A person seeking to regulate his heart rate would train with a biofeedback device set up to transmit one blinking light or one audible beep per heartbeat. By learning to change the rate of the flashes and beeps, the subject would be subtly programmed to control the heart rate. Patricia Norris, Ph.D., Clinical Director of the Biofeedback and Psychophysiology Clinic at the Center for Applied Psychophysiology at the Menninger Clinic in Topeka, Kansas explains that the self-regulation skills acquired through biofeedback training are retained by the individual even after the feedback device is dispensed with. Biofeedback practice is like taking tennis lessons. If you stop taking the lessons but continue playing, your game will improve. With biofeedback, it works the same way. The more you practice, the better you get.

  The effects of biofeedback can be measured in a variety of ways: monitoring skin temperature (ST) influenced by blood flow beneath the skin; monitoring galvanic skin response (GSR), the electrical conductivity of the skin; observing muscle tension with an electromyogram (EMG); tracking heart rate with an electrocardiogram (EKG); and using an electroencephalogram (EEG) to monitor brain wave activity. Electrodes are placed on the patient's skin (a simple, painless process). The patient is then instructed to use various techniques such as meditation, relaxation, and visualization to effect the desired response (muscle relaxation, lowered heart rate, or lowered temperature). The biofeedback device reports the patient's progress by a change in the speed of the beeps or flashes.

  Normal, healthy, "relaxed" readings include fairly warm skin, low sweat gland activity (this keeps the skin's conductivity low), and a slow, even heart rate. Biofeedback technologies utilize computers to provide a rapid and detailed analysis of activities within the complex human system. Biofeedback practitioners interpret changes in these readings to help the patient learn to stabilize erratic and unhealthy biological functions.