Mouth Breathing: Causes, Symptoms, Effects and How to Stop It

Healthy, efficient breathing happens through the nose. But if your nose is blocked, or your tolerance to carbon dioxide is very low, it is likely you habitually open your mouth to breathe.

As many as 90% of us have a deviated nasal septum, where the cartilage between the nostrils is crooked. Children often experience swollen adenoids and tonsils that block the nasal airway. A sedentary lifestyle, poor cardiovascular fitness, and misconceptions about breathing all play their part.

If you breathe through an open mouth during exercise, while sleeping, or just by force of habit, you may be surprised by the damage it can cause. If your child is a mouth breather, the consequences are perhaps even more serious.

This article covers the causes, symptoms and effects of mouth breathing in adults and children, and explains how to fix it.

What Is Mouth Breathing?

Mouth breathing is a dysfunctional breathing pattern, related to stress and disease states. If you notice yourself breathing through your mouth almost all the time, or you are a nighttime mouth breather, there are steps you can take to restore healthy breathing.

While mouth breathing is normal if you have a heavy cold or are exercising intensively, chronic mouth breathing indicates a problem.

Whether mouth breathing is the cause or result of your symptoms, breathing re-education to restore nasal breathing will help you feel better and perform better. In children, it is essential for healthy growth of the face, teeth, airways, and brain.

What Causes Mouth Breathing?

Mouth breathing can be caused by anything that puts your body and your breathing out of balance. Some causes may not be immediately obvious. Here are just a few reasons you may be breathing through your mouth:

• Asthma
• Allergies
• A deviated nasal septum or other physical nasal obstruction
• Chronic colds or airway infections
• Swollen or enlarged tonsils and/or adenoids
• Polyps in your sinuses
• A history of thumb or finger-sucking
• A history of childhood mouth breathing
• A small nose
• Birth abnormalities including cleft palate, tongue-tie, and lip-tie [1]
• Down syndrome
• Poor posture, especially if you sit in front of a computer all day or drive professionally
• Emotional stress, panic disorder and/or anxiety
• Extra resistance to breathing caused by your face mask
• Bottle feeding or overuse of a pacifier in infancy [2,3]

Habitual mouth breathing will itself cause more mouth breathing. If you are already a mouth breather, it is likely your nose is too congested to breathe through.

At night, mouth breathing can happen as you get older. Once you reach the age of 40, you are 60% more likely to spend at least half the night breathing through an open mouth [4]. In postmenopausal women, the risk of sleep apnea increases by 200% compared with women who are still menstruating [5].

Extra weight around the tongue, neck and belly can cause mouth breathing during sleep. So can sleeping on your back, an overheated room, drinking alcohol before bed, and eating late.

Is Mouth Breathing Bad?

Mouth breathing is often fast, hard, audible and involves visible movement of the upper chest. Sometimes it is punctuated by heavy sighs. You would expect to see this type of breathing in someone who is very stressed or breathless.

For habitual mouth breathers, the negative side effects become chronic, due in part to over-breathing or hyperventilation. Hyperventilation is defined as breathing too much air, reducing levels of blood carbon dioxide below normal. Long term, mouth breathing has a serious negative impact on health and longevity, and even on the way your face looks.

Mouth Breathing Symptoms: What to Look Out For

"Back in 1909, an article, Habitual Mouth-Breathing and Consequent Malocclusion of the Teeth, was published in The Dental Cosmos. In it, DeLong described how mouth-breathing can cause the sleeper to wake with a dry mouth and throat in the morning, often accompanied by headache:

A restless sleep, and much tossing in bed and snoring will be observed. The face is usually elongated, the bones of the face are underdeveloped, as the air spaces do not have the proper circulation, the nostrils are small.

DeLong goes on to list other detrimental effects of mouth breathing, including recession of the chin and a high narrow palate with crooked teeth. Children who breathe through their mouths are observed as looking dull and expressionless and may be accused by their teachers of being inattentive in class." — The Breathing Cure, Patrick McKeown

For adults, you may notice you can hear your breathing. Maybe you make a lot of noise when you eat, because you struggle to eat and breathe at the same time. You are likely to have bad breath [6].

Mouth breathing dries the saliva, creating a breeding ground for the bacteria that cause halitosis and tooth decay. You may frequently have a blocked, stuffy, or runny nose.

When you exercise, you are more likely to experience exercise-induced asthma, as cold, dry air hits your airways. You will also get colds and respiratory infections more often. Mouth breathing and a sore throat often go hand in hand, due to irritation, inflammation, and dehydration of the airway.

Long-term, mouth breathing is linked with high blood pressure, greater risk of cardiovascular disease, and stress-related problems including anxiety, panic attacks and insomnia. It also reduces immunity to airborne viruses, allergens and bacteria. Mouth breathing and anxiety create a vicious cycle.

Fast, dysfunctional breathing can make you anxious, and anxiety causes fast hard breathing. When breathing is fast and hard, blood CO2 levels drop. People prone to panic disorder are known to have lower-than-normal levels of blood CO2 [7].

During sleep, mouth breathing is likely to cause snoring or even sleep apnea, a serious disorder in which breathing stops periodically during the night. This leads to oxygen desaturation and contributes to daytime fatigue, road traffic accidents [8] and early mortality.

If you treat sleep apnea with CPAP, mouth breathing is the leading cause of non-compliance, as air meant to support the airway leaks out through the lips [9].

The Effects of Mouth Breathing on the Face, Chin and Jaw

If you are a mouth breather, especially since childhood, you will have a particular mouth breathing face shape. Mouth breathing affects the development of the face, jaw, and teeth when you are still growing.

This is partly due to the downward pull of gravity on the face, and partly to the incorrect resting position of the tongue. The tongue plays an important role in facial growth, and it can only sit in its correct place when the mouth is closed.

As an adult you may notice your nose is bent, the lower part of your face is elongated, your chin is recessed, and your teeth and tongue do not seem to fit in your mouth. 

Your teeth are likely to be crowded and/or crooked, and you may have heavy bags under your eyes. You may also experience neck and back pain and poor posture because you constantly push your head forward to breathe.

Does mouth breathing change your face? Over time, yes, it does. Mouth breathing has undeniable effects on the shape of the face.

How to Fix Mouth Breather Face

The first step in fixing the problem is to learn to breathe through your nose. Use breathing exercises and open your nose with a nasal dilator. You can also explore myofunctional therapy, which strengthens muscles in the tongue and throat, helping to restore proper function.

Chronic mouth breathing in children can negatively affect skull and facial development and restrict the airways. If you breathed through an open mouth as a child, you may need dental surgery to expand your jaw, open your airway and give your teeth the space they need.

By age six, nearly 60% of the adult face has developed. Learning good nasal breathing early in life is essential to maximise the growth and development of the skeletal complex, the upper airway and to prevent mouth breather face.

Mouth breathing in children has been attributed to genetic factors, unhealthy oral habits, and blocked nasal airways.

Blocked or obstructed nasal airways can be caused by enlarged adenoids, tonsils, and nasal concha. Risk factors include allergic rhinitis, nasal or facial deformities, or foreign bodies [26].

Other factors that can cause mouth breathing include cigarette smoking, neuromuscular disorders and congenital issues like Ehlers-Danlos Syndrome (EDS) and dental agenesis.

Does Mouth Breathing Change Your Face?

In simple terms, yes. Mouth breathing causes abnormal growth that affects teeth, the face, the skull, breathing, chewing, speech and more.

Mouth breather faces tend to be narrower and longer with a receding jaw and a restricted airway. The tongue is also positioned downward due to mouth breathing [30].

Medical studies show that mouth breathing changes muscle recruitment in the upper airway. These changes alter correct growth of the face and lead to abnormal facial growth that can be easily observed.

In experiments where rhesus monkey noses were plugged to force mouth breathing, skeletal, dental, and soft tissue changes occurred, including changes to the function and posture of the mandible, tongue, and upper lip [31].

At six months, the monkeys' noses were unblocked. Normal nasal breathing returned, with improved face, teeth and skull development [29].

Adenoids are the most common cause of upper airway blockage in children. This obstruction affects dental and facial development, causes mouth breathing and leads to "adenoid face" [30].

Nasal airway obstruction due to adenoids and/or tonsils can also cause sleep issues including mouth breathing, snoring or even severe obstructive sleep apnea [27]. 

One study observed poorer school performance in children with enlarged adenoids, thought to be due to the relationship between hypoxia during sleep and brain function [30].

Treatments: Can Mouth Breathing Face Be Reversed in Adults?

Most facial and skull development is finished by the time we leave childhood. But before considering surgery, which in adulthood will be significant, it is worth trying a gentler approach.

Nose Breathing

For adequate face and airway development, the ultimate goal should be permanent nose breathing. Use breathing exercises and open your nose with a nasal dilator. Addressing mouth breathing during sleep is essential.

Newborns spend nearly 80% of their time asleep. Even at six years of age, children can spend 25% of the day asleep. Nasal breathing during sleep stimulates ventilation and active reflexes which help maintain the muscles that stabilise the upper airway [28].

Myofunctional Therapy

You can also explore myofunctional therapy, which strengthens muscles in the tongue and throat, helping to restore proper function. Myofunctional therapy has been used in muscular dystrophy to help with proper bone growth and to correct speech issues in young children. Improving the muscle function of specific airway muscles may improve the function and growth of the upper airway [29].

Rapid Palatal Expansion (RPE)

Orthodontists perform RPE to improve obstructive sleep apnea in children by reducing airway resistance, increasing nasal volume and raising tongue posture. Rapid palatal expansion is not advisable for adults.

RPE has also been shown to modify and improve facial structure in children. In a study on the impact of rapid palatal expansion on adenoid and tonsil sizes, 90% of patients had significantly reduced adenoids and 97.5% had a reduction in tonsil size [27].

Key Findings: Mouth Breathing, Posture and Facial Development

Oral or mouth breathing is an important clinical symptom which may be associated with palatal growth restriction, nasal obstruction, and musculoskeletal dysfunction [29].

Treatment of nasal obstruction in children leads to normal dentofacial development. Early detection is vital to prevent mouth breathing face [30]. Muscle strengthening should also be included as an additional tool to encourage optimal craniofacial growth [29].

Mouth Breathing and Forward Head Posture

For most people, modern life dictates that we spend many hours sitting down, often peering at a screen. It is easy to slump and allow the head to thrust forward.

To fix your posture, you must first correct your mouth breathing. When you mouth breathe, it is impossible for the tongue to rest in its proper position. Your airway becomes dry and inflamed and your nose blocks. Habitual mouth breathers push their heads forward to compensate for restricted airways.

Over time, this forward thrust of the head causes pain and muscle fatigue. The average head weighs around 11 pounds. Every inch of forward head posture increases the weight on the spine by around 10 pounds.

Mouth breathing is also self-perpetuating. It tends to be shallow, into the upper chest instead of from the diaphragm. When posture is poor, the diaphragm becomes squashed. If the diaphragm cannot move properly, you cannot breathe deeply.

The diaphragm is integral to core and spinal stabilisation. It is closely linked with balance. Poor diaphragm function contributes to back pain and injury. When the diaphragm cannot move freely, we breathe into the chest.

Chest breathing activates the fight or flight stress response and changes blood CO2 levels, which changes the acidity of the blood. Combined with stress, this contributes to painful myofascial trigger points and muscle aches.

During chest breathing, smaller breathing muscles mobilise to help get air into the body. These include muscles in the neck called the scalenes. If the diaphragm is not doing its job, the scalenes have to work too hard. Compensatory use of the scalene muscles causes neck pain and compromises the cervical range of movement.

Take a moment to notice. Are you slumped at your desk, or sitting up straight? Try pushing your head forward and opening your mouth. Notice your breathing. Can you breathe comfortably from your diaphragm, or is your breathing forced?

Now gently line up your spine so your head, heart and pelvis are balanced over each other. Close your lips and let your tongue rest in the roof of your mouth. Feel your neck relax and your mind calm.

Patrick explains the role of mouth breathing in forward head posture, and why it is important to address children's mouth breathing early.

What the Scientists Say about Mouth Breathing

Here is a summary of clinical studies on mouth breathing, forward head posture and impaired lung function.

Mouth breathing and forward head posture: effects on respiratory biomechanics and exercise capacity

Sabatucci A et al. Minerva stomatologica. 2015;64(2):59-74.

"Our study confirms that oral breathing modifies head position. The significant increase of the craniocervical angles NSL/OPT and NSL/CVT in patients with this altered breathing pattern suggests an elevation of the head and a greater extension of the head compared with the cervical spine."

What does it mean? Breathing through the mouth causes measurable changes to head position.

Relationship between mouth breathing and postural alterations of children

Krakauer LH, Guilherme A. International Journal of Orofacial Myology. 2000;26:13-23.

This review demonstrates that children aged 8 and over with nasal respiration have better posture than those who continue oral breathing beyond the age of 8.

What does it mean? Mouth breathing in children should be corrected as soon as possible to avoid detrimental postural changes.

Exercise capacity, respiratory mechanics, and posture in mouth breathers

Okuro RT et al. Braz J Otorhinolaryngol. 2011;77(5):656-62.

Brazilian researchers at Campinas State University assessed exercise tolerance, breathing muscle strength and body posture in 107 children, of whom 45 were mouth breathers and 62 were nasal breathers. Examination revealed that 80% of mouth breathing children had abnormal cervical posture and breathing pattern.

Researchers concluded that "mouth breathing children had cervical spine postural changes and decreased respiratory muscle strength compared with nasal breathing."

What does it mean? Habitual mouth breathing is associated with postural changes resulting in decreased muscle strength, reduced chest expansion and impaired breathing.

Mouth breathing and forward head posture: effects on respiratory biomechanics and exercise capacity in children

J Bras Pneumol. 2011;37(4):471-9.

Scientists evaluated submaximal exercise tolerance and respiratory muscle strength in 92 children aged 8 to 12 years. The study concluded that respiratory biomechanics and exercise capacity were negatively affected by mouth breathing.

What does it mean? Mouth breathing causes the breathing muscles, primarily the diaphragm, to become weak. When breathing is inefficient, you will become exhausted more quickly during exercise.

Assessment of the body posture of mouth-breathing children and adolescents

Conti PB et al. J Pediatr (Rio J). 2011;87(4):357-63.

A study of 306 mouth breathing and 124 nasal breathing children showed that "postural problems were significantly more common among children in the group with mouth breathing syndrome." Researchers noted that boys are more likely to be mouth breathers than girls.

What does it mean? Mouth breathing is present in around 50% of children. Children who are mouth breathers are likely to experience postural problems that can persist into adulthood.

Orientation and position of head posture, scapula, and thoracic spine in mouth-breathing children

Neiva PD et al. Int J Pediatr Otorhinolaryngol. 2009;73(2):227-36.

This study found that "mouth breathing children increased scapular superior position in comparison to nasal breathing children due probably to the position of forward head, leading to an alteration in the positioning of the mandible."

What does it mean? Reliable measurement is important when assessing postural changes in children with oral breathing, to help physical therapists focus rehabilitation strategies effectively.

Why Do I Sleep with My Mouth Open?

Age, extra weight, lazy airway muscles, sleeping on your back, and alcohol before bed are among the many reasons your mouth may fall open during sleep. When you are unconscious, it is difficult to maintain control over your muscles.

If your breathing is a little hard and fast during the day, it is likely you will mouth-breathe at night. Daytime mouth breathing may even prevent you from getting to sleep at all, as it causes hyperarousal of the sympathetic nervous system that contributes to insomnia [10].

Is it Bad to Sleep with Your Mouth Open?

Mouth breathing while sleeping leads to loud snoring and makes symptoms of sleep apnea much worse [11]. Sleep apnea is linked with depression, death by road traffic accident, sudden cardiac death, cardiac arrhythmias, and erectile dysfunction in men.

How to Stop Mouth Breathing While Sleeping

To stop mouth breathing at night, you need to stop sleeping with your mouth open. To keep your mouth closed, you can practice breathing exercises that reduce the speed and flow of air you breathe.

You can also try myofunctional therapy to strengthen the muscles of your tongue and throat. Some people use a chin strap, but this can cause pain in the temporomandibular joint in your jaw. If you want to keep your mouth closed while sleeping without discomfort, use a lip tape like MyoTape.

To find out more about the benefits of breathing re-education for sleep apnea, read Patrick McKeown's review in the Journal of Clinical Medicine and check out our online sleep course.

According to Dr. Christopher Winter, medical director of the Martha Jefferson Hospital sleep medicine centre in Charlottesville, Virginia: "There are athletes everywhere who have sleep apnea. Not only does the apnea affect their athletic performance, but it is extremely hard on their cardiovascular systems as well."

In a study published in The New England Journal of Medicine, the prevalence of sleep-disordered breathing among professional NFL players was reported as 14% overall, and 34% among offensive and defensive linemen [12].

Breathing through the nose in a quiet, gentle manner during sleep reduces snoring and obstructive sleep apnea. Snoring occurs due to a large volume of air passing through a narrowed space, causing turbulence in the soft palate, nose or back of the throat.

If you snore, there are two factors at play. The first is that you are breathing too hard during sleep. The second is that your nose may be congested, causing the upper airways to become narrow. Simply by unblocking the nose, switching to nasal breathing, and calming breathing towards normal, snoring and sleep apnea greatly reduce.

Upper airway resistance is much higher when breathing through the mouth during sleep. Obstructive apneas and hypopneas are profoundly more frequent when breathing is through the mouth [13], and oxygen desaturation is much worse.

According to the late Dr. Christian Guilleminault of Stanford University: "The case against mouth breathing is growing, and given its negative consequences, we feel that restoration of the nasal breathing route as early as possible is critical" [14].

At Oxygen Advantage we advocate mouth taping to ensure nasal breathing during sleep. A 2020 article on nasal nitric oxide and COVID-19 noted that "favouring nasal breathing during sleep by sealing the mouth with adhesive tape reduces common colds. This phenomenon may be due to the filtration and humidifying effects of the nose on inhaled air and to increased NO levels in the airways, which may decrease viral load during sleep and allow the immune system more time to mount an effective antiviral response" [15].

Athletes are susceptible to colds and respiratory infections, causing missed training days and missed competition — yet another reason to ensure you breathe through your nose at night.

Should I Tape My Mouth Shut at Night?

Yes. It is the best way to ensure nasal breathing when you are asleep. However, before you try taping, follow these simple guidelines:

• Never tape your mouth if you feel nauseous or may vomit.
• Do not tape your mouth at night if you have been drinking alcohol or taken recreational drugs.
• Only tape your mouth using a specialist lip tape or Micropore paper tape. Never use tape with strong adhesive or glue not designed for the skin.
• If you are anxious about taping, try MyoTape. It goes around the mouth rather than over the mouth, so you can still open your mouth if you need to. This makes it incredibly safe.
• Always read the instructions on the packet before applying lip tape.
• If you have any concerns or a serious medical condition, consult your medical doctor before taping your mouth to sleep. If in doubt, you can also find a certified breathing instructor to help.
• Always listen to your body.

How to Stop Mouth Breathing in My Child

Mouth breathing in children is a serious matter. Left unchecked, it can cause irreversible changes in facial growth and cognitive ability [16], and it contributes to behavioural disorders including ADHD [17]. In small babies, mouth breathing has been linked with sudden infant death syndrome [18].

Here are a few signs that mouth breathing may be impacting your child:

They have dental problems

Does your child have crowded teeth, dental pain, smelly breath, jaw pain, or an irregular bite? Mouth breathing causes changes in the growth of the teeth and jaws.

When the tongue sits in its correct resting position (in the roof of the mouth just behind the front teeth), it helps the jaw and palate to grow wide, with nice straight teeth. During mouth breathing, the tongue cannot fulfil this function.

They constantly have a blocked nose

When a child has swollen adenoids and/or tonsils, they may resort to mouth breathing because they cannot breathe through the nose. Many parents resort to surgery, but this is not always necessary. Swollen adenoids and tonsils are aggravated during mouth breathing and may resolve when nasal breathing is restored. If your child does have surgery, it is vital to teach them to breathe through the nose after the procedure.

Removing the adenoids and tonsils can significantly reduce symptoms of sleep apnea, but one study found it only completely resolved the problem in 27% of cases [19].

This indicates other causative factors are present. Another study found that if nasal breathing is not restored, sleep apnea will recur within 3 years of surgery [20].

They have sleep-disordered breathing, snoring or sleep apnea

"Studies have defined the risk factors of obstructive sleep apnea in children as a narrow palate, long face, enlarged tonsils and/or adenoids, and minor malocclusions, and not, as some might expect, obesity." — The Breathing Cure, by Patrick McKeown

In his 2021 bestseller, Oxygen Advantage founder Patrick McKeown argues that dentists should be involved in identifying sleep-disordered breathing in children. Between 1 and 5% of children have sleep-disordered breathing, and the condition has been linked with sudden infant death syndrome [21].

No child should ever snore. If your child snores regularly, it warrants investigation.

They have speech changes and auditory processing disorders

Mouth breathing can cause speech disorders. If your child lisps or is slower developing speech and language than expected, it may be down to mouth breathing [22,23,24]. Mouth breathing can also cause a hoarse-sounding voice due to dry airways.

You may notice changes in the shape of the jaw and chin

Children who are mouth breathers will display changes in the jaw. The face and lower jaw are likely to become longer. The child may develop an overbite and a receding chin.

Your child may struggle to focus at school or display behavioural issues

If your child habitually breathes through their mouth, less oxygen will get to the brain and sleep will be disturbed. Studies have linked mouth breathing and sleep-disordered breathing with a permanent reduction in cognitive ability, special educational needs, and ADHD.

To read more about the dangers of mouth breathing in children, visit our sister site ButeykoClinic.com.

How to Stop My Child Mouth Breathing

MyoTape is available in a small size that is ideal for children and teens. It can be worn by any child aged 4 years and older who is able to easily remove the tape themselves.

Treatment for mouth breathing is largely a matter of retraining the habit of nose breathing. Observe when your child breathes through their mouth. Notice how they breathe when watching TV or concentrating on homework.

You can use MyoTape for short periods during the day as well as at night. You may like to work with a breathing instructor to help. Or try the free program of children's breathing exercises on the Buteyko Clinic website.

To stop mouth breathing, see our online breathing course, to train others, become a certified breathwork instructor, or find an Oxygen Advantage instructor near you.

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