A very powerful treatment for stress, biofeedback is based on the clinical observation that human beings have an innate potential to control some of their autonomic functions. For example, with biofeedback therapy you can be trained in a matter of hours or days to change the temperature of your hands, at will, by several degrees. You can learn to alter your brain waves, reduce the frequency of asthma or allergy attacks, or manage pain. You can also learn to prevent migraine headaches. As well, various studies have shown that biofeedback therapy can effectively help to reduce some of the complications associated with irritable bowel syndrome, tension headaches, and strokes. This means you can be taught to control, at least to some degree, the supposedly involuntary processes (e.g., blood pressure, heart rate) that increase when youre under stress.

Biofeedback relies on special equipment with sensors that track skin temperature, muscle contractions, and brain waves. The biofeedback machine feeds back your efforts at control in the form of a signal (e.g., a buzz). Once youre connected to the biofeedback machine, youre instructed to extinguish the signal. Because you have no idea how to do this, you must rely on trial-and-error to determine how to relax in order to stop the signal. You eventually learn to control your responses to stress without the equipment. Most biofeedback sessions with a trained therapist are scheduled weekly and last from 30 to 60 minutes.

Several different types of biofeedback machines can provide information about the systems in your body that are affected by stress.

Galvanic skin response (GSR) biofeedback measures your skins electrical conductance that is related to sweat gland activity. You probably know this form of biofeedback from its use in lie detector tests. As a small electrical current is applied to your skin, the GSR equipment measures changes in the levels of water and salt released from your sweat glands. The more emotionally aroused you are, the more active your sweat glands are and the greater your skins electrical conductivity is. GSR is frequently used to treat stress, anxiety, phobias, panic, excessive sweating, stuttering, and poor athletic performance.

Temperature feedback utilizes a machine that monitors skin temperature. A sensor is attached to your finger or toe. If youre anxious or nervous, your skin temperature will drop as blood redirects from your hands and feet to your internal organs and muscles. If you're calm and relaxed, your skin temperature will rise as blood returns to your hands and feet. Temperature feedback can be invaluable for treating stress, migraine headaches, and circulatory disorders like Raynauds disease, which is a condition characterized by excessively cold hands and feet.

An electromyogram (EMG) measures muscle tension. Two electrodes (or sensors) are taped onto your skin over the muscle to be monitored (e.g., your jaw muscle). When the electrodes measure muscle tension, the device produces a buzz, beep, or colored light. You can hear or see continuous monitoring of your muscles activity as you learn what tension feels like when it begins to mount. You can learn to eliminate the tension before it worsens or causes problems. EMG is particularly good for treating neck pain, jaw pain, tension headaches, backache, and stress-related conditions like ulcers and asthma.

An electroencephalogram (EEG) monitors brain wave activity. Because alpha waves are characteristic of states of relaxation (versus beta waves, which are characteristic of states of wakefulness), you might find relief from anxiety, stress, and insomnia by learning to increase your brain's alpha wave activity.

Biofeedback is likely to be more effective when combined with relaxation techniques and cognitive-behavioral psychotherapy. In this way, you can discover how to control your emotional reactions while also exploring how your thinking and behaviors contribute to your stress.