According to the Breathing.com, nose breathing has many health benefits, mouth breathing has few. Nose breathing cleans, warms and humidifies the air you breathe, and is associated with increased oxygen extraction from air and decreased heart stress. Mouth breathing, on the other hand, is believed by some researchers to exacerbate asthma, contribute to elevated blood pressure and heart disease and play a role in many other medical problems. Breathing.com suggests that "nose breathing 24 hours a day is extremely important for those who desire the longest and most healthy life."
Cleaning, Warming and Humidifying
The principle function of your nasal passages is to clean, warm and humidify the air you breathe. Lining your nasal passages is a thin layer of protective mucous, which filters 95 percent to 99 percent of dust particles, bacteria, viruses and other airborne objects, according to NormalBreathing.com. When you breathe through your mouth, airborne particles have a more direct path into your alveoli, which are the tiny sacs in your lungs where gas exchange occurs. If pathogens get into your bloodstream, they can stress your immune system and your organs of elimination, such as your kidneys, liver, skin and gastrointestinal tract.
Oxygen Extraction
Your lungs extract oxygen from air primarily during exhalation, according to Breathing.com. Because your nostrils are smaller than your mouth, air exhaled through your nose creates a back pressure, which attenuates air escape so that your lungs have more time to extract oxygen. With optimal oxygen-carbon dioxide exchange, a pH balance is struck in your blood. Oxygen absorption is reduced with mouth breathing--and your blood pH altered--because you blow off carbon dioxide too quickly. The ability of your nasal passages to slow your breathing not only contributes to more oxygen extraction from the air, it also helps reduce stress.
Cardiovascular Health
John Douillard, a chiropractor and proponent of nose breathing for athletes and non-athletes, says humans are designed to breathe through the nose and eat through the mouth, except in those rare instances when access to nasal air simply is not enough. In his book, "Body, Mind, and Sport," Douillard states that nose breathing is important for cardiovascular health at rest and during exercise. "When air enters the body through the nose, it does so in a more refined, rarefied stream," says Douillard, adding that nasal air is more capable of accessing your lung's blood-rich lower lobes than oral air. Air breathed in through your mouth reaches only your lung's middle and upper lobes and contributes to an elevated heart rate, increased stress on the heart and a shorter amount of time that gas exchange can occur in the lungs.
