The process of "pranayama", which should be learned from an experienced teacher, utilizes this principle to prepare the mind for more advanced stages of sadhana (intuitional practice). There are different types of pranayama, for different purposes.
Besides, the breathing also affects the heart rate, through the so called "RSI" - Respiratory Sinus Arrhythmia - response. This is an effect well known in medical science. From the term we can learn that it is a para-sympathetic action, controlled via the left and right Vagus nerves. These are some of the major cranial nerves, belonging to the ANS (Autonomous Nervous System) directly running from the brain stem to the heart's SA (sino-atrial) resp. AV (atrio-ventricular) nodes. This way, the part of the brain concerned with basic vital functions very subtly regulates certain aspects of the heart rate, related to the breathing cycle and to other primary functions. Through the "SNS" (Sympathetic Nervous System) effect on the other hand, the heart rate is accelerated, which becomes very obvious in the fight- or flight response. Thus we can profoundly learn from the heart, or more precisely, the heart rate, as is at the centre of a complex adjustment of various vital functions, reflecting certain essential psychic states associated with it. As a modern science this is called "psycho-physiology". It is, in a somewhat limited sense, similar to the concept of "bio-psychology" used by Shrii. P.R. Sarkar.
A special type of breathing, or rather breathing rhythm, is the so-called "baro-reflex rhythm". It was found that a certain breathing rhythm synchronizes with the natural aortal pressure circuit, which is optimal especially for relaxation and stress-release. The typical baro-reflex rhythm lies around 6 cycles / minute, or 10 seconds / cycle.
Now, with regard to the so called "Four Chambers of the Universe" (microvita cosmology), Sarkar explains: "(A) Subjective controls and relates to (B) Objective, and (B) Subjective controls and relates to (A) Objective". Here, the (A) and (B) subjective are both "Purusa's", or Purusa aspects. As the single Purusa cannot literally be it's own witness, it must create various objective faculties in order to express itself. This process is called "bifurcation". The primary objectivities are propensities and inferences (pure vibration), and trigger the evolution of microcosms. The subjective control or attraction (of the objective factors) is not exactly equal to, but helps in the process of evolution.
Therefore, when a baby is born and it starts taking it's first breaths, also it's heart rate starts fluctuating, and it's mind is starting to function. This we can say is how the macrocosm bifurcates itself and out of itself it creates a human being, a living soul. Evolution has ever so slowly built up the crude and subtle sensory faculties needed for practical life, and although this by itself does not exactly constitute a body of karma, it is the repository of it. Without "karma" (imperfect adjustment), bifurcation would still remain a bit theoretical, and there would be no sense of personal existence. The process of pranayama then, helps to calm the mind and nervous system and thus, so to speak, reunite Heaven and Earth.
Our breathing cycle crosses the Four Chambers of the Universe in various ways, with various types of impact. As a sequential flow, it relates to our mental propensities and thought vibrations in ways we are quite familiar with. Typically, if the breathing is calm, our mind is also calm. This we may say is the normal breathing wave. To increase the calming and transcending effect, the cycle can be paused, usually after inhalation, and this of course evolves various forms of pranayama.
Now, similar to the internalized state in philosophy, in the Four Chamber Universe we recognize not only a sequential cycle (in continuous time and space), but also a simultaneous cycle or state. The relation between the sequential and simultaneous phases is very subtle. It is referred to by Shrii P.R. Sarkar as a state of "plus or minus equilibrium". It can accurately be described with sub-wave theory, but it can only be fully appreciated in an intuitional, and verily mystical approach.
In order to deepen our understanding, and ever increase our proximity to that mystery, we may at one point need to transform our continuous breathing wave into a special kind of breathing, a special flow "plus or minus equilibrium". As this state is neither chaotic as in normal life, nor controlled like in the case of pranayama, there must be a third way, and that is, to surrender our breathing to the greater flow of creation and merge with it. Only by way of preparation, we can do some effort ourselves.
Naturally, there is a certain imbalance between our inhalation and exhalation, and this breathing ratio reflects the mathematical ratio between the simultanous and continuous creation cycles of the Four Chamber Universe (known in sub-wave theory). The inhale is quicker, and therefore noisier, and this noise is reminiscent of the (B) Objective Chamber, that is, vibration. After inhalation, we arrive at the externally silent, expanded state of (A) Subjective. But we do not stay there, because that would prohibit the "plus or minus equilibrium". The exhale is slower, and therefore more silent. The energy released forms the (A) Objective Chamber, that is, propensities, but we move on to the internally quiescent and blissful, unmanifest state of (B) Subjective. Also, we don't stay there, and proceed again to the next external cycle.
The deeply intuitional realisation is the true meaning of "plus or minus equilibrium", or in other words, equilibrium may create non-equilibrium, but together they still remain in equilibirium. This cannot be appreciated through intellectual analysis alone, only through real experience. If this is achieved through our effort to do a special kind of breathing, at one point we may begin to experience that our entire system - lungs, heart, circulation, nervous system, and mental and emotional states all move as one. We will feel as if it is the Macrocosm itself who is breathing, or, as the spiritual devotee says, "it is the Almighty breathing through me".