In the normal, rhythmical breath exhalation takes about twice the time of inhalation. For instance, if inhalation require four seconds, exhalation, including a slight natural pause before the new inhalation, requires eight seconds.
The balancing of the electro-magnetic energies in the system depends to a large extent upon this rhythmical breathing, hence the importance of deep, unobstructed, rhythmic exhalation and inhalation.
In order to establish the natural rhythm of the breath when it has been impaired through catarrhal affections, wrong habits of breathing, or other causes, the following exercise, practiced not less than three times a day (preferably in the morning upon arising, at noon, and at night), will prove very beneficial in promoting normal breathing and creating the right balance between the positive and the negative electro-magnetic energies in the organism.
The Alternate Breath
Exhale thoroughly, then close the right nostril and inhale through the left. After a slight pause change the position of the fingers and expel the breath slowly through the right nostril. Now inhale through the right nostril and, reversing the pressure upon the nostrils, exhale through the left.
Repeat this exercise from five to ten times, always allowing twice as much time for exhalation as for inhalation. That is, count three, or four, or six for inhalation and six, eight, or twelve, respectively, for exhalation, according to your lung capacity. Let your breaths be as deep and long as possible, but avoid all strain.
This exercise should always be performed before an open window or, better yet, in the open air, and the body should not be constricted and hampered by tight or heavy clothing.
Alternate breathing may be practiced standing, sitting, or in the recumbent position. The spine should at all times be held straight and free, so that the flow of the electro-magnetic currents be not obstructed. If taken at night before going to sleep, the effect of this exercise will be to induce calm, restful sleep.
While practicing the "alternate breath," fix your attention and concentrate your power of will upon what you axe trying to accomplish. As you inhale through the right nostril, will the magnetic currents to flow along the right side of the spine, and as you inhale through the left nostril, consciously direct the currents to the left side.
There is more virtue in this exercise than one would expect, considering its simplicity. It has been in practice among the Yogi of India since time immemorial.