I will say a few words on a very important matter that affects all our activities. This was originally taught by Shiva to Parvati.
As we breath in and out, we can notice that both nostrils are not equally open most of the time. For a while, left nostril is more open; for a while, right nostril is more open; and, for a while, both are equally open. It automatically changes in a cycle. An awareness of this cycle and planning our activities around this cycle can improve our lives.
Though modern science does not know the full importance of this cycle, it is now aware of this “nasal cycle” and that sympathetic and parasympathetic nervous systems controlled by the 2 halves of brain are more active when the corresponding nostril is more open!
The left half of brain is tied to the right nostril and the Pingala nadi or solar channel. It is linked to logic, deduction, ambition and the part of nervous system that provokes and “pushes” us to do things.
The right half of brain is tied to the left nostril and the Ida nadi or lunar channel. It is linked to emotion, intuition, contentment and the part of nervous system that “pulls-back” from exerting ourselves.
The balance between these push and pull-back nervous impulses is very crucial for a balanced life. If one pushes too much or pulls back too much, it causes imbalances and destroys one over time. So balance is crucial.
However, some activities benefit from a more dominant push impulse and some from a more dominant pull-back impulse. Accordingly, we can undertake activities that our nervous system is more conducive to at a given time.
For example, physical exercise, emptying bowels, arguments etc are better done when the right nostril is more open (i.e. push impulse). Undertaking these activities during the left nostril time will be unproductive or may even cause problems and diseases.
Similarly, enjoying nice music, going to sleep, reading a nice book etc are better done when the left nostril is more open (i.e. pull-back impulse). Attempting them during the right nostril time can cause problems.
Let me call the time when our right nostril (solar) is more open as the “internal day”. Let me call the time when our left nostril (lunar) is more open as the “internal night”. Let me call the time when both nostrils are equally open as the “internal sandhya” (sandhya=dawn/dusk).
When one is healthy, there are 8 internal days and 8 internal nights within an external day & night (i.e. 24 hours). One will have a sandhya for about 30 minutes, day for 1 hour, sandhya for about 30 minutes, night for 1 hour, again sandhya for about 30 minutes and so on. When one is not healthy and there is no balance between push and pull-back impulses, either day or night may be much longer.
If one closes the right nostril, breathes in & out from the left nostril, then closes the left nostril and breathes in & out from the right nostril, one can judge which nostril is more open. If one does it several times, one can get a sense of the cycle. With practice, one’s perception become subtle and it just becomes common sense. Being aware of one’s nasal cycle and having an idea approximately when the next change occurs is very useful for planning one’s activities.
What is the best time for meditation and other spiritual sadhana? Undoubtedly the “internal sandhya”!
When people say that sandhya is the most suitable time for sadhana, they normally talk about external sandhya. But that is less important than the internal sandhya. Irrespective of external time, when both nostrils are equally open is the BEST time to meditate.
By the way, certain activities such as intercourse and eating food should be avoided at all costs during internal sandhya. Those will cause serious problems.
Suppose one wants to sleep and the right nostril is more open. If one tries to sleep, one may have trouble falling asleep. Suppose one wants to exercise and the left nostril is more open. If one exercises, it may be unproductive or cause health problems. In real life, sometimes we may be forced to do a particular activity when the dominany nostril is unconducive. One can change/reset the nasal cycle in such cases, for it does come with a “reset” button. smile emoticon
If one puts pressure under the armpit corresponding to the currently dominant nostril, brain will automatically switch to the other nostril!
Suppose right nostril is more open and one wants to switch to the left nostril. One needs to apply pressure under the right armpit. There are 2 ways: (1) Lie down on the right side, thus putting pressure on right armpit. (2) Like rishis did, place a T-shaped wooden staff under the right armpit and apply pressure.
Either way, right nostril will close and left nostril will open, within 5-10 minutes. Then the cycle will continue from there, i.e. it will start to change within 1 hour and complete the change after 1.5 hours.
Due to imbalances in the nervous system, the cycle may not always be 1.5 hours of day and 1.5 hours of night (I am clubbing sandhyas with day & night here). Day or night may be longer in some cases. Please note that that is normal, though correcting it can improve one’s well-being.
However, if the same nostril is open for too long (e.g. 3-4 hours), it indicates a serious imbalance in the nervous system and an impending disease. Forcing a change of nostril (see above) can often avoid the disease, unless it has deep-seated root causes that cannot be suupressed anymore.
There is a lot more taught by Shiva to Parvati in “Shiva Swarodaya Shastra”. However, the above is the gist and includes most salient points. Most importantly, the teachings of sages and deities only provide a framework that intelligent persons can build upon. So understand this, contemplate further and experiment. Good luck!