Essentially any bodily process that can be measured can potentially be controlled through biofeedback. It can be effective in relieving many pain problems as well as anxiety. The main concept of biofeedback centers on the idea that you may not be able to control what goes on around you, but you can learn to alter the way that you respond to it.
When undergoing biofeedback, you are connected to a machine that informs you and your therapist when you are physically relaxing your body. Sensors placed over specific muscle sites will allow the therapist to monitor the tension in your muscles, heart rate, breathing pattern, the amount of sweat produced, and body temperature. Any one or all of these readings can let the therapist know if you are learning to relax.
The ultimate goal of biofeedback is to use this newly learned skill outside the therapist's office. If learned successfully, biofeedback can help you control your heart rate, blood pressure, breathing patterns, and muscle tension when you are not hooked up to the machine. Once you learn how to self-manage your stress in a healthy way, you can use relaxation techniques to help you de-stress before bedtime, allowing you to go to bed with a clear head and without nighttime teeth grinding.