June 09, 2023 3 min read

Breathing is an unconscious process, which is why most people pay little attention to it. And that’s a shame since the way you breathe can actually have an immense impact on your health and even your sleep.

The human upper respiratory system comprises the nose (with its paranasal sinuses) and the mouth. Most people use both to get air into their lungs and carbon dioxide out. However, some adults and many more children breathe mostly through their mouths. 

While it is easy to see this habit as inconsequential, habitual mouth breathing is considered one of the most harmful oral habits in children [1]. There’s plenty of evidence it leads to health problems in adults as well [2]. Here’s more on how the way you breathe impacts your life.

What Is Mouth Breathing?

Mouth breathing is when you breathe mostly through your mouth. More specifically, it is defined as more than 20 to 35% of air passing through the mouth instead of the nose [3]. It is often caused by an obstruction in the upper airway, such as congestion, a deviated septum, small nostrils, or enlarged adenoids. 

Breathing this way is necessary when you have a congested nose or during strenuous exercise. But when it becomes your default, it can change the structure of your face, impact the quality of your sleep, and affect your health in many other ways. 

While humans do have two air passageways, we were designed to breathe primarily through the nose. The nose is an important part of your respiratory system. When we can’t use it effectively (e.g. due to congestion or injury) is when it’s expected to use the alternative — our mouth. Otherwise, habitual mouth breathing is both a sign something is preventing normal breathing.

Advantages of Nose Breathing

The 19th-century American painter George Catlin wrote a book with a striking title:Shut Your Mouth and Save Your Life. In it, he concluded that the health and vigor of indigenous people of North America were due to nose breathing [4]. Our knowledge of nose breathing is no different today [5]: 

  • The nose acts as an air filter, trapping dust, pollen, and other potentially harmful particles.
  • Inhaling through your nose warms and humidifies air, which keeps your lungs healthy
  • Nose breathing is more efficient, encouraging diaphragmatic breathing in a slow and regular pattern.
  • The nose produces nitric oxide (NO) in the sinuses, which improves cardiovascular health.

Besides that, breathing through your nose is essential for restorative sleep. Breathing this way ensures that air flows normally as you sleep and that your body gets enough oxygen as a result.

Disadvantages of Mouth Breathing

Mouth breathing, on the other hand, is not as beneficial. 

While occasionally necessary, habitual mouth breathing in children has been strongly linked to facial and oral abnormalities, like crossbite, open bite, crossbite, misaligned jaw, long face, and a protruding upper lip, among other things [3].

Mouth breathing during sleep specifically can lead to snoring and even sleep apnea in some cases. Both are signs that the body is not getting enough oxygen during sleep, while sleep apnea also means sleep is seriously disrupted. The low oxygen levels and disrupted sleep can have a deleterious impact on health as many studies show a strong link between sleep apnea and high blood pressure, heart disease, type 2 diabetes, and even depression [6,7]

What to Do About Mouth Breathing

All mouth breathing has an underlying cause, which can often be treated. Congestions due to allergies and viral infections can be treated with medication and air humidifiers. Some children with enlarged adenoids can benefit from surgery as can adults with a deviated septum.

When your mouth breathing leads to snoring or sleep apnea, you may require continuous positive airway pressure (CPAP) therapy to keep your upper airways open. Cases of simple snoring can be treated with a  tongue-stabilizing device and other oral appliances. 


  1. Lin L, Zhao T, Qin D, Hua F, He H. The impact of mouth breathing on dentofacial development: A concise review. Front Public Health. 2022;10:929165. Published 2022 Sep 8.doi:10.3389/fpubh.2022.929165

  1. Jung JY, Kang CK. Investigation on the Effect of Oral Breathing on Cognitive Activity Using Functional Brain Imaging.Healthcare (Basel). 2021;9(6):645. Published 2021 May 29.doi:10.3390/healthcare9060645

  1. Lin L, Zhao T, Qin D, Hua F, He H. The impact of mouth breathing on dentofacial development: A concise review.Front Public Health. 2022;10:929165. Published 2022 Sep 8.doi:10.3389/fpubh.2022.929165

  1. Catlin—Shut Your Mouth.Br Foreign Med Chir Rev. 1870;46(92):435-436.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5163195/

  1. YOUR Guide to Breathing Through The Nose. Physiotherapy for Breathing Pattern Disorders. Accessed June 2023.https://www.physiotherapyforbpd.org.uk/wp-content/uploads/2017/06/YOUR-Guide-to-Nose-Breathing-.pdf

  1. Mannarino MR, Di Filippo F, Pirro M. Obstructive sleep apnea syndrome.Eur J Intern Med. 2012;23(7):586-593.doi:10.1016/j.ejim.2012.05.013

  1. Aloia MS, Arnedt JT, Davis JD, Riggs RL, Byrd D. Neuropsychological sequelae of obstructive sleep apnea-hypopnea syndrome: a critical review.J Int Neuropsychol Soc. 2004;10(5):772-785.doi:10.1017/S1355617704105134

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