Abstract
Mouth breathing is a sign associated with Sleep and Breathing related Disorders and Obstructive Sleep Apnea in children. The aim of this paper is to provide a comprehensive overview of the changes in the human physiology when mouth breathing and, how it may affect the oral and general health in humans. The potential reactions produced at the cellular level and, how those reactions may lead to a negative impact in the human health are presented. Mouth breathing affects the O2/CO2 exchange at the lungs, which may lead to the production of the Hypoxia Inducible Factor (HIF) in all the cells in the human body, as well as stimulates the production of Erythropoietin in the kidney. Mouth breathing also causes a major loose of CO2, which increases the production of bicarbonates in the kidney and release of essential minerals through the urine. All those reactions may facilitate the development and progression of chronic diseases in humans. It is recommended to consider mouth breathing as an oral habit that may associate with a cascade of events in the human physiology leading to chronic health problems. The health professionals should consider mouth breathing as a health risk factor and treat it as early as possible.