For years Westerners have heard reports about amazing feats of physical control performed most frequently by Indian yogis. They were, it was reported, able to stick large needles into parts of their bodies and not bleed or experience pain. Others were reported to have been buried in coffins in the ground for extended periods of time and, long after the normal consumption of air should have left them dead, emerged alive and healthy. Still other yogis were reported to be able to walk over burning coals and experience neither pain nor blistering. Most people doubted these reports or dismissed them as magicians' tricks. But some researchers had learned from their own work that such reports might be true.
These exotic stories and common individual experiences are part of the impetus to the development of the new science of biofeedback. During the sixties biofeedback studies demonstrated how people could exercise substantial influence over bodily states that were formerly thought not to be subject to conscious control.
Researchers in biofeedback have discovered that it is possible for average people, not just yogis, to learn to control voluntarily heart rate, muscle tension, sweat-gland activity, skin temperature, and a wide range of internal physical states normally considered to be under involuntary control by the autonomic nervous system. The procedure by which the trainee learns to control these physical states is not very complex. Electrodes are attached to the skin of the person receiving the training so that a biofeedback machine can monitor some of his physiological functions, such as heart rate, brain waves, or muscle tension. The machine gives the trainee visual and/or sound signals that indicate what is happening to the physical function.
If, for example, you were learning how to alter your heart rate, a tone might sound at a higher frequency as the heart rate increased, and at a lower frequency as the heart rate declined. Initially, it might seem to you that the higher and lower frequency sounds were purely random, that there was no connection between what you were thinking and your heart rate. But soon you would become aware that you were experiencing certain thoughts or feelings when your heart rate declined, or that certain physical postures had an effect. Over time you would learn to exercise sufficient control over the physiological function to raise or lower the sound (and your heart rate) pretty much as you wished.
To date, every physiological function that can be accurately and predictably measured and "fed back" to trainees has been subject to learned control. Using biofeedback, people have been taught to reduce high blood pressure, eliminate migraine headaches, control irregular heartbeats, increase and decrease blood flow, cure insomnia, and control numerous other "involuntary" physiological functions.
Elmer and Alyce Green of the Menninger Clinic, pioneers in the field of biofeedback, have reported experiments in which trainees learned to control through their own volition a single nerve cell. They believe that biofeedback technique has clearly demonstrated the physiological principle that "every change in the physiological state is accompanied by an appropriate change in the mental emotional state, conscious or unconscious, and conversely, every change in the mental emotional state, conscious or unconscious, is accompanied by an appropriate change in the physiological state." In other words, mind, body, and emotions are a unitary systemó affect one and you affect the others. As Dr. Barbara Brown, another pioneer in biofeedback research, states:
If some medical researchers are now teaching hearts, or the minds of hearts, to reverse a pathological condition, then medicine must be learning that relationships between mind and body are more powerful than they once thought. The concept of "psychosomatic" is generally accepted as indicating the mental origin of physical pathology; research into biofeedback is the first medically testable indication that the mind can relieve illnesses as well as create them.