Katopanishad describes prana as the upward movement of the breath and Apana as its downward movement "urdham prana munna yathyapanam prathy a gasathy." Many do pranayam by alternate closing of one of the nostrils with the finger and retaining the breath as long as possible. This is not the correct method, as no neutralisation is effected in this practice. The writer has been warned against this practice by his Guru Swami Sivananda Parama Hamsa, the founder of Siddha Samaj who is now in Nirvikalpa Samadhi. He has also pointed out to the writer the common mistakes that people make in the practice of yoga, which is beyond caste, colour, creed or sex and the wrong notions they have imbibed regarding certain vital terms and expressions used in the yoga literature. The writer is only a student of yoga. But he feels constrained that he should, with humility, share the knowledge he has gained with readers for their benefit.

The initial mistake that is often made, is with regard to the understanding of the three Kalas or Nadies, viz., Ida, Pingala and Sushumna. Yoga being a prevedic cult one has to trace the prevedic origin of the terms usually employed in the yoga literature, from their Dravidian or proto Dravidian sources. Kala is the Shakthi or energy inherent in jeeva the life principle. It is the creative force from which impulses of creation start in the form of monadic Bindu which vibrates as Nada. From Nada the phenomenal world evolves. Kala is called Nadi (that which is moving) because of the flow of Nada. As Nada is the immediate cause of the phenomenal world it is called Nada Brahman, and Shakthi, its original source is called Nada Rupa (form of sound).

Ida Nadi is wrongly understood as the flow of air through the left nostril starting from the anus region and Pingala as the flow of air through the right nostril, also starting from the anus region. Sushumna is considered to be some current or energy also starting for the anus region and plying in between Ida Nadi and Pingala Nadi. It is because of this wrong notion that the practice of pranayam is wrongly done by many by closing the right and left nostrils alternately and performing the breathing process, retaining the breath inside the lungs by force, as long as possible.