Asana is the third limb of Ashtanga yoga. It means posture. A steady and pleasant posture produces mental equibrium and prevents fickleness of mind.
The body is controlled by the nervous system, the nervous system is contreolled by mind and the mind is influenced by the senses and sense objects. The mind reacts and respond to the sensations which the body experiences through the sense organs and brings about different states of emotions such as anger, hatred, passion, depression etc.,
The mental state in which one remains influences the nervous system and the nervous sytem in its turn acts upon the body. Diseases are caused by the malfunctions are defects of glands or internal organs, which are all controlled by the nervous system.
Now, yogasanas have a gentle massaging effect upon the nerves, internal organs and glands. Through the practice of asanas the glandular function can be brought in order again. By the practice of yogasanas one can learn how to control these functions and how to maintain order in the body.
By the practice of asanas regularly, stiffened limbs and unexercised muscles are made loose and supple again. For ex; Headache is no more than a contractions of certain nerves in the head. By the practice of the asanas the nerves are relaxed thus eliminating the pain.
Everyone agree that a healthy body is the most basic need of each man. A healthy body is the first step to an optimistic, creative and healthy state of mind.