Nadis are channels that carry prana through the body. Depending on which lineage you examine, there are between three and hundreds of thousands of nadis in the human body. This vague description is frustrating from a scientific approach because there is no tangible way to represent the nadis.
Nadis, like all aspects of yoga anatomy, prove to be esoteric in nature, but are nonetheless worth discussing as part of a holistic way of understanding yoga philosophy. Just because something isn’t tangible doesn’t mean that it doesn’t exist. The mind itself is intangible, but we still know and understand that we possess knowledge and memories within the mind.
For our purposes, we will briefly examine three nadis:
Pingala, ida and sushumna.
Pingala (heat, solar) is on the right side of the spine. Ida (cool, lunar) is on the left side of the spine. Sushumna (gracious, balanced) runs along the center of the spinal cord. If the tangible part of the body such as nerves, arteries, capillaries distribute nutrients, blood and fluids throughout the body, imagine that the imaginary nadis carry mental, intellectual and vital energy. The nadis weave their way through all the chakras.
Pingala nadi is associated with extroverted energy, logical linear thinking and efficiency.
Ida nadi is associated with introverted energy, creative thinking and patient decision-making.
Sushumna nadi is the central channel through the body. It represents a balance between high and low energy. When your energy is in your sushumna nadi, you are in good physical and emotional health. When prana is not in sushumna, it is due to something blocking energy. An impurity has been brought into the body through negative thinking or unhealthy action.
Asana and pranayama practice, as well as observance of the yamas and niyamas are the tools to keep energy in sushumna nadi and maintain balanced health.