Breathing provides your body with the oxygen it needs to survive. It also allows you to release carbon dioxide and waste.

You have two air passageways to your lungs — the nose and the mouth. Healthy people use both their nose and their mouth to breathe.

Breathing through the mouth only becomes necessary when you have nasal congestion due to allergies or a cold. Also, when you are exercising strenuously, mouth breathing can help get oxygen to your muscles faster.

Even so, breathing through the mouth all the time, including when you’re sleeping, can lead to problems.

In children, mouth breathing can cause crooked teeth, facial deformities, or poor growth. In adults, chronic mouth breathing can cause bad breath and gum disease. It can also worsen symptoms of other illnesses.

The importance of your nose often goes unnoticed — until you have a bad cold. A stuffed-up nose can reduce your quality of life. It can also affect your ability to sleep well and function in general.

The nose produces nitric oxide, which improves your lungs’ ability to absorb oxygen.

Nitric oxide increases the ability to transport oxygen throughout your body, including inside your heart. It relaxes vascular smooth muscle and allows blood vessels to dilate.

Nitric oxide is also antifungal, antiviral, antiparasitic, and antibacterial. It helps the immune system to fight infections.

Advantages of nose breathing

  • The nose acts as a filter and retains small particles in the air, including pollen.
  • The nose adds moisture to the air to prevent dryness in the lungs and bronchial tubes.
  • The nose warms up cold air to body temperature before it gets to your lungs.
  • Nose breathing adds resistance to the air stream. This increases oxygen uptake by maintaining the lungs’ elasticity.

You may not realize that you’re breathing through your mouth instead of your nose, especially while you sleep. People who breathe through their mouth at night may have the following symptoms:

Symptoms in children

For parents, it’s important to look for signs of mouth breathing in their children.

A child may not be able to communicate their symptoms. Like adults, children who are mouth breathers will breathe with their mouth open and will snore at night. Children who breathe through their mouths for most of the day may also have the following symptoms:

  • slower than normal growth rate
  • irritability
  • increased crying episodes at night
  • large tonsils
  • dry, cracked lips
  • problems concentrating at school
  • daytime sleepiness

Children who exhibit problems concentrating at school are often misdiagnosed with attention deficit disorder (ADD) or hyperactivity.

The underlying cause of most cases of mouth breathing is an obstructed (completely blocked or partially blocked) nasal airway.

In other words, there’s something preventing the smooth passage of air into the nose. If your nose is blocked, the body automatically resorts to the only other source that can provide oxygen — your mouth.

There are many causes of a blocked nose. These include:

Some people develop a habit of breathing through their mouth instead of their nose even after the nasal obstruction clears. For some people with sleep apnea, it may become a habit to sleep with their mouth open to accommodate their need for oxygen.

Stress and anxiety can also cause a person to breathe through their mouth instead of their nose. Stress activates the sympathetic nervous system leading to shallow, rapid, and abnormal breathing.

Anyone can develop a habit of breathing through their mouth, but certain conditions increase your risk. These include:

There’s no single test for mouth breathing. A doctor might diagnose mouth breathing during a physical examination when looking at the nostrils or during a visit to find out what’s causing persistent nasal congestion. They may ask questions about sleep, snoring, sinus problems, and difficulty breathing.

A dentist may diagnose mouth breathing during a routine dental examination if you have bad breath, frequent cavities, or gum disease.

If a dentist or doctor notices swollen tonsils, nasal polyps, and other conditions, they may refer you to a specialist, like an ear, nose, and throat (ENT) doctor for further evaluation.

Mouth breathing is very drying. A dry mouth means that saliva cannot wash bacteria from the mouth. This can lead to:

Mouth breathing may result in low oxygen concentration in the blood. This is associated with high blood pressure and heart failure. Studies show mouth breathing may also decrease lung function, and worsen symptoms and exacerbations in people with asthma.

In children, mouth breathing can lead to physical abnormalities and cognitive challenges. Children who aren’t treated for mouth breathing can develop:

  • long, narrow faces
  • narrow mouths
  • gummy smiles
  • dental malocclusion, including a large overbite and crowded teeth
  • poor posture

Additionally, children who breathe through their mouths often don’t sleep well at night. Poor sleep can lead to:

  • poor growth
  • poor academic performance
  • inability to concentrate
  • sleep disorders

Treatment for mouth breathing depends on the cause. Medications can treat nasal congestion due to colds and allergies. These medications include:

Adhesive strips applied to the bridge of the nose can also help breathing. A stiff adhesive strip called a nasal dilator applied across the nostrils helps decrease airflow resistance and helps you breathe more easily through your nose.

If you have obstructive sleep apnea, your doctor will likely have you wear a face-mask appliance at night called continuous positive air pressure therapy (CPAP).

A CPAP appliance delivers air to your nose and mouth through a mask. The pressure of the air keeps your airways from collapsing and becoming blocked.

In children, surgical removal of swollen tonsils and adenoids can treat mouth breathing.

A dentist might also recommend that your child wears an appliance designed to widen the palate and help open the sinuses and nasal passages. Braces and other orthodontic treatments might also help treat the underlying cause of mouth breathing.

Treating mouth breathing in children early can reduce or prevent the negative effect on facial and dental development. Children who receive surgery or other intervention to reduce mouth breathing show improvement in energy levels, behavior, academic performance, and growth.

Untreated mouth breathing can lead to tooth decay and gum disease. Poor sleep caused by mouth breathing can also reduce your quality of life and exacerbate stress.

Chronic mouth breathing caused by the shape of your face or nose can’t always be prevented.

If you find that your nose is frequently congested due to allergies or respiratory infections, there are actions you can take to prevent making mouth breathing a habit. It’s a good idea to address nasal congestion or dryness right away. Tips for preventing mouth breathing include:

  • using a saline mist during long flights or cruises
  • using saline nasal mists and sprays and nasal decongestants or allergy reliever medications at the first sign of allergy or cold symptoms
  • sleeping on your back with your head elevated to open up the airways and promote nasal breathing
  • keeping your house clean and free of allergens
  • installing air filters in your heat and air conditioning (HVAC) systems to prevent the spread of allergens in your house
  • consciously practicing breathing through your nose during the day to help force yourself into a habit of nose breathing

If you’re experiencing stress or anxiety, it may help to engage in yoga or meditation practice.

Yoga is beneficial for people who breathe through their mouths as a result of stress because it focuses on deep breathing through the nose.

Restorative yoga is designed to activate the parasympathetic nervous system and promote slower deep breathing through the nose.