The Nasal Cycle and how alternate nostril breathing restores the Balance
A common man may not pay heed to the way air flows in the nostrils and might not notice that the flow of air in both nostrils is not equal at any point of time.
Most don’t realise, at a given time, only one nostril is predominantly active while the other is passive. The changeover to the other nostril becomes active after a period of about hour and a half or so and the first one goes passive. This alternating cycle of airflow predominance in one nostril is called the Nasal Cycle and this nasal cycle is a natural and a subconscious phenomenon.
During the time when this transition is happening, there is equal flow of air (call it Prana breath) from both the nostrils. The time period of the cycle is also affected by the surroundings, nature of tasks we do and the thoughts we entertain.
Role of the Erectile Tissue
While it is a fact that breathing happens in cyclical manner, a question is always asked what makes this cycle operational Nature has provided for this in the form of an erectile tissue which swells and contracts periodically to restrict or allow flow of energy through nostrils. This erectile tissue is similar to the one which is present in penis.
This tissue not only controls and regulates the flow of air in nostrils by altering the caliber of air passages, it also enables us to differentiate between the different smells. It also controls and regulates the amount of warming and humidification of inspired air.
The Nasal Cycle and the Ida-Pingala Connection
You would find it amazing to note that ancient scripture of ‘Shiva Svarodaya’ mentions that the flow of energy through the Ida and Pingala nadis is rarely equal and this is manifested in the air flow in and out of nostrils.
For the benefit of those who do not know about Nadis (or nerves), there are two nadis on either side of the spine, with the left one connecting spine to left nostril is called Ida and the right one connecting spine to right nostril is called Pingala. There is also a third one at the centre, called Sushumna which connects the spine to the base of both nostrils.
Ida, Pingala and the Right Brain-Left Brain Connection
Since there is domination of one nostril at a time during normal breathing, does it correspond to similar dominant activity in one hemisphere of the brain? It has been noticed that the left nostril is connected to activity in the right part of brain and the right nostril to the activity in left part of brain.
While breathing from the left nostril, the flow of air goes down Ida and the parasympathetic nervous system in the right side of brain gets activated. This brings feeling of relaxation and serenity. Similarly, while breathing through the right nostril, the energy goes down the Pingala and the left side of brain is dominantly activated. This activates the sympathetic nervous system which means that it helps in analytical or logical thinking. It also gives us more control to handle response to emergency situations.
What does the Alternative Nostril Breathing do this imbalance of air flow?
It has been observed that nasal cycle also depends on the nature of work being done. If the work pertains to analytical thinking or application of logic, then the left side of brain (sympathetic nervous system) gets activated more and the right nostril is dominantly active. However, it shall be remember that over activity of right nostril might also lead to decline in creativity which is associated with the right brain.
However, if the work is of creative nature, then the right side of brain and corresponding left nostril becomes dominantly active. If there is over-activity in left nostril, then there is a lack of concentration for doing the analytical tasks.
Now, the question is how does the alternate nostril breathing help in maintaining the equilibrium?
ANB ‘Alternate Nostril Breathing’ and the Equilibrium
When alternate nostril breathing is done, there is a conscious effort to inhale and exhale equally from both the nostrils. If any nostril is underactive or overactive, it works to improve or reduce the flow of air respectively. In this way, the balance is sought to be achieved by regulating the flow.
Once this balance is achieved and you begin to breathe equally from both nostrils, the Sushumna nadi is activated and there is flow of energy through it. Achieving the state of Sushumna gives a joyous and blissful experience.
Writer’s note: The article is just indicative. Please consult a wellness/yoga guru to know more on the topic…
 Chandra Bhedana Pranayama- Left Nostril Breathing.