What is mouth breathing and how does it affect children's development?

Does your child sleep with an open mouth, snore or struggle with concentration at school?

TLDR: Mouth breathing is breathing through the mouth instead of the nose, either during sleep or throughout the day. In children, chronic mouth breathing can affect facial development, dental alignment, sleep quality, concentration, and overall health, potentially leading to a narrow jaw, dental problems, fatigue, and behavioural challenges.

Understanding mouth breathing in children is crucial because early intervention can prevent long-term developmental and health consequences.

How does mouth breathing develop in children?

Mouth breathing in children typically develops when nasal breathing becomes difficult or blocked. The body compensates by breathing through the mouth to ensure adequate oxygen intake.

Common causes include enlarged tonsils and adenoids, which physically obstruct the nasal airways. According to research published in PMC, adenoid hypertrophy is one of the primary contributors to mouth breathing in children aged 6 to 12 years.

Other contributing factors include:

• Chronic allergies: Seasonal or year-round allergies cause nasal congestion and inflammation

• Nasal polyps: Benign growths in the nasal passages that restrict airflow

• Deviated septum: Structural abnormality that blocks one or both nasal passages

• Habitual behaviour: Sometimes mouth breathing continues even after the original obstruction is resolved

In some cases, mouth breathing becomes a learned habit. Even after treating the underlying cause, children may continue breathing through their mouth simply because it has become their normal pattern.

How does mouth breathing affect facial and dental development?

One of the most significant impacts of chronic mouth breathing in children is on craniofacial development. The way a child breathes directly influences how their face and jaw grow.

Research from PMC demonstrates that mouth breathing children show measurable differences in facial proportions compared to nasal breathing children, particularly in facial height and jaw alignment.

Typical developmental changes include:

• Elongated face shape: The face grows longer and narrower rather than developing balanced proportions

• Narrow upper jaw: The palate becomes V-shaped instead of the ideal U-shape, reducing space for teeth

• Dental crowding: Insufficient jaw width leads to crooked or overlapping teeth

• Open bite: Front teeth don't meet properly when the mouth closes

• Recessed chin: The lower jaw may sit further back than ideal

According to a cephalometric study, children aged 6 to 14 who are mouth breathers show significantly higher facial height measurements and steeper mandibular plane angles compared to nasal breathers.

What are the effects on sleep quality and behaviour?

Mouth breathing during sleep significantly disrupts a child's rest quality and daytime functioning. Children who breathe through their mouth at night often experience fragmented sleep patterns and reduced oxygen saturation.

Common sleep-related symptoms include:

• Snoring: Often the first noticeable sign that parents observe

• Restless sleep: Frequent position changes and movement throughout the night

• Night waking: Difficulty staying asleep for extended periods

• Morning fatigue: Waking up tired despite adequate time in bed

Poor sleep quality directly impacts daytime behaviour and cognitive function. Children with chronic mouth breathing often struggle with concentration difficulties, reduced school performance, and behavioural challenges that may resemble ADHD symptoms.

Want to understand more about how breathing affects sleep? Read our guide on how mouth breathing impacts sleep quality and snoring.

The connection between sleep and focus is well-documented. Learn more about how better sleep improves concentration at school.

How does mouth breathing affect overall health and immunity?

The nose serves as the body's natural air filter and conditioner. When children bypass this system through mouth breathing, they lose important protective mechanisms.

Nasal breathing filters out particles, bacteria, and viruses while warming and humidifying the air. Mouth breathing delivers unfiltered, dry air directly to the lungs and throat.

Health consequences include:

• Increased infections: More frequent colds, throat infections, and respiratory illnesses

• Dry mouth: Reduced saliva production leads to increased dental cavities and gum problems

• Bad breath: Chronic halitosis from dry mouth and bacterial growth

• Weakened immunity: Loss of nasal defence mechanisms reduces immune response

Research from CBCT-based studies shows that mouth breathing children aged 10 to 12 have significantly different upper airway morphology, which can affect long-term respiratory health.

How does mouth breathing affect speech development?

Chronic mouth breathing can interfere with proper speech development in children. The tongue position during mouth breathing is typically low and forward, rather than resting against the roof of the mouth.

This altered tongue position affects:

• Articulation: Difficulty pronouncing certain sounds clearly, particularly S, T, D, and L sounds

• Tongue thrust: Forward tongue movement during swallowing that can worsen dental problems

• Voice quality: Nasal or muffled speech patterns

Speech therapy and myofunctional therapy can help retrain proper tongue position and breathing patterns. These therapies work best when combined with addressing the underlying cause of mouth breathing.

How can you recognize mouth breathing in your child?

Early recognition allows for timely intervention. Parents and caregivers should watch for these common signs during both day and night.

Daytime indicators:

• Habitually open mouth, especially during concentration or screen time

• Dry, cracked lips

• Chronic nasal congestion or difficulty breathing through the nose

• Noisy breathing or audible breathing during quiet activities

• Frequent yawning or appearing tired despite adequate sleep hours

Night-time indicators:

• Snoring or heavy breathing during sleep

• Open mouth position while sleeping

• Restless sleep with frequent position changes

• Waking with dry mouth or throat

• Morning headaches or grogginess

If you notice multiple signs, particularly during sleep, it's important to consult with healthcare professionals for proper assessment.

When should you seek professional help?

While occasional mouth breathing during a cold is normal, persistent mouth breathing requires medical attention. Early intervention prevents long-term developmental consequences.

Consult a GP or paediatrician if your child:

• Breathes through the mouth most of the time, day or night

• Snores regularly or has difficulty breathing during sleep

• Shows signs of sleep disturbance or daytime fatigue

• Has chronic nasal congestion lasting more than two weeks

• Experiences frequent respiratory infections or allergies

Your GP may refer you to specialists including:

• ENT specialist: To assess tonsils, adenoids, and nasal structure

• Orthodontist: To evaluate jaw development and dental alignment

• Speech therapist: For myofunctional therapy to retrain breathing and tongue position

• Allergist: If allergies are contributing to nasal congestion

Important: Do not use mouth tape on children without professional guidance. While Zippit mouth tape is effective for adults, children require proper medical assessment and treatment of underlying causes first.

For more information on when professional help is needed, read our guide on when to consult a GP, specialist or therapist about mouth breathing.

What treatment options are available?

Treatment depends on the underlying cause of mouth breathing. A comprehensive approach often involves multiple specialists working together.

Medical interventions may include:

• Adenoid or tonsil removal: Surgical removal if enlarged tissues block airways

• Allergy treatment: Medications or immunotherapy to reduce nasal inflammation

• Nasal sprays: To reduce congestion and improve nasal breathing

Therapeutic approaches include:

• Myofunctional therapy: Exercises to retrain tongue position and breathing patterns

• Orthodontic treatment: Palatal expanders to widen the upper jaw and create more airway space

• Breathing exercises: Techniques to establish nasal breathing habits

According to cross-sectional research, early intervention has the greatest impact on reversing developmental changes, particularly before adolescence.

Key takeaway: Treatment success requires addressing both the physical obstruction and retraining proper breathing habits, ideally before permanent developmental changes occur.

How can you support nasal breathing at home?

While professional treatment addresses underlying causes, parents can support healthy nasal breathing through daily habits and environmental adjustments.

Practical steps include:

1. Maintain good air quality: Use a humidifier to prevent dry air, especially during winter months

2. Minimize allergens: Regular cleaning, air purifiers, and allergen-proof bedding reduce triggers

3. Encourage nasal hygiene: Gentle nose blowing and saline rinses help clear passages

4. Promote physical activity: Regular exercise supports overall respiratory health

5. Create bedtime routines: Consistent sleep schedules and calm environments improve sleep quality

For temporary nasal congestion, Sniffit nasal strips can help open nasal passages mechanically in older children, but always consult your GP first before using any breathing aids.

Ready to improve your family's breathing health? Start by observing your child's breathing patterns and consult with healthcare professionals if you notice persistent mouth breathing. Early intervention makes the biggest difference in preventing long-term developmental effects.