When you take another step or wave your hands you control these actions. There are some other body functions that are controlled by your nervous system. You never think about making your heart beat faster, it just happens.
Biofeedback training is used to help prevent or treat conditions, including migraine headaches, chronic pain, incontinence or high blood pressure. It is a technique that can help you to gain more control over involuntary funcions of your body.
The idea behind biofeedback is that, by harnessing the power of your mind, you can gain more control over your health.