The role of breath in pranayama
Patanjali places pranayama after asana. Iyengar relates the sequence to the quality of support and the position of the body. Work with the breath draws on attention and preparation already developed through posture.
Observation and regulation
You can notice an inhale or an exhale while allowing its duration and depth to stay familiar. Pranayama, as described by Patanjali, involves deliberate work with breathing. The sutras distinguish forms involving inhalation, exhalation, and retention. Iyengar discusses where the breath is felt, how long it lasts, the precision of practice, and the steadiness of the torso.
Breath and attention
Sutra II.53 connects pranayama with preparing the mind for concentration. Iyengar examines how attention to the breath and the quality of effort relate to chitta. This helps explain why his discussion proceeds from pranayama to pratyahara and dharana.
A gentle starting point
Sit comfortably and notice your usual breathing for a short time. Let the pace and depth stay natural. If focusing on breathing becomes uncomfortable, stop. Deliberate breath holds and intensive techniques call for guidance from a qualified teacher, taking your health into account. Stop if you feel dizzy or markedly uncomfortable.
Why posture comes first
Iyengar discusses the position of the spine and torso in his account of pranayama. A person who has to keep shifting to stay seated is dividing attention between the breath and the work of remaining upright. In a supported position, it can be easier to notice what the torso is doing during an ordinary breath. This illustrates the sequence Patanjali describes. Asana gives a practitioner a way to examine support and effort before undertaking formal work with breathing.
What the text means by precision
Patanjali distinguishes aspects of breath practice by where they occur, how long they last, and how they are counted or measured. Iyengar uses those distinctions to discuss the quality of a practice. They describe what a trained practitioner pays attention to. A number in isolation tells little about the effort required, the way the torso is supported, or whether the practice is being done comfortably. The discussion is easier to understand when those observations stay connected.
From noticing a sensation to sustaining attention
Feeling movement in the torso is one part of observing a breath. Staying aware of the experience while thoughts or sounds come and go is another. The first concerns a sensation. The second brings the continuity of attention into view. That difference helps explain why Patanjali discusses the capacity for concentration after pranayama. It also gives a reader a way to understand the place of breath in the book without trying to reproduce the formal techniques from a description.
What to remember
Iyengar presents pranayama as a prepared practice involving posture, breath, and attention. Observing natural breathing offers a simple introduction to the subject. The techniques discussed in the book call for separate instruction.
Source
B. K. S. Iyengar. Heart of the Yoga Sutras.