Are We Raising a Generation of Mouth Breathers?
- 6 days ago
- 7 min read
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 rests low instead of against the palate, where it naturally supports the widening and forward development of the upper jaw. Over time, this may contribute to:
Crowded teeth
Narrow palates
Recessed jaws
Poor facial symmetry
Airway restriction
Sleep-disordered breathing
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 and neurological development. Children need deep, restorative sleep for:
Memory consolidation
Emotional regulation
Hormonal balance
Growth and repair
Cognitive processing
Behavioral 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 appear tired in the traditional sense. Instead, they may present with:
Hyperactivity
Difficulty focusing
Emotional dysregulation
Anxiety
Irritability
Bedwetting
Behavioral challenges
Learning difficulties
Parents are often surprised to discover that what appeared to be behavioral concerns may be connected to poor sleep quality and airway dysfunction.
The “long face” pattern and airway changes
Airway-focused dentists and orthodontists frequently recognize patterns associated with chronic mouth breathing. These patterns may include:
Elongated facial appearance
Dark under-eye circles
Poor lip seal
Forward head posture
Narrow dental arches
Recessed chin
Crowded teeth
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 shift is happening as collaboration between various healthcare professionals, including dentists, orthodontists, ENTs, sleep physicians, lactation consultants, myofunctional therapists, and functional healthcare practitioners, is now driving a conversation focused on prevention and early intervention.
As a result, parents are beginning to ask deeper questions, such as:
Why are crowded teeth so common?
Why are so many children struggling with sleep?
Why do so many kids snore or mouth breathe?
Why are fatigue and anxiety becoming increasingly prevalent?
The answer to these concerns is complex and multifactorial, but airway health is emerging as an essential piece of the puzzle. Addressing this aspect early on can significantly improve overall health and well-being, particularly for children.
How myofunctional therapy is changing lifelong wellness
Myofunctional therapy focuses on improving the function of the tongue, lips, cheeks, jaw muscles, and breathing patterns. Rather than focusing solely on symptoms, myofunctional therapy aims to address underlying dysfunctions related to:
Tongue posture
Nasal breathing
Oral muscle tone
Swallowing patterns
Lip seal
Airway stability
Therapy may support:
Improved nasal breathing
Better sleep quality
Reduced snoring
Enhanced oral function
Orthodontic stability
Healthier facial development
Increased awareness of breathing habits
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.
