The practice of breath control (pranayama) may be viewed in terms of its goals, the means to attain them, and possible misuses of the practice.
Goals of breath control include: to reduce the number of wandering thoughts; to stop wandering thoughts completely; potential production of a glimpse; lengthening of a glimpse, if obtained; and bringing about a glimpse if lost.
The most common means of achieving these goals through breath practices are dual, and include the holding of the breath for short, safe periods, and the equalizing of the in and out breaths.
Dangers of breath control, if improperly practised, include: holding the breath for too long a period, causing a feeling of suffocation; the arisal of noticeable pressure on the heart; and a feeling that the lungs are about to burst. These warnings do not imply waiting to suspend practice until the problem occurs. It is more prudent to stop before the danger line is reached.
-- Notebooks Category 5: The Body > Chapter 6 : Breathing Exercises > # 19
