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The hidden dangers of mouth breathing in children: early signs every parent should know

Mouth breathing in children is often dismissed as a harmless habit. However, growing evidence highlights that this seemingly minor issue can significantly affect a child’s health, development, and academic performance.

The habit of breathing predominantly through the mouth rather than the nose bypasses essential functions provided by nasal breathing, including warming, filtering, and humidifying inhaled air. Recognising the early signs and understanding their potential implications is vital for parents seeking to safeguard their child’s developmental health. If left untreated, mouth breathing can contribute to facial growth abnormalities, dental issues, disrupted sleep, and even behavioural challenges that mimic ADHD (Lin et al., 2022; Kalaskar et al., 2021).

In our guide to how myofunctional therapy helps correct mouth breathing, we explore broader causes and solutions. Here, we focus specifically on recognising early signs and why prompt intervention is critical for your child’s lifelong wellbeing.

Why mouth breathing happens

Mouth breathing often begins due to nasal obstructions such as allergies, chronic sinus congestion, enlarged tonsils, adenoid hypertrophy, or a deviated nasal septum (Valcheva et al., 2018). These conditions restrict airflow through the nose, prompting the body to compensate by switching to the mouth for air intake. Initially, this might occur only at night or during illness, but if the obstruction is not resolved, it can quickly become a habitual pattern.

This shift from nasal to mouth breathing can be subtle and go unnoticed for a long time. Parents might not immediately recognise the behavioural and physical changes that stem from altered breathing patterns. As the child continues to rely on their mouth for breathing, it reinforces poor muscular habits around the lips, jaw, and tongue, further encouraging this dysfunctional pattern. The position of the tongue often drops to the floor of the mouth instead of resting on the palate, which is critical for healthy oral development.

Once a child develops the habit of mouth breathing, it can persist even after the original cause is resolved. This is because muscle memory, postural adaptations, and compensatory habits become ingrained. Without conscious retraining and therapeutic intervention, the child’s breathing remains altered, often becoming the default pattern. This persistent dysfunction disrupts natural facial growth and airway development, potentially leading to narrow dental arches, high palates, elongated faces, and compromised airway size (Lin et al., 2022).

Children are particularly vulnerable to these impacts because their skeletal structures are still malleable. During early childhood, the face, jaws, and airway are undergoing rapid growth. Environmental influences like breathing patterns can heavily influence this development. Habitual mouth breathing during these formative years not only increases the risk of dental and orthodontic issues, but also contributes to sleep problems, behavioural changes, and poor posture.

The longer the issue goes untreated, the more difficult it becomes to reverse the physical and functional consequences. When air is inhaled through the nose, it is cleaned of dust and pathogens, warmed, and moisturised before reaching the lungs. Mouth breathing, however, bypasses these critical steps, potentially causing a variety of health complications including respiratory infections, poor oxygenation, and developmental issues.

Early signs of mouth breathing in children

Early detection is essential. Signs parents should watch for include:

  • Lips apart at rest, even when quietly engaged
  • Frequent snoring or noisy breathing during sleep
  • Dry mouth, cracked lips, or excessive thirst in the morning
  • Persistent bad breath (Al-Awadi & Al-Casey, 2013)
  • Daytime tiredness, irritability, difficulty focusing
  • Forward head posture (Krakauer & Guilherme, 2000)
  • Dark circles under the eyes (“allergic shiners”)
  • Narrow, elongated facial appearance (“long face syndrome”)
  • Speech delays or lisping

Recognising these symptoms early allows for interventions that can drastically improve a child’s development trajectory.

Why early intervention matters

Mouth breathing is often dismissed as a harmless habit — but in reality, it is a red flag that something in a child’s airway function or oral posture is out of balance. If it’s allowed to continue unchecked during key growth years, the consequences can be both structural and systemic. Myofunctional therapists, orthodontists, and airway-focused clinicians consistently see the long-term impact that early mouth breathing can have across multiple areas of health and development:

  • Facial development changes – High-arched palates, narrow jaws, elongated faces – When a child chronically breathes through the mouth, their tongue no longer rests in its natural position — the roof of the mouth. This lack of upward pressure impedes proper palate growth, often resulting in high-arched palates, narrow upper jaws, and elongated mid-faces. These craniofacial changes don’t just affect appearance; they reduce airway volume and increase the risk of obstructive sleep conditions (Lin et al., 2022)
  • Dental complications – Crowding, malocclusion, bite problems – A narrow palate typically means there is less room for adult teeth to erupt properly, leading to dental crowding, malocclusion (misalignment of the bite), and the need for future orthodontic intervention. Additionally, a low tongue posture can contribute to open bites and other complex dental presentations that require early orthotropic or orthodontic management (Al-Awadi & Al-Casey, 2013).
  • Postural issues – Forward head posture and spinal misalignments – Mouth breathers often compensate for poor airflow by jutting their head forward or tilting it back to open the airway. Over time, this “forward head posture” can lead to muscular imbalances, spinal misalignments, and chronic tension in the neck, shoulders, and upper back. Studies show that postural adaptations in childhood can persist into adulthood and contribute to long-term musculoskeletal discomfort (Krakauer & Guilherme, 2000).
  • Sleep-disordered breathing (SDB) – Leading to disturbed sleep patterns, poor oxygenation, and hormone disruption. Perhaps most concerning are the effects of mouth breathing on sleep. Children who breathe through their mouths at night are more likely to snore, wake frequently, or develop conditions such as obstructive sleep apnoea. This results in fragmented sleep, poor oxygen saturation, and a cascade of hormonal disruptions that affect growth, immune regulation, and cognitive performance (Valcheva et al., 2018).

Left unaddressed, mouth breathing doesn’t just affect appearance — it undermines a child’s ability to thrive. Research and clinical experience show strong associations between chronic mouth breathing and poor concentration, hyperactivity, low energy levels, irritability, and emotional dysregulation. Many children are misdiagnosed with behavioural disorders such as ADHD, when in fact, the root issue may be poor sleep and oxygen deprivation due to compromised airway function.

That’s why early identification and intervention are critical. Parents, educators, and health professionals should be aware of the signs and take action at the first indication. With proper guidance — including myofunctional therapy, nasal hygiene strategies, and interdisciplinary care — these patterns can be corrected, often before they require surgical or orthodontic intervention.

How sleep-disordered breathing can mimic ADHD

One of the most frequently overlooked consequences of chronic mouth breathing in children is the development of sleep-disordered breathing (SDB) — a condition characterised by repeated interruptions in breathing during sleep, such as snoring, upper airway resistance, or obstructive sleep apnoea. These interruptions disrupt the natural architecture of sleep, particularly the deeper, restorative stages that are vital for brain function, emotional regulation, and behaviour.

Critically, the daytime symptoms caused by SDB often mirror those seen in attention-deficit/hyperactivity disorder (ADHD) — including poor concentration, impulsivity, irritability, and restlessness. This overlap can lead to misdiagnosis, with children being labelled as inattentive or hyperactive when the true cause is poor sleep quality stemming from compromised airway function.

A 2021 study published in the International Journal of Clinical Pediatric Dentistry underscores that children with obstructed nasal breathing due to enlarged tonsils or adenoids often present with behavioural problems typically associated with ADHD. The study reported cognitive and emotional improvements following airway-focused treatment (Kalaskar et al., 2021).

Further support comes from a study by Constantin et al., published in Behavioural Sleep Medicine, which found that children with SDB experienced significant impairments in executive function — the brain’s system for organising, planning, and managing attention and behaviour. The authors described overlapping profiles between children with SDB and those diagnosed with ADHD, particularly in sustaining focus, controlling impulses, and regulating emotions (Constantin et al., 2015).

The academic consequences are also substantial. Galland et al., writing in Pediatrics, found that poor sleep due to SDB had a measurable negative effect on academic achievement. Children with disrupted sleep performed worse on tasks involving memory, reading comprehension, and verbal reasoning — even when adjusting for external factors (Galland et al., 2015).

These findings were echoed in a 2019 meta-analysis by Luo et al., published in Early Education and Development, which analysed data across 17 studies. The research showed that children with untreated SDB had significantly lower scores in reading, maths, working memory, and verbal IQ. The most affected areas were those requiring sustained mental effort and linguistic reasoning — which also align closely with the cognitive challenges faced by children with ADHD (Luo et al., 2019).

Many children diagnosed with ADHD are actually showing symptoms of chronic sleep deprivation caused by an undiagnosed breathing disorder.

In light of this compelling body of evidence, more clinicians are calling for routine airway and sleep assessments prior to diagnosing ADHD. Addressing the root causes of SDB — such as nasal obstructions, low tongue posture, or habitual mouth breathing — can dramatically improve attention, behaviour, and emotional resilience.

Treatment pathways may include ENT evaluation, myofunctional therapy, and support for nasal breathing habits, which together restore healthy breathing and quality sleep, unlocking a child’s full cognitive and behavioural potential.

Correcting airway function may not just improve sleep — it can unlock your child’s ability to focus, learn, and thrive.

For more on how mouth breathing affects sleep and brain development, visit our in-depth guide:
Mouth breathing and sleep in children

How myofunctional therapy can help

Myofunctional therapy is a research-backed, non-invasive intervention that focuses on retraining the muscles of the tongue, lips, cheeks, and throat to restore optimal oral and airway function. At its core, the therapy helps children develop correct habits for breathing, chewing, swallowing, and resting posture — all of which are foundational to healthy craniofacial development and overall wellbeing.

Learn more about how myofunctional therapy works to correct mouth breathing — and why it’s a game-changer for developing faces.

Children who mouth breathe often have poor tone and coordination in these critical muscle groups, which can lead to airway collapse during sleep, inefficient swallowing, and compensatory postures that affect alignment and growth. Myofunctional therapy addresses these dysfunctions at the muscular level, using targeted exercises to build strength, coordination, and proper function.

Recent studies highlight several important outcomes:

  • Improved sleep quality: Myofunctional therapy significantly reduces the severity of sleep-disordered breathing by decreasing airway collapse during sleep. Strengthened tongue and oropharyngeal muscles help keep the airway open, leading to deeper, more restorative rest (Harding et al., 2021). This complements the findings discussed in our guide to sleep disorders and breathing
  • Reduced ADHD-like symptoms: There is growing recognition that poor sleep — especially caused by disrupted breathing — can mimic the behavioural symptoms of ADHD. By improving nasal breathing and sleep quality, myofunctional therapy has been shown to alleviate inattention, impulsivity, and hyperactivity in some children misdiagnosed with neurodevelopmental conditions (Ivanov et al., 2024). Learn more about the connection in our article on mouth breathing and sleep in children.
  • Better academic and physical outcomes: Oxygenation during sleep is vital for brain development. Children who breathe well at night are more alert, focused, and emotionally regulated during the day. Over time, this leads to improved behaviour, learning outcomes, and greater engagement in school and physical activities.
  • Whole-child transformation: The benefits of a personalised myofunctional therapy plan go beyond biomechanics. As children begin to sleep better, breathe more easily, and feel more regulated, parents often report improved mood, confidence, speech clarity, and social interaction. These changes can be life-changing for both the child and their family. For a closer look at how tongue posture supports speech development, see our deep dive into tongue function and speech clarity.

A personalised therapy plan doesn’t just restore function — it transforms a child’s sleep, learning, mood, and confidence. Discover the full list of benefits here.

Practical steps parents can take

If you suspect your child is mouth breathing, early action is key. You don’t need a medical degree to start noticing patterns or raising concerns. Here’s what you can do today:

  • Observe closely: Watch your child during quiet activities or sleep. Do they breathe with their mouth open when watching TV? Are their lips parted during sleep? Do they snore, grind their teeth, or frequently toss and turn at night?
  • Document symptoms: Keep a short log of signs such as dry lips or mouth upon waking, noisy breathing, frequent waking, bedwetting, irritability, lack of focus, or daytime sleepiness. These symptoms may point toward sleep-disordered breathing or an airway obstruction.
  • Book a professional evaluation: Reach out to a myofunctional therapist, airway-aware dentist, ENT, or paediatric sleep specialist. A proper assessment will look at tongue posture, nasal patency, jaw development, and functional breathing patterns. Contact Breathe First to schedule an assessment.
  • Encourage nasal breathing: Prompt your child to close their lips gently and rest their tongue against the roof of the mouth during the day. Play “closed lips” games, model proper breathing yourself, or gently remind them throughout the day in a positive way. These simple changes — along with techniques like nasal rinsing and humming — can promote healthier breathing habits.
  • Explore nasal support tools: Myotape can be a gentle training aid to help children learn to keep their lips sealed during sleep and rest, reinforcing safe nasal breathing.
  • Identify and treat root causes: Chronic allergies, enlarged adenoids or tonsils, or persistent nasal congestion can all drive mouth breathing. Work with your healthcare provider to address these contributors — this might include allergy management, nasal rinses, or ENT evaluation.

Remember, the earlier these habits are addressed, the greater the opportunity to guide healthy growth — often without the need for more invasive treatments later on. Myofunctional therapy offers a proactive, empowering path forward, helping children breathe, sleep, and thrive with confidence.

Starting early, even with simple exercises and support tools, gives your child the best chance for natural growth and a healthy airway. Get started with at-home myofunctional therapy exercises.

Broader applications and specialist support

Mouth breathing is just one of many conditions that myofunctional therapy can address. The therapy is increasingly used across various populations:

  • Singers rely on oral posture, tongue control, and diaphragmatic breathing — all of which benefit from myofunctional techniques.
  • Athletes use breathwork to improve performance and recovery, with therapy enhancing oxygen uptake and neuromuscular control.
  • Those with jaw pain or TMJ disorders often find relief when muscle imbalances are addressed in combination with manual therapy.

Manual techniques can dramatically accelerate outcomes when combined with myofunctional therapy.”
Explore manual therapy for voice, swallowing, and TMJ disorders

Mouth breathing is far more than a minor habit — it is a warning sign of potential health, developmental, and academic challenges. Early recognition and intervention are vital to giving your child the best start in life.

Contact Breathe First today to book a comprehensive airway and myofunctional therapy assessment. Together, we can help your child breathe better, sleep better, learn better — and live better.

FAQs

Still unsure if your child’s mouth breathing is something to worry about? You’re not alone.
Many parents notice signs like snoring, open-mouth posture, or daytime tiredness — but aren’t sure what they mean or where to turn. This section answers the most common questions we receive from families who are just beginning to explore the connection between breathing, development, and behaviour.

From causes and symptoms to treatment timelines and outcomes, we aim to provide clear, supportive information that helps you feel confident taking the next step.

What causes children to mouth breathe?

Mouth breathing in children usually begins as a response to some kind of obstruction or difficulty in the nasal passages. This might be due to chronic nasal congestion caused by allergies or frequent colds, or it could stem from anatomical issues such as enlarged tonsils or adenoids that physically block airflow through the nose. In some cases, children may have a deviated septum or structural narrowing of the nasal airway that makes breathing through the nose difficult or uncomfortable. Over time, if the child doesn’t receive treatment or guidance, the mouth breathing becomes habitual — especially during sleep — and may continue even after the original cause has been resolved. Poor tongue posture, low muscle tone in the face and lips, and lack of nasal breathing awareness all reinforce this cycle.

Can mouth breathing affect my child’s school performance?

Yes, mouth breathing can have a significant impact on your child’s academic performance — and it often goes unnoticed. When a child breathes through their mouth, particularly during sleep, it can lead to poor oxygen intake and restless nights. Without high-quality, restorative sleep, the brain doesn’t have a chance to properly consolidate memory or support the energy needed for learning and emotional regulation. As a result, children may struggle with concentration, become more irritable, and even show signs that mimic behavioural conditions like ADHD. Teachers might notice inattention, impulsivity, or difficulty following instructions. These issues aren’t rooted in intelligence or effort — they’re often a symptom of disrupted sleep and poor breathing patterns. By correcting mouth breathing and supporting healthier sleep, many children show dramatic improvements in focus, mood, and classroom engagement.

How is myofunctional therapy different from orthodontic treatment?

While orthodontic treatment focuses on the alignment of teeth and jaws — typically using braces, retainers, or expanders — myofunctional therapy takes a different approach by addressing the underlying muscular habits that influence oral development in the first place. Myofunctional therapy retrains the muscles of the tongue, lips, cheeks, and throat to function in harmony, promoting better posture, nasal breathing, and correct swallowing patterns. In many cases, myofunctional therapy is the missing piece in ensuring that orthodontic work is successful and long-lasting. For example, if a child has a low resting tongue posture and continues to mouth breathe after orthodontic treatment, the teeth are more likely to shift back out of place. Combining both approaches gives children the best chance at a stable, healthy airway and aligned bite.

When is the best time to start myofunctional therapy?

The most effective time to begin myofunctional therapy is during early childhood, when the face, jaw, and airway are still developing. Starting young allows us to guide growth patterns before dysfunction becomes permanent, helping to prevent the need for more invasive treatments later on. That said, it’s never too late. Many teenagers and even adults see incredible results from therapy, particularly those dealing with sleep issues, orthodontic relapse, jaw tension, or postural problems. The important thing is not when you start, but that you start — because therapy works by gradually changing habits and muscle function, improvements are possible at any age. Whether your child is four or fourteen, there’s real value in addressing these patterns as soon as they’re identified.

What happens if mouth breathing is left untreated?

When mouth breathing continues unchecked throughout childhood, it can cause a ripple effect of health and developmental problems. Over time, the constant open-mouth posture can influence how the face and jaws grow, often resulting in a narrow upper arch, a high palate, or a long, flat-looking face. This not only affects appearance but also restricts the airway, making sleep more difficult and less restful. Children may begin to experience more frequent illnesses, poor dental health, and signs of fatigue, anxiety, or emotional outbursts. In the classroom, the consequences often show up as reduced attention span, memory issues, or disruptive behaviour — problems that may be mislabelled as learning difficulties. Some children develop speech issues or tongue thrusts that affect articulation. By the time they reach adolescence, these patterns can be difficult — though not impossible — to reverse. The earlier these habits are identified and treated, the better the long-term outcome for health, growth, and emotional wellbeing.

References

Picture of Emily Kirkcaldy

Emily Kirkcaldy

Emily is the Owner and Lead Clinician at Breathe First with over 20 years of experience as a Speech and Language Therapist, dedicating the last 5 years to Orofacial Myofunctional Disorders and breath Re-Education. Emily is a certified myofunctional therapist, specializing in improving oral function and breathing techniques.With a passion for helping people achieve optimal health through myofunctional therapy, she focuses on exercises that enhance tongue posture, speech clarity, and breathing patterns. Emily combines her expertise with a patient-centered approach, offering tailored therapies for individuals with sleep apnea, speech issues, and oral-facial muscle dysfunction. She is dedicated to educating the public on the importance of proper oral health and functional breathing.
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