Many people associate 'asanas' with gymnastic exercises or body building techniques. This is a totally wrong conception, for yogic asanas are neither designed specifically to allow a person to 'throws his body about' or to develop huge unnecessary muscles. They should be regarded as postures, poses or stages of being.
'Yoga' means the experience of oneness or unity with your Inner Being. 'Asana' means a state of being in which you can remain steady, calm, quiet and comfortable with your physical body and mind.
In the ancient text on yoga by Patanjali called the 'Yoga Sutras' there is a very concise definition of yogasanas: 'Sthiram sukham asanam' which means the position, which is most comfortable and steady.
So we can see that yogasanas in this context are practised to develop the person's ability to sit in one position without discomfort for extended lengths of time, as during meditation.
Asanas can also be performed for curative and health reasons. Gently stretching the muscles, massaging the internal organs and toning the nerves throughout the body can improve the health of the practitioner improved tremendously.
There has been specific research, which has proved yoga to be among the most effective cures for many ailments. It helps to manage and control stress related problems such as anxiety, fatigue, depression, heart disease, blood pressure. It is acknowledged to be among the most effective treatments for chronic back pain, arthritis, bone density problems, constipation and PMS
Yoga also helps your body by -
Boosting your self-esteem and confidence