In the neck there are two remarkable organs called the carotid sinuses situated on each side of the main artery supplying the brain with blood, in front of the neck and just below the level of the jaws. These small organs help to control and regulate blood flow and pressure. If there is any fall in blood pressure, it is detected by these two sinuses and the relevant message is sent directly to the brain centre. The brain responds immediately by increasing the heartbeat and contracting the arterioles (tiny blood vessels), thus raising the pressure to its normal level. Any rise in blood pressure is also detected by the carotid sinuses, which inform the brain and the opposite steps are taken to rectify the situation.
Tension and stress are associated with high blood pressure. Ujjayi pranayama by applying a slight pressure on these sinuses in the neck causes them to react as though they have detected high blood pressure, with the result that the heartbeat and the blood pressure are reduced below normal. One becomes physically and mentally relaxed. This is the reason why ujjayi is so important in many meditational practices. It induces overall relaxation, which is essential for success in meditation.
Khechari mudra accentuates this pressure in the throat region and consequently on the two carotid sinuses. The reader can experiment for himself by doing ujjayi firstly without khechari mudra and then with, and compare the difference in pressure.
Ujjayi pranayama is a simple practice but it has many subtle influences on the body and brain, both physical and mental as well as bioplasmic. The slow and deep breathing results in immediate calmness of the mind and body, as well as bringing the bioplasmic body into harmony. Furthermore, the sound at the throat tends to soothe one's whole being. If one remains aware of this sound for a reasonable period of time to the exclusion of other thoughts, then one will feel immediate benefits.