Posted by on Oct 25, 2018 in Uncategorized

Chronic mouth breathing

The human mouth was designed for speaking, eating and drinking, whereas the human nose was designed for breathing (and smelling). However, it has been estimated that up to 30-50% of modern adults breathe through the mouth, especially during the early morning hours.

Mouth breathing is common in individuals whose nasal passages are blocked or restricted. A deviated nasal septum or small nostril size can lead a person to breathe through their mouth instead of their nose. However, breathing through the mouth most of the time was not nature’s intention. Many studies have demonstrated that chronic mouth breathing can result in a number of adverse health consequences (see Table 1).


Table 1: Possible Adverse Consequences of Chronic Mouth Breathing

Chronic mouth breathing may contribute to:

  • Introduction of unfiltered, poorly humidified air into the lungs
  • Upper-chest breathing (inefficient and tiring)
  • Chronic over-breathing
  • Greater incidence of snoring and sleep apnoea
  • Bad breath, dental decay, gum disease
  • Dysfunction of the jaw joint (Temporomandibular Joint Disorders)
  • Narrowing of the dental arch, jaw and palate
  • Crowded and crooked teeth
  • Open bite, malocclusion (teeth not fitting together properly)
  • Greater potential for relapse of orthodontic corrections
  • Dysfunctions of the muscles around the jaw and lips
  • Loss of lip tone with the lips becoming flaccid
  • Noisy eating, speech and swallowing problems
  • Trauma to soft tissues in the airways
  • Enlarged tonsils and adenoids

Adapted from Graham T (2012)


According to Jefferson (2010):

“The vast majority of health care professionals are unaware of the negative impact of upper airway obstruction (mouth breathing) on normal facial growth and physiologic health.”

“Children whose mouth breathing is untreated may develop long, narrow faces, narrow mouths, high palatal vaults, dental malocclusion, gummy smiles, and many other unattractive facial features ………….These children do not sleep well at night due to obstructed airways; this lack of sleep can adversely affect their growth and academic performance.”

“Many of these children are misdiagnosed with attention deficit disorder (ADD) and hyperactivity…………………………. If mouth breathing is treated early, its negative effect on facial and dental development and the medical and social problems associated with it can be reduced or averted.”

Mouth breathing adversely affects the way the tongue works. It develops a ‘tongue thrust’. This affects speech, swallowing and chewing. A tongue thrust occurs as a result of the tip of the tongue resting against or between the front teeth, and the tongue is positioned low in the mouth. The tongue should rest in the top of the mouth (with mouth closed) and provide an internal support for the upper jaw.

Mouth breathing plays a critical role in asthma, especially exercise-induced asthma. In a study published in the American Review of Respiratory Disease, young asthma patients had virtually no exercise-induced asthma after exercising while breathing through their noses. However, they experienced moderate bronchial constriction after exercising while mouth breathing.

Mouth breathing results in the mouth becoming dry. This increases the risk of mouth and throat infections. Mouth breathing also results in pollutants and germs being drawn directly into the lungs. Cold and dry air in the airways makes the secretions thick, slows the cleaning cilia, and slows down the passage of oxygen into the blood stream.

Mouth breathing is a typical characteristic of over breathing. When an individual over breathes, too much carbon dioxide is lost from the blood and this results in reduced oxygenation of tissues and organs. In contrast, when breathing volume is reduced towards normal, through nose breathing, higher carbon dioxide in the blood decreases the affinity between oxygen and haemoglobin, resulting in greater oxygenation of tissues and organs.

There is little awareness and understanding within the medical profession of the adverse health implications of chronic mouth breathing. A conscious effort to ensure that people predominately nose breathe would likely result in a healthier population and a resultant decrease in healthcare expenses. The earlier chronic mouth breathing is identified the easier it is to change to nose breathing. Such a change can be facilitated by breathing retraining using the Buteyko Breathing Method.

Below, you can access a short 3 minute video which explains how chronic mouth breathing can result in abnormalities of the teeth and the upper and lower jaws.