Biofeedback has been around a long time and is a great way to become more aware of how your body reacts to stress and anxiety. It also helps you discover what you can do to train your body to respond differently and in ways that are less stressful for both your body and mind.
When you are learning Biofeedback, you are hooked up to various sensors—such as a sensor to measure perspiration, or a sensor to measure muscle activity—that then feed this information back to recording or measuring devices that you can see or hear. These devices let you know how you are doing and can be viewed on a computer screen or light, or perhaps via an auditory response like a tone or other sound. Many times the feedback might just be a number to let you know how high or low, good or bad, strong or weak a signal is.
One example of biofeedback is to have a headband of electrodes placed on the forehead that measures the muscle activity in the face. This is a great method for discovering if you hold tension in your facial muscles and can help you realize subtle things, like that you squint your eyes when you are thinking too hard, or it may pick up on activity that allows you to know that you clench your teeth when you are asked about work, which could explain the tension you keep having in your jaw or the headache you keep coming home with each night.
Once the biofeedback information is known, then you have data to help you zero in on specific relaxation techniques that can be used to remedy the problem. For instance, if you discover that you clench your jaw, you can begin practicing activities during your day that help you stay aware of your jaw clenching and how to release the tension there frequently and repeatedly throughout your day.
There are biofeedback counselors across the nation who are trained to help you with your stress and anxiety. Some can be found via the "practitioners" link through The Association for Applied Psychophysiology and Biofeedback, Inc., or you can find a number of devices to monitor your own biofeedback by doing a Google search for "biofeedback home units".
Gaining insight into the way your body might be unconsciously reacting to stress is extremely helpful in knowing what steps can be taken to remedy the problem.
Thanks to Faraz Kahn for the above image - Biofeedback