Mouth breathing

Mouth breathing refers to the state of inhaling and exhaling through the mouth.

A healthy individual normally breathes through the nose while resting or doing light exercise, and breathes simultaneously through both the nose and mouth during vigorous aerobic exercise, in order to supply sufficient oxygen. Excessive mouth breathing is problematic because air is not filtered and warmed as much as when inhaled through the nose, as it bypasses the nasal canal and paranasal sinuses, and dries out the mouth. Mouth breathing is often associated with congestion, obstruction, or other abnormalities of the upper respiratory tract. Mouth breathing is a diagnostic sign of adenoiditis especially with persistent rhinorrhea. Comorbidities include asthma, obesity, snoring, halitosis, and obstructive sleep apnea.

Social perception
Mouth breathing in public is sometimes considered to be less socially acceptable or attractive than nose breathing, as mouth breathers can appear to have a somewhat "slack jawed" look, and mouth breathing can cause or exacerbate bad breath. Consequently, the term "mouth breather" may be used in a pejorative sense for someone lacking in hygiene or intelligence.

Buteyko asthma treatment
Mouth breathing may have a role in exacerbating asthma. One of the principle aims of the Buteyko method for the treatment of asthma is to encourage nasal breathing, to the point of actually using paper tape to keep the lips closed.