This is how it works. The right nostril dominance is associated with pingala nadi or surya nadi (nadi is the channel through which pranic energy flows in the body; we are said to have 72,000 nadis but there are three principal ones, of which pingala is one. Another is ida and these two are said to flow along the length of the spinal cord, on either side of the main nadi or the shusumna). The pingala, which is the masculine or solar principle, is associated with the left hemisphere of the brain that controls the right side of the body.
The left nostril dominance is associated with the Ida nadi or chandra nadi, the feminine or lunar principle, associated with the right hemisphere of the brain and controlling the left side of the body. Just by observing the direct effect of solar and lunar currents of breath on human behavior, swara yogis were able to ascertain the activities best suited during the left nostril dominance and activities best suited during the right nostril dominance. The nose can be seen as the main switch of cerebral hemispheres. It can stimulate electromagnetic activity on one side of the body and it can switch the hemispheric activity on and off at will.
