Is Mouth Breathing in Kids a Big Deal? Signs, Sleep Risks, and What Parents Should Know: Part 1
It’s something parents are mentioning to me more and more.
“His mouth is always open.”
“She snores, but I thought that was normal.”
“He just prefers breathing through his mouth.”
Sometimes it’s said casually. Other times there’s a bigger underlying concern.
So let’s talk about it.
Occasional mouth breathing — during a cold, allergies, or after running around — is completely normal.
But chronic mouth breathing in kids— when a child regularly rests with their mouth open or consistently sleeps with their mouth open — is different. And yes, it can matter more than most people realize.
Why Nasal Breathing Is So Important
The body is designed to breathe primarily through the nose.
Nasal breathing helps:
Filter and humidify air
Produce nitric oxide (which supports oxygen uptake and vascular regulation)
Encourage proper tongue resting posture
Support balanced jaw development
Promote optimal oxygen-carbon dioxide exchange
When children breathe through their nose, the tongue naturally rests on the roof of the mouth. This supports healthy growth of the upper jaw and facial structures.
When breathing shifts to the mouth long-term, those patterns begin to change.
What Research Shows About Mouth Breathing in Children
Research over the past two decades has consistently linked chronic mouth breathing with:
Increased risk of sleep-disordered breathing
Higher rates of pediatric obstructive sleep apnea
Changes in craniofacial growth patterns
Altered tongue posture and swallow mechanics
A recent large-scale pediatric study found that habitual mouth breathing was associated with more than a fourfold increased risk of sleep-disordered breathing in school-aged children.¹
Sleep-disordered breathing in children has been associated with behavioral regulation challenges, attention differences, and learning impacts.²
Separate systematic reviews and meta-analyses have found that chronic mouth breathing is associated with measurable changes in facial skeletal development — including increased lower facial height, altered jaw angles, and narrower maxillary growth.³ ⁴
This does not mean every child who mouth breathes will develop these outcomes. But it does mean persistent mouth breathing is not something to dismiss as “just a habit.”
What Causes Chronic Mouth Breathing?
There are many possible causes:
Enlarged tonsils or adenoids
Chronic allergies
Nasal obstruction
Structural airway differences
Habitual patterns that remain after congestion resolves
Sometimes the original trigger improves, but the breathing pattern remains. The body simply adapts to what it learned. And once that adaptation becomes the default, it can influence sleep, posture, and oral function.
Signs Parents Often Notice
Parents rarely come in saying, “My child has dysfunctional breathing.”
They say:
“He’s always chewing with his mouth open.”
“She struggles to keep her lips closed.”
“His tongue always seems low in his mouth.”
“Speech has been harder than we expected.”
Chronic mouth breathing can fragment sleep — even when it doesn’t meet criteria for full obstructive sleep apnea. Sleep quality influences mood, attention, growth hormone release, and nervous system regulation.
Again — this isn’t about fear. It’s about awareness.
The Posture Connection Most Families Don’t Expect
When a child habitually breathes through their mouth, the head often shifts slightly forward to help maintain airway openness. Over time, this forward head posture can influence:
Tongue resting position
Lip closure
Jaw alignment
Rib cage expansion
Overall muscular balance
Several studies have observed correlations between mouth breathing and altered head and cervical posture in children.⁵
The body adapts to prioritize breathing, and those adaptations can ripple outward into speech clarity, chewing efficiency, and facial growth patterns. I’ll explore this more deeply in Part 2 of this series.
When Is It Worth Exploring?
If your child occasionally mouth breathes during illness, that’s normal.
But if your child:
Habitually rests with lips parted
Snores regularly
Sleeps restlessly
Seems chronically tired
Has persistent articulation or chewing concerns
Their tongue rests behind or on their lower teeth
It’s worth asking questions.
That may mean starting with your pediatrician or ENT to rule out structural concerns. It may also include evaluation by a dentist, orthodontist, or speech-language pathologist trained in orofacial myofunctional therapy (like me!).
A Gentle Perspective
Mouth breathing isn’t a “bad habit.”
It’s often the body’s adaptation to something that needed support.
When we understand the pattern, we can gently guide the body back toward more efficient ones.
In Part 2, we’ll look at how chronic mouth breathing can influence jaw growth, facial development, and posture — and why early awareness makes change easier.
If you’re wondering about your child specifically, please don’t hesitate to reach out.
References
Li, X. et al. (2023). Association between habitual mouth breathing and sleep-disordered breathing in school-aged children. Sleep Medicine, 110, 123–130. PMID: 40919295.
Tan, H.L., Gozal, D., et al. (2023). Pediatric obstructive sleep apnea: implications for neurocognitive and behavioral outcomes. Children (Basel), 10(2), 13.
Abreu, R.R. et al. (2008). Mouth breathing and dentofacial development: A systematic review. Journal of Oral Rehabilitation, 35(9), 718–724.
Zhao, Z. et al. (2021). Effects of mouth breathing on facial skeletal development: A meta-analysis. Orthodontics & Craniofacial Research, 24(3), 305–315.
Okuro, R.T. et al. (2011). Head posture in mouth-breathing children: A systematic review. Brazilian Journal of Otorhinolaryngology, 77(5), 631–638.