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Yoga & Health

Expert - View Pranayama (breathing exercises) in Light of Contemporary Science

Dejan Kupnik, M.D.
Centre for Emergency Medicine - Prehospital Unit, Maribor/Slovenia

(certified YIDL teacher)

The common story about our need for oxygen to enable normal functioning of the body cells, has expanded with many new chapters in recent years. These new "chapters" have enriched our knowledge about psycho-physiological processes and a rather intriguing proposition can be concluded from some of them – namely, that there is likely to be something more than oxygen needed for sustaining our physical body. The Science of Yoga speaks of "prana", which is defined as the life force governing all of the body's physiological functions. Could it be that beyond the realms of our knowledge there is something more, connecting us to the very truth of our existence? Slowly the modern Western and ancient Yogic sciences seem to meet in mutual discoveries. Many of these discoveries were made some thousands of years ago and are being rediscovered in the present time.

What does Yoga teach about subtle body energies?
The forefathers of the ancient science of Yoga realised that the meaning of our existence can only be found within us. The ultimate truth can not be revealed through external science, because the more a man is aware of his true nature the more he sees that on the outside something is always wrong or missing, no matter what we do. These yogis of old realised that our body represents the ultimate and most sophisticated instrument. By balancing physical, mental and spiritual planes of existence we become better able to answer the fundamental questions: who am I, where did I come from, where am I going, what is the purpose of my life? No matter what form of life we consider, there is always an abundance of energy flowing through it. The same goes for the human being. According to yogic science there are thousands of energy channels flowing through the body and these are called nadis.

Picture 1 - Chart of nadis

Nadis should not be equated with nerves; rather, they are the channels through which the primordial energy or prana flows as it governs the functioning of the mental and physical planes of our existence. Areas where the energy becomes most concentrated are called energy centres or chakras. They are related to or connected with particular parts of the body, most notably with some glands. We know that glands work together with the nervous system to coordinate and influence all psycho-physiological functions of the body. Wherever energy becomes blocked or cannot flow efficiently for some reason, the normal functioning of different body parts becomes disrupted and if it lasts for a longer time, diseases can emerge. The ancient yogis discovered that by practising asanas and pranayama we can efficiently remove pranic energy blocks, thereby allowing our body to regenerate more efficiently. These blocks are removed by a process of harmonisation, or restoring of balance, and it is this balancing principle that yoga and its science represent. The ancient sages also discovered that among the thousands of nadis there are three which are the most powerful energy channels and, when purified enough, these can promote the development of the human being in all three planes: physical, mental and spiritual, allowing us to reach higher levels of consciousness. These channels are called IDA, PINGALA and SHUSHUMNA.

Picture 2 - Chakras and 3 main nadis

Pranayama techniques act to purify the nadis including these three main energy channels. Yogis discovered a long time ago that breathing through the left nostril stimulates the IDA nadi or the “moon channel” (connected with the parasympathetic nervous system) and breathing through the right nostril stimulates the PINGALA nadi or the “sun channel” (connected with sympathetic nervous system). By balancing the functioning of both nadis (that is, both aspects of the autonomic nervous system) we can stimulate the main energy channel called SHUSHUMNA and harmonize the activity of the nervous system as a whole. This was a great discovery, which has been proven by modern science and we will discuss it further in later chapters of this article. With such stimulation and purification we can more easily become aware of the obstacles, which are hidden deeply in our subconscious and, even at the unconscious level, we can overcome many mental and physical obstacles and finally make progress on the spiritual plane. But merely the techniques that yoga offers aren't enough. We have to develop universal love and have to rid ourselves of hatred, jealousy, greed, passion, anger and hypocrisy. We have to understand that every creature loves its life and doesn't want to die. We have to be protectors and not destroyers. We have to live creatively.

Correct breathing is the basis of all the Pranayama techniques

Most people do not breathe in the right way. So it is our first task, before starting any breathing exercises, to learn how to breathe correctly. Any exaggeration or performance of advanced levels of pranayama when the body has not been prepared, can cause breathing difficulties and uncomfortable symptoms and signs, such as nervousness, shortness of breath, unstable blood pressure, "nervous heart" (tachycardia) and many more. Breathing exercises have to be understood as a tender flower, that needs our daily care and sustenance. Only in this way can gradual and natural development take place, bringing the right results. Any tension or discomfort during breathing exercises is a sign that the body is not yet prepared and that we have to improve the performance of basic breathing exercises before we continue. We have to train and adapt our breathing organs and centres and all other breathing functions, to these new patterns of breathing in a smooth, gradual, natural and non-forceful way.

The basis of all breathing techniques is the complete or full breath when, during inhalation our belly expands first, followed by the chest, and during exhalation our chest then belly relax passively. This way we are able to use our main breathing muscle, the diaphragm, to full effect, inhaling larger quantities of air. From these extended movements of the diaphragm, abdominal organs are massaged, and blood circulation and digestion processes are improved. During inhalation the pressure in the abdominal cavity increases, quickening the flow of blood towards the heart and lungs, thereby strengthening these vital organs.

Throughout our lives we not only forget how to breathe in the correct manner, but also the ratio between the inhalation and exhalation changes and becomes erratic. It is important to know that when we breathe optimally and in a relaxed way, there is a natural ratio of 1:2 between the length of inhalation and exhalation. This means that the exhalation is twice as long as inhalation – if we inhale for 4 seconds the exhalation should normally last about 8 seconds, but again we should not feel any discomfort. This is achieved through regular daily practice, ideally from the time of our first introduction to breathing exercises. However, we should by no means force ourselves to achieve the mentioned 1:2 ratio in order to progress more rapidly, because sooner or later the body will react negatively to such a forced way of breathing. We have to come to it gradually, because only then will the body adapt naturally, avoiding any later problems. By performing breathing exercises in a reclining position we can improve the awareness of our breathing and learn more effectively the right way to breathe. A few weeks are enough for the body to adapt to the new breathing patterns and we soon experience the body breathing in the correct way, without needing to influence it deliberately. Our conscious effort establishes new, improved and complete subconscious breathing activities and these can be considered the foundations of evolution itself. Throughout evolution many battles are fought on the fields of survival and only the best and most adaptable organisms survive. Every new function that assists survival is incorporated in the organism. In other words, they originate in the initial plane of the conscious struggle, but then pass gradually into the subconscious, allowing progress to continue in other fields of life without being concerned with firmly established physiological functions.

When we are in an upright position there is much better blood flow through the lower parts of the lungs (1), but if we perform breathing exercises in the recumbent position, hydrostatic pressures equalize throughout the lungs and this improves the blood flow in all lung regions, thus allowing the body to take up more oxygen during inhalation. So these type of breathing exercises (performed lying on the floor), which are also the basic breathing exercises in the Yoga in Daily Life® system (2), are highly recommended immediately after practising individual asanas (physical yoga exercises or postures) because they increase the supply of oxygen to the body and enable the body to cope better with the temporary lack of oxygen experienced during the asana. They also allow us to exhale larger quantities of carbon dioxide produced during exercising.

Only when the new patterns of breathing are established can we proceed with further techniques of pranayama, and here again the rule applies that we progress gradually from the easiest towards more advanced techniques. One must not forget that the body needs time to adapt and that we should be free of all tension or discomfort during the exercise. Practising pranayama lowers respiratory rate, increases vital capacity, improves exhalation and increases the ability to hold the breath for longer periods (30).

There are health limitations to the practising of some pranayama techniques (see the first article about pranayama), but nadi sodhan pranayama, the pranayama technique most often studied, can be practised more or less by everyone.

Brain activity influences the pattern of our breathing

We know that there exists the so called nasal cycle which is influenced by our central nervous system and that it contains a period when we can breathe more easily through the left nostril and another analogous period for the right nostril. This is connected with changes in cerebral hemispheric dominance which was proved with EEG recordings showing that higher activity of the right brain hemisphere results in easier breathing through the left nostril and the higher activity of the left brain hemisphere results in easier breathing through the right nostril and that this cycle changes every 25 to 200 minutes (3). So when we breathe more easily through the left nostril, the functioning of the right brain hemisphere is more pronounced and dominant than the left. Easier breathing through the right nostril, on the other hand, means that the left brain hemisphere is currently dominating. When we can breathe equally through both nostrils there is some kind of balance between left and right brain hemisphere functions and throughout the nervous system. Interestingly this happens mainly in the time of dawn, midday and sunset when the vital energies of nature are at their strongest.

Can we influence the brain activity by practising pranayama?

But what is even more interesting is that, besides this influence of the brain on our breathing process, the influencing also works the other way around – in other words, we can use our breathing to influence the brain. By practising the alternating breathing through the left and right nostrils we can naturally balance the functioning of both brain hemispheres (11). Careful observation of our body and breathing can show us which part of our nervous system is more dominant in a given moment and enable us to act in accordance with it. By that we can, through conscious effort, influence the functions of different brain centres. We can also increase the perception of mental and physical energy and awaken feelings of alertness and enthusiasm, thus creating a positive mood (7). These discoveries are the results of many studies dealing with the selective stimulation of brain hemispheres through alternate nostril breathing (4)(5)(6)(7)(8)(9)(10).

Breathing through the left nostril stimulates the right brain hemisphere and intensifies the functions of the parasympathetic nervous system. This is connected with a slowing-down of the heart rate and consequently greater stroke volume of the heart (greater amount of blood is pressed out of the heart per beat, as a consequence of lower heart rate) (12).

Breathing through the right nostril stimulates the left brain hemisphere and the sympathetic nervous system. This results in accelerated heart rate, higher blood pressure, greater consumption of oxygen by the body cells and constriction of the blood vessels of the skin (13), thus preserving body temperature (which explains how some yogis can be totally oblivious to extreme weather conditions).

One study reports changes in the concentration of blood plasma catecholamines and their correlation with the nasal cycle (14). Catecholamines are hormones, which regulate many body functions and are secreted upon stimulation of the sympathetic nervous impulses. This happens in conditions of mental and physical stress (pain, cold, heat, oxygen deficiency, fear, anger). Catecholamines trigger the release of glucose and fats (as energy sources) that are stored within the body. They also cause constriction of the blood vessels and increased blood pressure, heart rate and strength of heart contractions. Additionally, they dilate the bronchi, increase the basal metabolism of the body and mental activity and promote the body's capability to coagulate blood. There are many more effects of sympathetic stimulation but let it suffice to mention the above most important ones. It has been frequently observed that people who suffer from some anatomical changes in the nose (deviated nasal septum, etc.) and breathe mainly through the right nostril, stimulate the sympathetic nervous system and consequently they have problems with high blood pressure. A simple remedy for this is a small operation of the nasal septum after which they can breath equally through the both nostrils and the levels of blood pressure soon normalise.

Alternate nostril breathing (as in nadi sodhan pranayama) balances the functioning of the left and right brain hemispheres (11), improves spatial orientation and spatial memory (left nostril), improves verbal expression (right nostril) and cognition (4)(6)(8)(15). The latter enables us to gain knowledge about the world around us, to analytically define it, to formulate memories and, based on our experiences, to plan and act accordingly. Among mentally handicapped children, a considerable improvement of cognitive functioning and social adaptation was achieved by practising pranayama, asanas and short meditations, for five hours a week. The improvement was clearly more pronounced in this group of children than in the control group in which children did not practise any yogic techniques (16). We mentioned that with the help of alternate nostril breathing it is possible to also influence the heartbeat. When we lower the frequency of the heartbeat (by practising exercises such as nadi sodhan pranayama) we allow our heart to rest a little bit longer than usual between two consecutive contractions. This additional resting allows the heart to be filled with larger quantities of blood and to contract with greater strength, thereby strengthening the heart muscle and maintaining it in better condition.

Other effects of pranayama

Today we know that substances called free radicals are closely linked with the development of many chronic degenerative diseases such as cancer, aterosclerosis (hardening of the arteries which can cause heart attacks and strokes), joint inflammations and others (17). Certain substances called antioxidants can act effectively against these dangerous free radicals and neutralise them. We can ingest large amounts of these protective substances through food (selenium, vitamins A, C and E, etc.), but our body is also capable of producing the antioxidants itself. There is positive evidence that pranayama can significantly lower the amount of dangerous free radicals along with a modest increase of the body's intrinsic quantities of antioxidants (18). This could be an as yet unknown mechanism to successfully neutralise free radicals – practising pranayama regularly can help us to fight against the diseases mentioned above.

Practising pranayama also improves the lungs' vital capacity (23). In some studies of people suffering from asthma it was discovered that pranayama caused general health improvement through the enhancement of lung function. There were reports of improvement of the vital capacity and "forced expiratory volume in the first second" (FEV 1 - a measure of forced exhaled air in the first second giving the information about how much the airways are constricted and not allowing the air to be exhaled). Regular practice of pranayama by asthmatics (but not during asthmatic attacks!) was shown to reduce the number of attacks and improve respiratory capacity during physical exercise. Other reports showed successful reduction of the usual daily dose of anti-asthmatic drugs (19)(20)(25)(26). One of the studies reported that the reactivity of the bronchial tree was significantly lowered after practising pranayama and that significantly more histamine was needed to lower the FEV 1 by 20% in the bronchial reactivity tests (27). Good results were also obtained in patients with chronic bronchitis, lowering the intensity of dyspnoeic (short breath) difficulties and improving the lung function in general (28). From that we can assume and conclude that pranayama has protective and relaxing effects on the whole respiratory tract (29). Of course, pranayama shouldn't be considered a cure for asthma and bronchitis, but with regular practising it can improve the health condition considerably. There were also some observations that pranayama speeds up rehabilitation following the punction of pleural effusions (21). Breathing through the left nostril is connected with higher intraocular pressure and breathing through the right nostril lowers that pressure (22).

What about pranayama exercises that involve holding the breath?

When we begin with pranayama practices we shouldn't try to hold our breath, but should instead breathe naturally and smoothly. Only after considerable time, when we have mastered the basic breathing exercises and we have no contraindications against it (see the first article about pranayama) can we proceed with advanced pranayama, which include holding of the breath (kumbhaka). Some very interesting discoveries have been made about such types of pranayama. Namely, it was discovered that by holding the breath during pranayama (i.e., by doing kumbhaka) metabolic processes in the body decrease in intensity and the body's consumption of oxygen is reduced to some extent (24). This means that with this kind of pranayama our body slows the metabolism and uses the energy conserved in some other way. This inevitably makes us wonder if there is something else that sustains our body, despite such low consumption of oxygen and reduced metabolic activities. With this kind of pranayama we also influence the parasympathetic nervous system, lowering heart rate and blood pressure (31).

Beyond the realms of current knowledge

Is there something beyond our current understanding of the body's psycho-physiological functions? It seems that the science of yoga offers so much, yet it is up to us to take advantage of this opportunity. From all the ancient and current knowledge we can say that breathing is not given to us for mere survival. Through various breathing exercises performed correctly we can explore and unveil in completeness, the possibilities that our body offers. We can influence the functioning of the brain, conserve body energy, adapt to various external difficulties such as cold and heat, and efficiently regulate our metabolism according to current needs. And, most importantly, we can proceed with our quest for answers to the ancient questions of who we really are, and what is our true nature.


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1. Guyton AC, Hall JE. Medical Physiology, 10th ed. Philadelphia: W.B. Saunders company; 2000.

2. Paramhans Swami Maheshwarananda. Yoga in Daily Life - The System. Vienna: Ibera Verlag/ European University Press; 2000.

3. Werntz DA, Bickford RG, Bloom FE, Shannahoff-Khalsa DS. Alternating cerebral hemispheric activity and the lateralisation of autonomic nervous function. Hum Neurobiol 1983; 2(1): 39-43.

4. Velikonja D, Weiss DS, Corning WC. The relationship of cortical activation to alternating autonomic activity. Electroencephalogr Clin Neurophysiol 1993 Jul; 87(1): 38-45.

5. Werntz DA, Bickford RG, Shannahoff-Khalsa DS. Selective hemispheric stimulation by unilateral forced nostril breathing. Hum Neurobiol 1987; 6(3): 165-71.

6. Shannahoff-Khalsa DS, Boyle MR, Buebel ME. The effects of unilateral forced nostril breathing on cognition. Int J Neurosci 1991 Apr; 57(3-4): 239-49.

7. Wood C. Mood change and perceptions of vitality: a comparison of the effects of relaxation, visualisation and yoga. J R Soc Med 1993 May; 86(5): 254-8.

8. Jella SA, Shannahoff-Khalsa DS. The effects of unilateral nostril breathing on cognitive performance. Int J Neurosci 1993 Nov; 73(1-2): 61-8.

9. Telles S, Nagarathna R, Nagendra HR. Breathing through a particular nostril can alter metabolism and autonomic activities. Indian J Physiol Pharmacol (India) 1994 Apr; 38(2): 133-7.

10. Dane S, Caliskan E, Karasen M, Oztasan N. Effects of unilateral nostril breathing on blood pressure and heart rate in right-handed healthy subjects. Int J Neurosci 2002 Jan; 112(1): 97-102.

11. Stancak A jr, Kuna M. EEG changes during forced alternate nostril breathing. Int J Psychophysiol 1994 Oct; 18(1): 75-9.

12. Shannahoff-Khalsa DS, Kennedy B. The effects of unilateral forced nostril breathing on the heart. Int J Neurosci 1993 Nov; 73(1-2): 47-60.

13. Telles S, Nagarathna R, Nagendra HR. Physiological measures of right nostril breathing. J Altern Complement Med 1996 Winter; 2(4): 479-84.

14. Kennedy B, Ziegler MG, Shannahoff-Khalsa DS. Alternating lateralisation of plasma catecholamines and nasal patency in humans. Life Sci 1986 Mar 31; 38(13): 1203-14.

15. Naveen KV, Nagarathna R, Nagendra HR, Telles S. Yoga breathing through a particular nostril increases spatial memory scores without lateralised effect. Psychol Rep 1997 Oct 8; 81(2): 555-61.

16. Uma K, Nagendra HR, Nagarathna R, Vaidehi S, Seethalakshmi R. The integrated approach of yoga: a therapeutic tool for mentally retarded children: a one-year controlled study. J Ment Defic Res 1989 Oct; 33(Pt 5): 415-21.

17. Lesgards JF, Durand P, Lassarre M, Stocker P, Lesgards G, Lanteaume A, Prost M, Lehucher-Michel MP. Assesment of lifestyle effects on the overall antioxidant capacity of healthy subjects. Environ Health Perspect 2002 May; 110(5): 479-86.

18. Bhattacharya S, Pandey US, Verma NS. Improvement in oxidative status with yogic breathing in young healthy males. Indian J Physiol Pharmacol 2002 Jul; 46(3): 349-54.

19. Nagarathna R, Nagendra HR. Yoga for bronchial asthma: a controlled study. Br Med J (Clin Res Ed) 1985 Oct 19; 291(6502): 1077-9.

20. Vedanthan PK, Kesavalu LN, Murthy KC, Duvall K, Hall MJ, Baker S, Nagarathna S. Clinical study of yoga techniques in university students with asthma: a controlled study. Allergy Asthma Proc 1998 Jan-Feb; 19(1): 3-9.

21. Prakasamma M, Bhaduri A. A study of yoga as a nursing intervention in the care of patients with pleural effusion. J Adv Nurs 1984 Mar; 9(2): 127-33.

22. Backon J, Matamoros N, Ticho U. Changes in intraocular pressure induced by differential forced unilateral nostril breathing, a technique that affects both brain hemisphericity and autonomic activity. A pilot study. Graefes Arch Clin Exp Ophthalmol 1989; 227(6): 575-7.

23. Birdel DA, Edgren L. Hatha yoga: improved vital capacity of college students. Altern Ther Health Med 2000 Nov; 6(6): 55-63.

24. Telles S, Desiraju T. Oxygen consumption during pranayamic type of very slow-rate breathing. Indian J Med Res 1991 Oct; 94: 357-63.

25. Nagarathna R, Nagendra HR. Yoga for bronchial asthma: a controlled study. Br Med J (Clin Res Ed) 1985 Oct 19; 291(6502): p1077-9.

26. Nagarathna R, Nagendra HR. An integrated approach of yoga therapy for bronchial asthma: a 3-54-month prospective study. J Asthma 1986; 23(3): 123-27.

27. Singh V, Wisniewski A, Britton J, Tattersfield A. Effect of yoga breathing exercises (pranayam) on airway reactivity in subjects with asthma. Lancet 1990 Jun 9; 335(8702): 1381-3.

28. Behera D. Yoga therapy in chronic bronchitis. J Assoc Physicians India 1998 Feb; 46(2): 207-8.

29. Singh V. Effect of respiratory exercises on asthma. J Asthma 1987; 24(6): 355-9.

30. Joshi LN, Joshi VD, Gokhale LV. Effect of short term pranayam practise on breathing rate and ventilatory functions of lung. Indian J Physiol Pharmacol 1992 Apr; 36(2): 105-8.

31. Bhargava R, Gogate MG, Mascarenhas JF. utonomic responses to breath holding and its variations following pranayama. Indian J Physiol Pharmacol 1988 Oct-Dec; 32(4): 257-64.

Pictures in this article are taken from the book YOGA IN DAILY LIFE THE SYSTEM by Mahamandaleshwar Paramhans Swami Maheswarananda.