Normal breathing is done through the nose. Each nostril functions independently and synergistically to filter, warm, moisturize, dehumidify and smell the air.
Babies are born obligate nose breathers, but somewhere along the way nose breathing can change to mouth breathing, with dire consequences. The most obvious adverse effect of mouth breathing is dryness of the oral and pharyngeal tissues, leading to inflamed tonsils, tonsil stones, dry cough, swollen tongue, halitosis, gingivitis and caries.
Normal respiration follows a gentle wave pattern with 10 to 12 breaths per minute. Mouth breathers take too many breaths, with rates from 12 to 20 breaths per minute or more. Breathing delivers oxygen to the cells of the body and removes excess carbon dioxide. Carbon dioxide is produced as a byproduct of exercise and digestion of food. Carbon dioxide plays a significant role in the release of oxygen from hemoglobin. It also triggers breathing, maintains blood pH and prevents smooth muscle spasms. All of these functions are reduced or impaired in mouth breathers.