The word “shuddhi” or “shuddha” can mean “purifying,” “clearing,” or “cleansing.” Typically, the channel cleansing or clearing is performed by applying the Nadi Shodhana Pranayama breathing exercise. This latter Yogic exercise is more popularly known as the Alternate Nostril Breathing technique.
Nadi Shodhana then would mean something like “Cleansing the Energy Channels.” It’s thought to notably refer to clearing, opening, or unblocking the three principle Yoga Nadis — Sushumna Nadi, Ida Nadi, and Pingala Nadi.
A bit contradictory though is the idea that Nadi Shuddhi — cleansing of the energy channels — needs to be done with a Pranayama (with Nadi Shodhana) before practicing Pranayamas. In fact, it makes Nadi Shodhana a kind of meta-Pranayama.
In any case, the health benefits attributed to practicing Nadi Shodhana are manifold. Think, for instance, of reduction of anxiety and stress, stimulation of better sleep patterns, heart rate control, expulsion of toxins and waste products out of the body, relaxation of the nervous system, improvement of cardiovascular function, cleanse of the respiratory system and Life Energy Channels, mental clarity, improved concentration ability, and promotion of general well-being.