are questioning why so many children are struggling with sleep, with sleep disturbances affecting their daily functioning and well-being. There are also growing concerns about snoring and mouth breathing, which have become prevalent in children and are linked to various health issues. Furthermore, parents are increasingly asking why fatigue and anxiety seem to be affecting so many young people today.
The answer to these questions is complex and multifactorial, but airway health is emerging as a crucial piece of the puzzle. Early intervention and addressing airway health can have a profound impact on a child’s overall development, health, and quality of life. By focusing on airway health from a young age, we can help prevent many of these issues and support children in thriving physically and emotionally.
How myofunctional therapy is changing lifelong wellness
Myofunctional therapy is a unique approach that focuses on improving the function of the tongue, lips, cheeks, jaw muscles, and breathing patterns. Rather than simply addressing symptoms, the therapy targets the root causes of dysfunction in various aspects of oral and respiratory health. One of the primary areas it addresses is tongue posture, ensuring that the tongue is positioned correctly in the mouth to support optimal function. Additionally, myofunctional therapy promotes nasal breathing, which plays a crucial role in proper oxygen intake and overall health.
Another key focus of the therapy is oral muscle tone, as strengthening the muscles of the mouth can contribute to better oral function and support the stability of orthodontic treatments. Swallowing patterns are also examined to ensure that they are efficient and beneficial for long-term health. Proper lip seal is encouraged to prevent mouth breathing, which can have a range of negative impacts on oral health and development. Airway stability is another important aspect of myofunctional therapy, as it helps ensure the airway remains open, allowing for proper breathing and preventing issues like snoring.
By addressing these foundational elements, myofunctional therapy can support several improvements in overall wellness. Among the benefits are improved nasal breathing, which enhances oxygenation and promotes better sleep quality. Therapy may also reduce snoring, leading to more restful nights. Better oral function, including enhanced swallowing and chewing, supports not only dental health but also orthodontic stability. In addition, the therapy encourages healthier facial development, which can impact facial aesthetics and function. Lastly, myofunctional therapy fosters increased awareness of breathing habits, empowering individuals to adopt more conscious and healthier habits that benefit their long-term wellness.
Importantly, myofunctional therapy is often part of a collaborative approach and may be combined with airway evaluation, orthodontic care, ENT assessment, or sleep treatment when appropriate. As awareness grows, many families are realizing that breathing well is not a luxury, it is foundational to lifelong health. Mouth breathing is not simply a cosmetic issue or harmless childhood habit.
It may be an early sign that the body is struggling to breathe efficiently during both wakefulness and sleep. The encouraging news is that awareness, education, and early intervention can make a profound difference. Because when children breathe better, they often sleep better. When they sleep better, they learn better. When breathing function improves early, the benefits may last a lifetime.
Read more from Alicia Lewis
Alicia Lewis, Entrepreneur, Educator, RDH, MFT
Alicia Lewis is a registered dental hygienist and myofunctional therapist with more than 25 years of experience in oral health, airway function, and patient-centered care. As the founder of Paradigm Dental Therapy in London, she is passionate about helping patients and professionals understand the connection between breathing, oral function, and overall wellness. Her work blends clinical expertise, education, and functional therapy to support lasting health outcomes. Through her writing and teaching, Alicia empowers readers with practical insights that transform the way they view dental care and whole-body health.
References:
[1] Lin L, Zhao T, Qin D, Hua F, and He H (2022). The impact of mouth breathing on dentofacial development: A concise review. Front. Public Health 10:929165. doi: 10.3389/fpubh.2022.929165
[2] B Kimberly, B Nejadnik, G. D. Giraud, W. E. Holden, Nasal Contribution to Exhaled Nitric Oxide at Rest and During Breathholding in Humans, American Journal of Respiratory and Critical Care Medicine, Volume 153, Issue 2, February 1996, Pages 829-836,
[3] Eser P, Calamai P, Kalberer A, Stuetz L, Huber S, Kaesermann D, Guler S and Wilhelm M (2024) Improved exercise ventilatory efficiency with nasal compared to oral breathing in cardiac patients. Front. Physiol. 15:1380562. doi: 10.3389/fphys.2024.1380562
[4] Zhao, Z., Zheng, L., Huang, X. et al. Effects of mouth breathing on facial skeletal development in children: a systematic review and meta-analysis. BMC Oral Health 21, 108 (2021).
[5] Reynaud, E., Vecchierini, M.F., Heude, B., Charles, M.A. and Plancoulaine, S. (2018), Sleep and its relation to cognition and behaviour in preschool-aged children of the general population: a systematic review. J Sleep Res, 27: e12636.
