Mouth Breathing in Adults: Causes, Signs, Sleep and When to Seek Help

Waking with a dry mouth? Snoring? Grinding your teeth? Feeling tired despite spending enough time in bed?

Mouth breathing is often thought of as a childhood problem, but I see adults in practice who have been breathing this way for years without ever questioning why.

Sometimes it's obvious. Sometimes it isn't.

As a dentist with a special interest in airway health, I don't think the most important question is simply:

“Do you mouth breathe?”

I want to know:

“Why are you mouth breathing in the first place?”

Because mouth breathing isn't a diagnosis. It's a sign that deserves context.

What causes mouth breathing in adults?

There isn't one single cause.

For some people, breathing through the mouth develops because comfortable nasal breathing is difficult. This may be related to:

• nasal congestion or allergies

• a deviated nasal septum

• enlarged turbinates

• nasal valve problems

• other structural causes of nasal obstruction

  
  

For others, mouth breathing may have become a long-standing pattern, even when the original reason has changed.

Sometimes it also sits alongside concerns involving sleep, snoring, tongue function, jaw position, clenching or oral function.

Importantly, mouth breathing does not mean that somebody has obstructive sleep apnoea (OSA).

But it can be one piece of a much bigger picture.

Signs of mouth breathing in adults

You might recognise:

• waking with a dry mouth or throat

• sleeping with your mouth open

• snoring or noisy breathing

• drooling onto the pillow

• difficulty breathing comfortably through your nose

• waking feeling unrefreshed

• daytime tiredness

• clenching or grinding your teeth

• morning headaches

• jaw, facial or neck tension

  
  

None of these symptoms alone provides a diagnosis.

But when several occur together, I become interested in the bigger picture.

Mouth breathing and sleep

Sleep is one area I pay particular attention to, because how someone breathes during sleep can add another piece to the clinical picture.

Mouth breathing does not equal obstructive sleep apnoea (OSA). But when it occurs alongside persistent snoring, pauses in breathing, gasping or significant daytime sleepiness, I take notice.¹

Rather than simply trying to “train” the mouth to stay closed, I want to understand what is driving the mouth breathing and whether further investigation is appropriate.

Why I don't simply tell everyone to tape their mouth

Mouth taping has become incredibly popular on social media.

A 2025 systematic review found limited evidence supporting its general use and highlighted potential risks, particularly when nasal obstruction is present.²

Before considering mouth taping, I want to know whether someone can breathe comfortably through their nose and whether any sleep or airway concerns need investigating first. That may mean ENT or medical assessment or, where oral function may be contributing, an airway and myofunctional assessment can help identify what needs addressing.

How I assess an adult who mouth breathes

My starting point isn't an exercise or an appliance. It's an assessment.

1. Breathing

   Nasal breathing, breathing patterns and possible obstruction.

2. Sleep

   Snoring, sleep quality and symptoms that may warrant further investigation.

3. Tongue function

   Resting posture, movement, restriction and compensation.

4. Jaw and TMJ

   Jaw movement, clicking, discomfort, clenching and muscular tension.

5. Oral function

   How the lips, tongue and jaw work together.

6. Bite and dental health

   Bite stability, tooth wear, dry mouth and other dental clues.

I look beyond the obvious. After 15+ years in dentistry, I’ve learned not to stop at what I see. I want to understand why it’s there.

So, can mouth breathing be treated?

Yes. But the right approach depends on why it's happening.

For one person, the priority may be investigating nasal obstruction with an ENT. For another, it may be exploring possible sleep-disordered breathing.

For someone else, once the airway has been appropriately considered, the focus may turn to nasal breathing, tongue posture, lip seal and oral function.

Sometimes, several professionals need to work together.

That's why I don't believe in a one-size-fits-all approach to mouth breathing.

Perhaps the better question isn't:

“How do I stop mouth breathing?”

It's “Why am I doing it?”

When should you seek help?

If you regularly breathe through your mouth, particularly at night, and also experience snoring, poor-quality sleep, dry mouth, grinding, jaw symptoms, or difficulty breathing comfortably through your nose, it may be worth looking beyond the symptoms themselves.

Ready to understand the bigger picture?

My Airway & Myofunctional Assessment is a comprehensive 90-minute appointment for adults and children in Camberley, Surrey, welcoming patients from Berkshire, Hampshire and further afield.

You'll receive a detailed written report and a personalised roadmap of recommendations and next steps, including onward referral where appropriate.

See the whole picture. Understand what matters. Know what to do next.

Dr JJ

Airway-Focused Dentist

Breathing • Sleep • Function

Evidence & Further Reading

1. Shah J, et al. (2024). Effect of sleep on oral health: A scoping review. Sleep Medicine Reviews.

2. Rhee J, et al. (2025). Breaking social media fads and uncovering the safety and efficacy of mouth taping in patients with mouth breathing, sleep-disordered breathing, or obstructive sleep apnea: a systematic review. PLOS One.

3. Maniaci A, et al. (2024). Oral Health Implications of Obstructive Sleep Apnea: A Literature Review. Biomedicines.

   
   

→ Read: Mouth Breathing in Children – Causes, Signs and When to Seek Help