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Dirgha= big, nauka= boat. i.e. streaching and upward bending of limbs making shape of the body like boat

Method:
1.    Lie down in Shavasan and straighten both the hands while taking them to the back of the head together.
2.    Inhale, slowly raise the legs, head and hands at least one foot above the ground level keeping the hips and the lower portion of the back touching the ground. Keep looking at the chest. While coming down, exhale and slowly rest the hands, legs and head on the floor.



Benefits:
1.    It is beneficial for the stomach and back just like Naukasan.
2.    It is the best aasan to strengthen the heart. It is thus also called Hridaya-sthabhaasan.