The phenomenon of insomnia can be controlled by the practice of yoga nidra. We often suffer from a delusion that we do not sleep. In fact, a lot of scientific work has been done on this. Many subjects were exposed to scientific experimentation and all these subjects were supposed to be suffering from insomnia. From the scientific exposure it was found that they were really sleeping, because when you sleep, delta waves operate in the brain.
When delta waves operate, it means you are sleeping. In different states, different waves operate. During the process of active thinking, during the processes of relaxation, during deep sleep, thought waves are of different frequencies. These frequencies are known as beta waves, theta waves, delta waves and alpha waves. Now these waves are less and less in frequency as they alternate. This leads some people to have a dreadful feeling that they do not sleep, but they do sleep.
You must remember one thing, however. Insomnia is a physical as well as mental phenomenon. When you do not sleep, it is physiological, but when you sleep, but do not believe that you sleep, it is psychological. If you train someone in the practice of yoga nidra, then that person can get rid of this psychological worry.
Another important factor which you have to know is – sleep is a state of consciousness involving physiological states. Sleep is not a physiological state; it is a mental state. At the same time, the biological situation influences the psychological state. A certain amount of disharmony is created in the secretions and those secretions when they pass through the blood vessels can cause inertia in the coronary system, this can also cause what we call bad sleep or insomnia.
When you train a person in the practice of yoga nidra, he develops a quality of controlling sleep through mental processes. A simple illustration: when you do not get sleep you usually take a few sedatives which work through the blood vessels or through the nervous system and create a natural state of sleep by influencing the biological processes. Another possibility is that you do not sleep well, but you believe that sedatives are no good, because you believe that in the course of time the system resists or attains immunity to sedatives. All these sedatives have an adverse effect and do not work in the same manner on different areas of the body. You then try to find an autonomous method. By this autonomous method, you try to create an automatic sleep.
Yoga nidra is a powerful system and you hear this from many people. You say in your mind, “Why should I not try this?” If I can make myself sleep through yoga nidra I am training my mind. Through the training of the mind, I am training the biological functions. Thus, through your effort you create a voluntary state of sleep.
These are the two possibilities which I put before you. In both cases, sleep is brought from the outside. In both cases, sleep is not voluntary. In both cases, sleep is involuntary. In the first example, it was created via biological changes. In the second example, it was created via psychological processes. In the first example, you first created biological changes and then you influenced the mind. In the second example, you first influenced the mind and then created the necessary changes in the body. Both are alright, with one difference. In the first one you depend on the existence of external chemicals, the far reaching reactions of which you are not sure about. In the final analysis, yoga nidra is a very harmless method.
Another important thing which we have noted: ordinarily when sleep comes, the person’s brain waves slowly come down to the level of delta. From the normal brain waves there is a sequence – beta, theta, then delta. That is: now you are awake, now you are thinking, now you are asleep. In yoga nidra the process is different. From normal waves you come down to alpha waves first. From alpha waves, you slowly come to delta waves. Delta waves have a slightly different frequency than alpha. In alpha waves there is a quality of relaxation. This is a very important thing that you should know.
Most people sleep without resolving their tensions, because they are coming down from beta to theta and delta all at once. They have not cultivated alpha waves and therefore their body and mind are not relaxed. Relaxation takes place when alpha waves become intense. In the ordinary way, the process involves coming down from normal wavelengths to delta wavelengths. In yoga nidra, normal brain waves come down to alpha waves – relaxation. These alpha waves gradually revert to delta. That is why the quality of sleep created through yoga nidra is of a higher quality as far as its reflections on the body are concerned. That is why it is not known as nidra. It is known as yoga nidra. Nidra means sleep, no matter how or why. Yoga Nidra means sleep after throwing off the burdens.
13 September 1980, Zinal, Switzerland