The data for study
We have studied the practice of snake breathing (the “ujjayi” after Swami Satyananda Saraswati) by method of ultrasound Doppler sonography using the Toshiba Nemio XG device.
The test person A. is a male aged 35 suffering from functional tachycardia.
According to the vegetative responsiveness tests (Ashner test, Gering test) the type of his responsiveness is sympathetic.
The study of vegetative maintenance (the orthostatic test) also shows excessive response of the pulse (during the period of body position change the pulse goes 35 to 40 points up) while systolic arterial and diastolic pressure change to a very little degree.
This type of responsiveness is traditionally referred to sympathetic type since it is sympathetic nervous system acting as a regulator of the cardiovascular system activity that is responsible for cardiac acceleration.
Sympathetic system is also responsible for vessels hypersthenia and heart force.
In the case under study the cardiovascular system responded to change of one’s body position by significant cardiac acceleration without due change of cardiac output and vessels tone.
It means there is misalignment in work of one’s heart and vessels caused by inadequate regulation of CVS work. In this situation the heart comes as the “weak link” — it takes little rest and is subjected to poor blood supply under the conditions of tachycardia.
Such response can be regarded as the state of functional disharmony, the pre-pathologic state.
After 5 minutes of the testee’s doing classical snake breathing the Test Person A. was observed to have:
HR (heart rate) reduction at 8 points;
Slightly increased stroke volume (SV) – at 3 ml;
The 7% increase of the ejection fraction (EF);
Slight reduction of endocardiac flows.
The increase of stroke volume and ejection fraction have their explanation:
The snake breathing actively engages the muscles of one’s pharynx that first of all facilitates complete incorporation into working process of the whole apparatus of respiratory muscles (Ujjayi in Yoga-therapy of Obstructive Sleep Apnea Syndrome (How Shall I Breathe if I Snore); second, as a result of such vagal response the skeletal muscles relax, including the respiratory muscles, and it also enables their better and more effective engagement into work (“Some Effects of Ujjayi, or Relaxation after Victory”).
In the course of practice such muscular respiratory activity is sensed as “the ability to open out one’s chest more actively”, “the ability to breathe in more air without hindrance and without additional efforts” (by the way, such sensation comes as one of inner criteria of successful snake breathing practice).
Active engagement of respiratory muscles results in better opening of one’s chest and thus to better heart filling with venous blood that automatically increases cardiac output (the Frank – Starling law of the heart).
The drop of arterial pressure and HR reduction is quite natural – this reaction comes as the consequence of two parasympathetic (vagal) responses. The first one we have already referred to (one’s pharynx is a reflex field); the second one occurs due to large portions of blood’ inflow to aorta where baroreceptors (the receptors of pressure) that regulate blood pressure in the whole organism are located. Because of their stimulation the cardiac rate drops.
In the condition of reduced HR parameters and increased SV and EF the endocardiac flows are naturally reduced.
The practice can be regarded as a stabilizing one under the conditions of initial sympathicotonia, functional tachycardia, since it stimulates parasympathetic element (its action is initially weak at the test persons’).
This practice can be also considered further as an element of the CVS training: it ensures sufficient load on the organ by means of blood volume yet does not invoke tachycardia.
(This type of breathing is particularly interesting in the practice of asanas – a physical exercise affects load on heart and muscles, the practice of breathing loads the heart and respiratory organs, i.e. the work of three systems – muscular, respiratory and cardiovascular – is synergized).
This practice requires more profound investigations in groups of persons with various kinds of pathologies.
The study of long-term results of this pranayama’ regular practice is also required.