This is a FACT.
According to many published western clinical studies, mouth breathing is one of 2 leading factors associated with mortality in those severely sick due to chronic diseases.
Studies suggest that the most dangerous moments for “heavy respiration,” or mouth breathing, come in the early morning hours—from about 4 a.m. to 7 a.m. During these predawn and sunrise hours, the death rate is highest from various risk factors such as coronary artery spasms, anginas, strokes, asthma attacks, seizures, and others.
These studies were compiled and analyzed by researchers building on the work of the renowned Dr. Kinstantin Buteyko. Buteyko, who studied breathing patterns during medical school after World War II, observed firsthand the link between respiration and the moment of death.
Mouth Breathing Also Poses Risks to Otherwise Healthy People
Mouth breathing isn’t good for anyone, whether or not they are severely ill or asleep. “The physical, medical, and social problems associated with mouth breathing are not recognized by most health care professionals,” according to a study published in the January/February 2010 issue of General Dentistry, the peer-reviewed clinical journal of the Academy of General Dentistry (AGD). 
Science Daily reported the study, commenting that, “[B]ecause dentists understand the problems associated with mouth breathing, they can help prevent the adverse effects.”
For children, mouth breathing causes problems ranging from improper dental and facial growth to attention deficit disorder and disturbances in behavior, learning, and development. Often, orthodontics and other interventions can be extremely helpful for children who are chronic mouth breathers. “Seeking treatment for mouth breathing can significantly improve quality of life,” says Leslie Grant, DDS.
Otherwise healthy adults can also suffer serious consequences from habitual mouth breathing. According to The Sleep Apnea Information Center (SAIC), mouth breathing at night can lead to….degrading of tissues within the throat…snoring and sleep apnea…headaches…sleep talking…depression…low energy…dry mouth and related dental problems…and many other health effects related to lack of proper oxygenation of the body.
If you aren’t sure whether or not you breathe through your mouth, consider whether your mouth feels dry in the morning or throughout the day. “If there is dryness then breathing through the oral cavity has occurred,” says the SAIC.
Methods to Reverse Mouth Breathing
Dr. Buteyko invented a process involving mouth taping that has helped countless people retrain themselves to breathe through their noses at night. According to the SAIC, the procedure is very simple, and involves only surgical tape and petroleum jelly.
“Cut a strip of the tape 4 inches long and about 1 and a half inches wide. Tape it from below the nose until just on the tip of the chin. Do not tape the mouth entirely because this could be hazardous.” In addition, sleeping sideways as opposed to on the back is said to help significantly.
