The term “biofeedback training” came into use, around 1969, when it was modified to be a useful tool in the teaching and learning of automatic adjustment processes that involves training. In a restricted sense, it is possible to conceptualize feedback through an etymological view. From the radical feed, alimentary, and the radical back, back, originate a feedback from a system. In popular language, the term feedback can also be considered as providing information about the state of a system. In educational and business environments, biofeedback training is a tool for the development of deep relaxation and stress management, processes that are important in preventing stress-related illnesses. In all applications, the goal of biofeedback training is self-regulation – learning how to control both physical and mental requirements for better and healthier functioning.