The sympathetic system

The sympathetic system is the arm of the autonomic nervous system that prepares the body for action and movement. When faced with a danger or a difficulty, this system comes into play; the heart speeds up, the muscles tense, and the body prepares either to fight or to flee. Sympathetic activation is natural and necessary; the problem is this arousal staying constantly on. This system can be thought of as the body's gas pedal. In a balanced nervous system, sympathetic activity rises when needed and then settles.