There are three fundamental nadis or energy channels in the human system according to yogic philosophy, the Idâ, Pingalâ and Sushumna. The 72,000 nadis in the body spring from these three basic nadis – the left, the right and the central – the Idâ, Pingalâ, and Sushumna.
The word “nadi” shouldn't be confused with nerves. Nadis are pathways or channels of Prāṇa. Prāṇa means vitality, aliveness. Prāṇa is the subtle life force/breathe. The 72,000 nadis in the human system don’t however have a physical manifestation. This means if you cut the body and look inside, you will not find them. They are in the Prāṇamaya kośa, the vital sheath in the subtle body. As you become more aware, you will start to feel their impact.
The System of nadi's is not superficial. This system is deep towards to the core of our being. This system that comprises the nadi's is the most beautiful part of us according to the yogi's. This is our Being. This is beauty, grace, strength and "adamantine hardness" but at the same time it has the softness of a lotus flower. This core of our being is strong yet fragile. Masculine yet feminine. It is as if a lotus flower that is made of diamonds. Or a diamond that is made from a lotus flower. All opposite meet at the core of our being.
The Hatha Yoga Pradīpikā says that hatha yoga is the union of the two energy forces in the core of your body, the energy flowing in Idâ and Pingalâ nadis. Usually, these two forces do not operate simultaneously; either the mental force predominates or the vital energy is dominant. This creates an imbalance within the human system. Hatha yoga is the process of balancing the flow of these two alternating forces to bring perfect physical and mental equilibrium and awakening of sushumna and kundalini. Yoga aims to unite these two energies and channelise them through the third nadi, sushumna. When this happens, there is an awakening for the yogi.<