Mouth Breathing: What it is, Causes and Impact

Nasal breathing is the usual physiological pattern: air enters through the nose, where it is filtered, warmed, and humidified, and then travels through the airways to the lungs. When this pattern is altered and the individual breathes predominantly through the mouth, it is called oral breathing.

This phenomenon may seem harmless, but scientific evidence suggests that mouth breathing, especially when persistent, is associated with multiple consequences for health, development, and quality of life.

In this article we will explore in detail what mouth breathing is, what the most frequent causes are, and what impact it can have, including implications for speech therapy intervention. The goal is to provide a complete and accessible overview so that professionals and parents understand the importance of this breathing pattern.

Mouth breathing: what is it?

Ideally, humans should breathe primarily through their nose. Air enters through the nostrils, is filtered, warmed, and humidified before reaching the lungs. In oral breathing, on the other hand, most of the air enters through the mouth, often with the lips slightly parted and the tongue lowered to the floor of the mouth.

Mouth breathing is generally considered to occur when a child (or adult) breathes predominantly through their mouth for at least several consecutive months, even at rest and during sleep. We're not just talking about the occasional situation where a child has a cold for a few days. We're talking about an established breathing pattern.

If you consult our Speech therapy glossary, You will find oral breathing described as a habit associated with orofacial alterations and myofunctional patterns. In simple terms: when mouth breathing becomes habitual, the body adapts… and this adaptation has consequences.

How should nasal breathing be?

Before understanding mouth breathing, it helps to remember the function of nasal breathing. When breathing through the nose:

• The air is filtered, which reduces the entry of dust, allergens, and irritating particles.

• The air is heated and humidified, protecting the lower respiratory tract.

• The passage of air through the nose promotes a proper balance of the facial muscles, tongue, and lips.

When mouth breathing predominates:

• The air enters cold and dry, irritating the throat and respiratory tract.

• The mouth tends to stay open, the tongue is lowered, and the lips are not very active.

• The head position changes to facilitate air intake.

These changes, maintained over time, help explain why mouth breathing is associated with dental problems, facial growth abnormalities, sleep difficulties, fatigue, learning difficulties, and speech disorders.

Main causes of mouth breathing in children and adults

Mouth breathing rarely appears "out of nowhere." Generally, there is an initial cause, to which habit later develops. The most frequent reasons include:

1. Nasal and upper airway obstruction

Many children who breathe through their mouths have some form of upper airway obstruction, such as:

• • Persistent allergic rhinitis.

  • Enlarged tonsils and adenoids.

  • Deviated nasal septum.

  • Nasal polyposis or recurrent sinus infections.

In this context, the child begins to breathe through their mouth to "get around" the difficulty in getting air through the nose. If the problem is not identified and treated, mouth breathing remains the pattern even after the most acute phase.

2. Habits and behavioral factors

Mouth breathing is not always the result of a very obvious obstruction. Some habits can promote this pattern, for example:

• • Prolonged use of pacifiers or baby bottles.

  • Digital suction (thumb sucking).

  • Open-mouthed posture during activities requiring concentration (television, tablet, school).

  • Mouth slightly open during sleep, even without visible nasal congestion.

Over time, these habits alter lip tone, tongue resting position, and how facial structures grow. All of this reinforces the tendency toward mouth breathing.

3. Other associated medical conditions

In some cases, mouth breathing is associated with:

• • Asthma and other respiratory diseases.

  • Poorly controlled seasonal allergies.

  • Sleep disorders, such as snoring or sleep apnea.

In these cases, a medical evaluation (pediatrician, otolaryngologist, allergist) is essential to treat the underlying cause, in parallel with the intervention of Speech therapy.

Signs and symptoms of mouth breathing in daily life.

Identifying mouth breathing early is half the battle in reducing its impact. Some signs that parents and educators can observe are:

• Lips almost always slightly parted, even at rest.

• Dry mouth, chapped lips, and frequent thirst.

• Snoring or sleeping with your mouth open.

• Restless sleep, with constant movements and an untidy pillow.

• Dark circles under the eyes, daytime fatigue, irritability.

• Slow chewing, open mouth while eating, difficulty closing lips to swallow.

• A nasal or "trapped" voice, as if always congested.

In a school setting, mouth breathing can be linked to difficulty maintaining attention, complaints of fatigue, lower-than-expected academic performance, and a greater tendency towards distractions.

When these signs come together language delays, For situations involving sound substitutions or difficulties with reading and writing, it's worthwhile to explore resources such as the article on... Language delay or the page about Dyslexia, and seek an evaluation in speech therapy.

Mouth breathing and its impact on facial and dental development.

Mouth breathing doesn't just alter "the air that enters." Over time, it modifies how the face grows and how the teeth align. The low tongue position and open mouth favor:

• Higher and narrower palate (roof of the mouth).

• A narrower upper jaw leads to a lack of space for the teeth.

• A more retracted jaw or changes in bite.

• A more elongated face, with a tired expression.

These characteristics are described in several studies as typical of "mouth breathing." The good news is that, when identified early, many of these changes can be mitigated through a combination of orthodontics, respiratory retraining, and myofunctional therapy.

Mouth breathing, sleep, and learning

Poor sleep isn't just about "not sleeping enough." It's also about poor quality sleep. Mouth breathing is associated with fragmented sleep, micro-awakenings, snoring, and in some cases, sleep apnea. The child may even sleep for many hours, but wakes up as if they've never rested.

This poor sleep quality is related to:

• Daytime sleepiness.

• Difficulty concentrating.

• Irritability and mood swings.

• Greater propensity for errors and forgetfulness.

Several studies have shown that children with mouth breathing and sleep-disordered breathing have more difficulties with attention, memory, and learning than children who breathe primarily through their nose. In practice, this translates into more effort to keep up with the class, more frustration, and often an unfair label of "inattentive" or "lazy.".

When mouth breathing, poor sleep quality, and language or reading difficulties combine, the risk of academic difficulties increases. That's why it's so important to look at the child holistically and, if necessary, cross-reference the medical assessment with an assessment in [a specific educational setting/institution]. Online speech therapy.

Mouth breathing and speech: what is the relationship?

Mouth breathing is also a central theme in orofacial motor skills, one of the pillars of speech therapy. The same muscles we use to breathe properly are involved in chewing, swallowing, and speaking.

When a child breathes primarily through their mouth:

• The lips tend to become less toned and have difficulty sealing completely.

• The tongue remains low, away from the palate, which interferes with the production of some sounds.

• The coordination between breathing, chewing, swallowing, and speaking becomes less efficient.

In speech, this can translate into distortions of sounds such as /s/, /z/, /ʃ/ (x), /ʒ/ (j), and sometimes /l/. The speech may sound...

Childish, imprecise, or "muffled." In some cases, mouth breathing also coexists with other speech disorders, such as... childhood apraxia of speech or a dysarthria, which require a detailed assessment by the speech therapist.

Fluency can also be affected. Children who sleep poorly, breathe through their mouths, and feel constantly tired may experience increased speech tension or worsening of conditions such as... childhood stuttering.

How is mouth breathing assessed?

The assessment of oral breathing is ideally multidisciplinary. It typically involves:

• Clinical observation of the face, posture, lips, and tongue.

• Assessment of respiratory patterns at rest, during speech, and during specific tasks.

• Analysis of associated functions: chewing, swallowing, blowing, articulation of sounds.

• Gathering information about sleep, behavior, and school performance.

In many cases, the speech therapist It involves coordination with the pediatrician, the otolaryngologist, the orthodontist, or other professionals.

It is crucial to determine if there is a physical obstruction that requires medical or surgical treatment (for example, adenoids (very high) before asking the child to close their mouth and "just breathe through their nose.".

Combining objective assessment data with the history provided by the parents allows for the development of a personalized intervention plan, tailored to the child's age, family context, and specific needs.

Treatment and retraining of mouth breathing.

Treatment for mouth breathing almost always involves two approaches: addressing the underlying cause and retraining the breathing pattern.

1. Treat the underlying cause.

If there is significant nasal obstruction, the doctor may:

• • Adjust medication for rhinitis or allergies.

  • Monitor recurrent sinus infections.

  • Assess the need for surgical treatment (e.g., very enlarged adenoids or tonsils).

Without this correction, it is difficult to establish a comfortable nasal breathing pattern.

2. Retrain breathing patterns with speech therapy.

Then (or in parallel), the intervention comes into play. Speech therapy. The speech therapist works with the child (and the family) to:

• • Practice breath awareness.

  • Promote a resting posture with lips closed and tongue on the palate.

  • Strengthen the orofacial muscles through specific exercises.

  • Integrate nasal breathing into daily activities (playing, talking, eating, studying).

Many of these steps are explained, with practical examples, in content such as the article on Speech therapy: exercises that work. The intervention is most effective when the family actively participates and helps transform the exercises into habits.

What can you do at home to help a child with mouth breathing?

No checklist can replace an individual assessment, but there are simple actions that make a difference when mouth breathing is present:

• Note: Pay attention to whether the child sleeps with their mouth open, snores, or wakes up tired or irritable.

• Reduce prolonged oral habits.Pacifiers, bottles, and thumb sucking continued beyond the recommended age hinder proper nasal breathing.

• Encourage good posture: Straight torso, screen at eye level, to avoid head and neck imbalances.

• Reinforce nasal hygiene., according to the pediatrician's instructions.

• Maintain a smoke-free environment with allergen control. whenever possible.

Above all, don't trivialize comments like "he breathes through his mouth, but only when he's distracted" or "she snores, but she's always been like that." If something seems persistent, it's worth investigating.

When to seek professional help

You should seek help if you notice, repeatedly:

• Mouth breathing, while awake or asleep.

• Frequent snoring, pauses in breathing, or very restless sleep.

• Dry mouth, chapped lips, dark circles under the eyes.

• Constant fatigue, complaints of headaches, difficulty concentrating.

• Changes in speech, sound substitutions, infantile speech.

In these cases, the first step may be to speak with the pediatrician. Following that, an evaluation at... Speech therapy and, if necessary, a consultation with an otolaryngologist or orthodontist.

If commuting is difficult or if you prefer more flexibility, the option of Online speech therapy It can be a safe and effective alternative, especially for exercise monitoring and parental guidance.

Conclusion

Mouth breathing is not just a "habit" of breathing through the mouth. It is a breathing pattern that, if maintained over time, influences facial growth, tooth alignment, sleep quality, learning, and how a child speaks and interacts with others.

By understanding what mouth breathing is, its causes, and its impact, you gain the tools to act sooner. Observing, questioning, and seeking a specialized evaluation is an act of care that can prevent years of fatigue, academic difficulties, and frustration.

The earlier the intervention, the greater the likelihood of reversing or minimizing the changes associated with mouth breathing.

The combination of medical monitoring, orthodontics when indicated, and a consistent speech therapy plan is, today, the most effective way to restore to the child what should be natural: breathing well, speaking clearly, and growing up healthier and more confident.