Is Mouth Breathing Bad for Children?

Mouth breathing has been linked to behavioral and health problems. But the causes of chronic mouth breathing are often treatable.

Child mouth breathing
Photo: Ermolaev Alexander/Shutterstock

While humans can breathe through their nose, their mouth, or a combination of the two, we function best when we take in oxygen through our noses. That's because the nose purifies, warms, and produces chemicals to keep you healthy when you breathe.

Read on to learn about the benefits of nasal breathing, and the risks, causes, and symptoms of mouth breathing.

How Nasal Breathing Protects You

Nasal breathing keeps you healthy in many ways. For one, the hairs that line your nose and nasal passages are the first line of defense against viruses, bacteria, fungi, dirt, and spores.

Second, your nose warms and humidifies the air you breathe, which is better for your overall respiratory health, especially if you live in a cold climate.

And finally, your nose produces nitric oxide, an important compound that helps boost your cardiovascular and immune systems. Nasal breathing transports the nitric oxide in your nasal passages to your lungs and, eventually, your bloodstream. Researchers have found that nitric oxide may reduce respiratory tract infections by inactivating viruses and hindering their replication.

Is Mouth-Breathing Bad for You?

"Mouth breathing itself is not usually a big problem," says Yami Cazorla-Lancaster, D.O., a pediatrician in Yakima, Washington. "It may cause dryness of the lips and bad breath."

She explains that when people are sick with a head cold, most will breathe through their mouths because their nasal passages are swollen and full of mucus. However, they'll resume taking in air through their nose in a week or two once the cold has passed.

But, if left unresolved in children, mouth breathing has been linked to:

  • Behavioral problems
  • Cavities
  • Constricted airway
  • Facial and dental abnormalities
  • Halitosis (bad breath)
  • Increased tonsil size
  • Learning problems
  • Obstructive sleep apnea (OSA)
  • Periodontal (gum) disease
  • Slower growth
  • Weakened immune system

Chronic mouth breathing that persists for several weeks or months can also signal a larger problem that needs to be addressed.

Causes and Symptoms of Mouth Breathing

"A couple of common causes of chronic mouth breathing include allergies and enlarged tonsils," says Dr. Cazorla-Lancaster. Sleep apnea can also cause mouth breathing.


Dr. Cazorla-Lancaster says that children with allergies that force them to breathe through their mouth may develop the following:

  • Cough
  • Dark circles under their eyes
  • Persistent nasal congestion
  • Throat clearing

Because they won't sleep well, they may be fatigued and have difficulty concentrating in school.

Enlarged tonsils and adenoids

According to Dr. Cazorla-Lancaster, children with enlarged tonsils and adenoids that are partially blocking their airways may experience similar symptoms, including trouble sleeping, snoring, or pauses in their sleep (called sleep apnea).

In addition, Dr. Cazorla-Lancaster says, "They may have what we call a 'hot potato voice,' where their voice sounds muffled secondary to the tonsils obstructing the airway."

Sleep apnea

According to Yale Medicine, symptoms of sleep apnea in children include:

  • Snoring with gasping between breaths
  • Heavy breathing while sleeping
  • Restless sleep
  • Bedwetting
  • Daytime sleepiness
  • Behavioral problems

Some things can lead to sleep apnea, including excess body weight, enlarged tonsils and adenoids, and Down syndrome or Pierre-Robin syndrome (a congenital disability of the jaw and mouth).

Mouth Breathing Complications

Jill S. Jeffe, M.D., an assistant professor of pediatric otolaryngology at Rush Medical Center in Chicago, says that when children develop sleep apnea, it is almost always due to large tonsils and adenoids.

"If left untreated, sleep apnea can sometimes lead to behavioral problems such as hyperactivity or difficulty paying attention, and also poor growth," she says. The American Thoracic Society attributes slow growth in children to sleep deprivation, which can result in decreased growth hormone released during sleep.

Chronic mouth breathing may also lead to dental problems. According to a 2020 article in Bioinformation, mouth breathing can lead to the following dental issues:

  • Bruxism (teeth grinding)
  • Temporo-mandibular disorder (TMD) of the jaw joints
  • Myofascial pain
  • Teeth erosion
  • Malocclusion (teeth misalignment)
  • Periodontal (gum) disease
  • Cavities
  • Impacted teeth

"Saliva contains many antimicrobial and anti-inflammatory properties," explains Samuel Low, D.D.S., chief dental officer and vice president of dental and clinical affairs at Biolase. "When mouth breathing occurs, it creates dryness of the mouth. As such, with no protection, the decrease of saliva in the mouth allows for more infection and inflammation." As a result, he says that mouth breathing often causes gingivitis, characterized by red or swollen gums.

Treating Mouth Breathing

While the list of potential health hazards associated with mouth breathing might be alarming to some parents, the good news is that most interventions are pretty straightforward. Typically, treatment involves undressing the underlying cause.

In the case of enlarged tonsils or adenoids, a health care provider may recommend surgery. If a child has allergies, then antihistamines might help. Sleep apnea may be helped with continuous positive airway pressure (CPAP). The main thing is not to ignore mouth breathing in children if it doesn't go away.

"If parents are noticing chronic mouth breathing in their children," says Dr. Cazoria-Lancaster, "it should definitely be addressed by their primary care provider."

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