The nose and the mouth serve very different functions. Each nostril is innervated by five cranial nerves from a different side of the brain. Each nostril functions independently and synergistically in filtering, warming, moisturizing, dehumidifying, and smelling the air. It's like having two noses housed in one shelter. They meet at the nasopharynx of which Vernon Gray, M.D. calls the "garbage disposal" because this is where the mucous are accumulated and produced by the goblet cells. The respiratory system of carbon dioxide and oxygen exchange occurs in the alveoli of the lungs. When there is proper oxygen-carbon dioxide exchange, the blood will maintain a balanced pH. If carbon dioxide is lost too quickly, as in mouth breathing, oxygen absorption is decreased. There is a negative pressure built in the lungs, thereby decreasing the blood absorption of oxygen. Because the breathing mechanism (nerve innervations) is situated in the nose and not in the mouth, the brain thinks carbon dioxide is being lost too quickly through the nose. The brain sensing this, will stimulate the goblet cells to produce mucous and slow the breathing. Konstantine Buteyko, M.D. has discovered that when carbon dioxide is held longer in the lungs, the alveoli would relax. It would result in the increase of oxygen absorption in the blood. The Buteyko Breathing Technique encourages inhaling and exhaling through the nose. Dr. Buteyko claims that when there is sufficient carbon dioxide in the blood, the oxygen molecules will release more freely to all the cells of the body. The Buteyko practitioners, in many cases, claim the need for medication for asthmatic patients is reduced due to the greater efficiency of the naturally relaxed alveoli. Dr. Jon Lundberg, a physician at the Department of Physiology and Pharmacology, Karolinska Institute in Stockholm discovered the paranasal sinuses are powerful producers of nitric oxide (NO). Although this gas is considered a pollutant in the atmosphere, in small doses, it is lethal to bacteria and viruses. The sinuses are moist, warm, and bacteria-friendly. They should be perfect places for bacteria to live. He believes it is the nitric oxide that keeps the sinuses sterile. He found that nitric oxide is a strong vasodilator, a substance that dilates blood vessels. Since the sinuses create high concentration of NO, when we breathe through our noses, NO travels down the airway to the lungs. Dr. Lundberg shows that arterial oxygenation increases during nasal breathing compared to oral breathing. Doctors already use NO to open the blood vessels of patients on ventilators suffering from high blood pressure. Dr. Lundberg found that he can increase the oxygen content of his patients' blood by 25 percent by simply pumping their own nasal air into their ventilators. The role of nitric oxide (NO) in respiration, Dr. Lundberg states, would increase the amount of oxygen in the blood. Steven K. Sue, D.D.S., M.S., Inc. Honolulu, HI USA Tel. (808) 949-8876