Importance of Breathing Through The Nose
The first rule for correct breathing is that we should breathe through the nose. This may seem obvious, but many people breathe principally through the mouth. Mouth breathing can adversely affect the development of the thyroid gland. It can retard the mental development of children.
The nose has various defense mechanisms to prevent impurities and excessively cold air entering the body. At the entrance to the nose, a screen of hairs traps dust, tiny insects and other particles that may injure the lungs if you breathe through the mouth. After the entrance of the nose, there is a long winding passage lined with mucus membranes, where excessively cool air is warmed and very fine dust particles that escaped the hair screen are caught. Next, in the inner nose are glands which fight off any bacilli which have slipped through the other defenses. The inner nose also contains the olfactory organ-our sense of smell. This detects any poisonous gases around that may injure our health.
The yogis believe that the olfactory organ has another function: the absorption of prana from the air. If you breathe through the mouth all the time, as many people do, you are cheating yourself of all this free energy (prana). The yogis say this is a major factor in lowered resistance to disease and impairs the functioning of your vital glands and nervous system. Add to this the fact that pathogens can enter the lungs via mouth breathing, and you can see2