Normal breathing is generally unconscious, i.e. it requires no special attention on our part, but inclusion of deep breathing exercises in our routine can do wonders in improving as well as maintaining a Great Health. There is a famous phrase which says: “Hundred deep-breaths in a day” is one physician’s recipe for avoiding Tuberculosis. A Russian author, who suffered a nervous breakdown, employed many other aids for curing his disease, but all failed, and ultimately simple deep breathing exercises, practiced systematically everyday, resulted a permanent cure to his devastating disease.

1. Deep Breathing enhances Lung Capacity: The lungs, like every other part of the body, become weakened when not used. Shallow breathing causes degeneration of lung tissue, and indirectly degeneration of every tissue in the body, which reduces the capacity of Red Blood Cells to carry enough oxygen to maintain health. Shallow breathers only use the upper parts of the lungs.It is not to be wondered at that the lower parts of the Lungs generally degenerate first. In pneumonia, for instance, the lower part is usually first affected, and in Tuberculosis one often can get the physical indications in the lower part of the lungs posteriorly before they are found in any other place. It is the upper parts of the lungs that generally come in use i.e. why they get more exercise and more blood and hence become more resistant. It is well known fact that when the upper part of the lungs becomes affected, then the disease is very severe. The chest enlarges during inspiration, and no constriction should be allowed to prevent the free movement of the Chest. 
2. Deep Breathing benefits to Other Organs: Deep breathing must be abdominal, but must be slow and rhythmic. Such breathing is always health-imparting. It massages the liver gently and act as a  mild tonic to the stomach and the bowels. It also helps to prevent constipation.
3. Deep Breathing Enhances Activeness: Many people are guilty of shallow breathing. Such people are generally inactive and their breathing becomes sluggish. Simple remedy for this is to take deep breathing exercises, especially in open air.
4. Deep Breathing Improves Blood Circulation in Body: In ordinary breathing, only about 10 % of the lung contents are exchanged at each breath. But In deep breathing a much larger percentage is exchanged. In Deep Breathing, the whole lung comes into action, and the circulation of the blood in the abdomen is improved, thus equalizing the circulation throughout the body. The blood-pressure is also favorably influenced, especially when increased Blood pressure is due to nervous or emotional grounds.
5. Deep Breathing Helps Singing: Singing requires deep breathing, as it builds stamina and thus improves capacity of Lungs and Abdomen which take active part while singing. Because of this and other reasons, deep Breathing is an excellent hygienic practice.
6. Deep Breathing Improves Mental Calmness & Capability: Breathing is also closely related to our mental condition. Agitation makes us catch our breath, and sadness makes us sigh. Conversely, slow and even breathing calms mental agitation. It is only because of this that, in the East, breathing exercises were used as a means of cultivating mental poise and as an aid to religious life.

Care during Deep Breathing: Muscular exercises results deep breathing, and, in general, the two should go together. But deep breathing if alone taken is also beneficial, if very slow. Forced rapid breathing is comparatively valueless, and indeed may be positively harmful because oxygen absorption in body depends upon its presence in the body and not according to the outside supply.