During the last thirty years, many doctors and scientists have tried to experiment on yoga and its effects on the body. In fact, first of all they thought that yoga asanas were some sort of gymnastic exercises for the body and muscles. Therefore, the earlier teaching methods of yoga were very dynamic. They had speed and momentum. In the meantime, Swami Sivananda Saraswati of Rishikesh, my guru and also the guru of many swamis who are now teaching yoga around the globe, became a noted writer on yogasana and pranayama in the 1940's.
The first book he printed was 'Pranayama and Long Life: Yogasanas and Good Health'. That book was published by a large publishing house in India and it was circulated throughout the world. In that book Swami Sivananda indicated which asanas are good for which particular diseases. He introduced the idea that yoga is not merely gymnastic exercises, but it has a far reaching influence on all the internal processes of the human body.
At first it was very difficult for the scientific minded people to accept this. How can asanas (postures), pranayama (breathing), and hatha yoga shatkarmas (practices of purification) check 'incurable' diseases like asthma, diabetes, blood pressure; skin diseases like allergic dermatitis, psoriasis; peptic ulcers, duodenal ulcers, gastric ulcers; arthritis, rheumatism? In the beginning it was very hard to believe. People did believe that exercises promote good health, but there was no scientific evidence as to how the asanas worked on the human body.
When Swami Sivananda wrote his book, he gave quite a few hints. The first was that with regular practice of asana, endocrinal imbalances are removed. There are many glands in the human body. Some are called endocrine glands, because they inject hormonal fluid directly into the blood vessels, and others are called exocrine glands, about which we are not concerned now. This endocrine system is very important because it can completely change the structure of the body, the nature of a person, his temperament, and many other things.
Take the thyroid gland, for example, which is situated in the lower part of the throat. It is responsible for controlling the temperature in the body. Usually around the age of twelve it starts functioning, and at the age of seventy or eighty it stops. Of course, it can stop earlier also, say at about fifty eight or sixty. During all these years this gland produces, at the most, a total amount of about ¼ teaspoon of hormonal secretions, which is injected into the blood vessels regularly in minute quantities. And with that tiny amount of hormone you maintain your rate of metabolism, inner body temperature, and emotional balance.
In the same way there are other glands in the body, like the pancreas for the production of insulin, adrenal glands for adrenalin, gonads for sperm and ova. Imbalance in the endocrinal system is a major factor responsible for disease. That is what Swami Sivananda wrote in his book for the first time. Later it was found that he was absolutely correct.
There is another important factor involved in bringing about disease and that is imbalance in the nervous system - the sympathetic, parasympathetic and autonomic nervous systems. In daily life we are more concerned with the sympathetic and parasympathetic. These nervous systems control the impulses, influxes, transmission of efferent and inferent orders. If there is any major imbalance in these two lines, then you have a real problem. These nervous systems are also responsible for controlling and regulating the endocrine system.
Let us talk about the pancreas. This large gland secretes many fluids, the most important of which is insulin, responsible for balancing the sugar assimilation. If there is any imbalance in the secretion of insulin, then the sugar assimilation is not properly regulated, and most of it is expelled. That results in what is called diabetes.
Now, it is the parasympathetic nervous system which is responsible for creating a block in the pancreas. If you overeat and don't do any physical exercise - number one, or when you are under constant stress and strain - number two, then the parasympathetic nervous system becomes underactive. Then its normal functioning is obstructed. As a result, it is unable to send impulses to the pancreas and the pancreas does not produce insulin.
In yoga, what exactly do we do to rectify this situation? Let us proceed very systematically. Yoga means union or connection. Hatha yoga is a science in which two systems in the body are united, are connected. These two systems are known as sun and moon, mind and prana, vital and mental energy. These are the two energy systems which are responsible for our physical existence. These energies are functioning in each and every part of our body. Hence, we have life force, which is dynamic, and consciousness, which is static. Whenever there is any imbalance in these two energy levels, then sickness or disease results.
Prana means vital energy. It is responsible for all the physiological functions of the body, for mobility, body temperature, digestion, excretion, circulation, respiration, etc. For all the activities that are taking place in the body, prana, the life force, is responsible. That is one force in you. If that force leaves your body, you will die. Without prana, there is no metabolism, no anabolism, no catabolism. When there is no prana in your body, that is called death.
The other force in the body is mind or consciousness, through which you think and feel. That force is responsible for knowledge or awareness, and if you do not have that, then you may be alive, but you will not know it. In front of you there may be beautiful flowers with a sweet fragrance, or something rotten and stinking, but you will not know the difference. You are just alive. There is no consciousness, no perception.
So, in the science of hatha yoga, a balance between the life principle and the mental principle is effected. When the mental principle is unbalanced, then you have mental diseases born out of the mind. And when the pranic principle is unbalanced, then you have diseases belonging to the body. The diseases of the mind are known as psychic diseases and those of the body as somatic diseases.
A disease may originate from the mind and go into the body, or it may originate in the body and affect the mind. A disease which originates in the mind and affects the body is called psychosomatic. A disease which originates in the body and affects the mind is called somo-psychic. No disease is purely somatic or psychic, either it is born on account of the imbalance of prana or the imbalance of mind. Therefore, in hatha yoga, what we are trying to do is to create a balance, to bring both the energies into a balanced state, and thereby allow the healing to take place.
Some years ago the teachers used to say that when you do asanas your body gets massaged. For example, in dhanurasana (bow pose), there is a massage of the abdomen and so digestive disorders are removed. I did not really agree with this theory because it is not completely true. Yoga therapy, according to the scientific understanding, takes place on account of the balancing effect which is created by the yoga postures in the nervous system. And by creating a balance in the nervous system, regulation of the endocrines is effected. This is a very simple theory.
Another important point which is misinterpreted in many books concerns the practice of pranayama. They say you store up more oxygen in order to maintain a higher energy level. However, this is not true scientifically. You can store carbon in the body, but you can't store oxygen, because oxygen is a combustible gas. It will create the process of catabolism, and burn away all the tissues of the body. Other researchers and yogis have found in sirshasana the rate of ventilation in the brain is increased three to four times, while the overall consumption of oxygen in the body is reduced to a minimum. So when you do sirshasana you are taught to assimilate maximum oxygen from minimum intake.
In meditation you also consume very little oxygen. When the mind slows and external awareness is diminished, the body becomes quiet and thought vibrations stop. At this time the consumption of oxygen falls very low; that is why they say in yoga you increase the lifespan because you do not exhaust the oxygen stock, the vital capacity, within you.
Another important thing they found was that during sirshasana all the organs and lower limbs of the body were relieved of tension. Ordinarily they are under tension because of their weight. Anything that has weight is pulled down by gravity. However, when you are in sirshasana, the centre of gravity is shifted and there is a counterbalance. The uterus which was pulling downward, pulls the other way. The same applies to the intestines and all other abdominal organs. Of course, if you remain in sirshasana for all the twenty four hours, it is not going to be of any help. But it is relaxing for the whole system if performed for a period of five, six or seven minutes.
I have been teaching headstand pose to quite a number of people on an experimental basis. Once I tried it on a girl who had fibroids. In fibroids, you get several days of profuse menstrual flow. Through the practice of sirshasana you can influence the menstrual flow by rebalancing the pituitary, which is considered to be the master gland. Twenty two groups of hormones are produced by the posterior pituitary alone; I am not talking about the anterior pituitary. These hormones, if not carefully balanced, can create any negative symptom in the body. The regulation and health of the pituitary can be maintained by the practice of sirshasana, because during headstand pose, the circulation of blood to the brain is greatly increased. When you maintain proper circulation in the pituitary gland, it remains healthy.
When I was teaching sirshasana to the lady with fibroids, I knew very well that I was not trying to remove her problem by some miracle. If a type of hormonal imbalance was responsible for changing the structure of her uterus, a rebalance of hormone could eliminate it. This is the way yoga works.
I'll give you another citation. In 1966 I was asked by the Central Government of India to do a research program. I accepted that proposal and in Patna Medical College Hospital, a committee of twenty one doctors with myself as co-ordinator, was formed. The subject that I chose was the effect of yoga postures on coronary diseases. This research was made with about 1,000 patients who were referred for a period of five years. It was conducted by the Head of the Department of Cardiology.
The outcome of the experiment in brief was a drastic reduction in the amount of medication required by these patients, and the practices were not very complicated. They were just the simple practices of padmasana, siddhasana; simple pranayama, breathing in and out, no retention; all the simple backward bending asanas like cobra pose, locust pose; and forward bending poses like paschimottanasana, halasana. Many postures were included. Most of the patients improved greatly when they were practising yoga, and their brainwaves were found to be very positive.
In fact, many patients who came to the yoga class every morning and evening for twenty five minute sessions, found the first thing that came into their mind was, 'Now, I will be all right'. This thought is as powerful, or even more powerful, than hundreds of tranquillisers and antibiotics. Once you get the idea into your head that you will be all right, you will be.
Later, these heart patients were given the practices of pranayama and finally they were taught bhastrika pranayama, rapid breathing with a high count, so that we could check the reaction of the heart.
Coming to a very important point: many times in India we read in the newspapers that some yogi has gone into an underground samadhi, which is completely sealed off, and he remains there for five, ten or fifteen days. In the beginning many thought this was a fraud because they had no way to check it. No one knew for sure whether these yogis were still breathing inside there or not. But now, scientists are able to record the physical parameters through the use of electronic equipment. They can find out if the heart is still functioning, if the radial pulse is working, if there is some sort of movement; what happens to the breath. Now everything can be examined.
How does one stop the heart, and how does he restore the activity of the heart? Is it possible? If so, then several new chapters will have to be added to our medical books to show that heart attack can be averted. And once an attack has taken place, the heart can be restored to normal function.
What actually happens when a person has been declared clinically dead for ten days, and then he comes back to life? How does that restoration take place? In yoga it is said that when the mind drops, the breath also drops. That is the state called kevala kumbhaka. It means spontaneous retention of breath. The moment the mind becomes active, the breath is also resurrected, because the mind and the breath are two companions. They live together, move together, fly together and die together. If you resurrect the prana, you resurrect the mind; if you resurrect the mind, you resurrect the prana.
Some yogis start by controlling the pranas, they are called hatha yogis. Others start with the mind, they are called raja yogis. Through the mind, you can influence the prana, that is raja yoga. Through the prana, you can influence the mind, that is hatha yoga.
In yoga there is a small but very important gland situated; behind the eyebrow centre above the medulla oblongata. Physiologically it is termed the pineal, but in tantra they call it ajna chakra. Ajna means 'monitor or command'. Ajna chakra is therefore known as the commanding centre.
If you concentrate at the eyebrow centre, gradually your pranas become focussed and centralised, and you begin to see a small light. It is like a halo. When that halo is there, it means that ajna chakra is contacted. If ajna is not contacted, you will not see the light there. You will feel some pressure, but you will not see the light. When you are able to see a constant glow of light, sometimes oval, sometimes round, that means ajna chakra is coming under your influence; that is point one.
Point two: The more the light glows, the more the breath is suspended. And there is a point when the breath stops altogether; you don't breathe at all, there is no breath. And when there is no breath, after some time, the heart stops, but consciousness remains. That is the key. You are not physically functioning, but you are aware. And what is that awareness? Just illumination, that is all. There is no name and form, time and space, only constant awareness of light. As long as the light is there, consciousness will remain, and the prana, the life force, will be there in the seed state.
If at any time the light vanishes, the yogi will die there. Without illumination, no restoration of the heart can take place. So, when the light starts fading, the yogi comes out. He begins to relate himself with time and space. And as soon as he becomes extrovert he rings the bell to signal that the vault should be opened.
Now, that light is the indication of two things. Firstly, that the prana is still in the body in the unmanifest state. And secondly, that the yogi is aware of the light, and of himself. This is due to the influence of ajna chakra.
In yoga, there is a strong emphasis placed on the development of ajna chakra. Concentration on the eyebrow centre is known as shambhavi mudra. It can also be developed through trataka, There are other ways as well. If you can learn to handle ajna chakra properly, you can control all the different systems in the body: nervous system, endocrine, respiratory, circulatory, digestive, and excretory systems, everything can be managed, and that is the exact methodology of yoga. Of course, we do asana, pranayama, mudra, bandha, meditation, concentration, relaxation, but the main and most important point is that we learn to master this gland called the pineal, which is the seat of ajna chakra.
Let me give you a simple analogy in order to make it more clear. The pituitary gland is the disciple. Pineal gland is the guru. This should be the relationship. As long as this relationship is abiding, everything goes all right. But when the pineal gland becomes subservient to the pituitary, then you have emotional, mental, psychic and physical problems. Thyroid overacting/ underacting, adrenals overacting/underacting, metabolism totally out of balance, and you do not know exactly what is happening. You take drug after drug, antibiotics, sedatives, tranquillisers. Doctors do not know exactly what is wrong either, because they are only taught to treat this body as bone, marrow, blood and flesh. They are unable to deal with the diseases at a subtler level.
In yoga, we consider this body as a manifestation of two basic energies - mind and prana. To maintain a balance between these two, the pineal should be strengthened by concentration on ajna chakra.