Nadis are subtle channels through which the Prana / life force energy flows from one chakra to another and circulates to the whole area of the physical body and subtle body. The nadis forming a whirling energy network in the aura intercommunicate with the physical body via the chakras.
When nadis get congested with stagnant energy it will create disorder in the physical body in the form of pain, disease etc so it is very important that nadis should be free of blocks in order that prana can flow freely all over the body.
Nadi network in physical and subtle body According to ancient Indian texts there are around 72,000 nadis in the body out of which three are the principal nadis.
Greek symbol showing Ida-Pingala - Sushumna Nadis
Ida and Pingala are situated on each side of the spinal column, Ida on the left and Pingala on the right. The Sushumna nadi is centrally located and travels along the spinal canal. The ida and pingala nadis also travel upwards along the spinal column, but they crisscross each other and the sushumna on their way as per Traditional Indian Medicine and several other philosophies. (coiled serpent approach) whereas traditional Buddhist philosophy shows that Sushumna flows along the spinal cord and the pingala and ida flow relatively in straight lines parallel to sushumna on either side.
Nadis can be compared to the meridians used in Chinese acupuncture which are pathways for the flow of Qi / prana.
Pingala , Ida & Sushumna on the front side of body
Pingala and Ida Nadis correspond roughly to the two parts of the Autonomic Nervous System - Sympathetic and Parasympathetic respectively. The autonomic nervous system (ANS) regulates the functions of our internal organs such as the heart, stomach and intestines. The ANS also controls some of the muscles within the body and glands. Hence cleaning nadis would activate the autonomic nervous system thus enhancing overall health.