No one can live without air as one can without water for a few days and without food much longer. Therefore, nature has surrounded us with air on all sides so that we can get it without any effort.
We take in air through the nose into our lungs. The lungs act as a sort of bellows. The atmospheric air which we breathe in has a life-giving substance – a gas known as oxygen. The air that we breathe out contains poisonous gases. These can kill us if they are not immediately allowed to spread out and get diluted by the atmospheric air. Hence the necessity of proper ventilation.
The air comes into close contact with blood in the lungs and purifies it. Many people do not know the art of breathing. This defect prevents an adequate purification of their blood. Some people breathe through the mouth instead of through the nose. This is a bad habit. Nature has so designed the nose that it acts as a sort of filter for the ingoing air and also warms it. In mouth breathers the atmospheric air reaches the lungs without the preliminary filtration or warming.
It follows therefore that those who do not know how to breathe should take breathing exercises. They are as easy to learn as they are useful. I do not wish to go into a discussion of the various asanas or postures. I do not mean to say that these are not important of useful. But I do wish to emphasize that a well-regulated life is as important as the advantage of studying and practising elaborate postures or exercises. Any comfortable posture that ensures breathing through the nose and free chest expansion is good for our purpose.