The sympathetic nervous system is a major branch of the the autonomic nervous system known to initiate a number of functions known as ‘fight or flight’. The sympathetic nervous system is also known to generate energy in a number of forms as well as response to stress. The sympathetic nervous system is balanced in a ‘push & pull” manner with the parasympathetic nervous system. The parasympathetic nervous system is known to control relaxation & vegetative function after fight or stressful event.
Other than preparing the body to cope with emergencies, the sympathetic nervous system serves other vital purposes. For example, standing up after being in a sitting position for a long time must be accompanied with increased blood pressure, or a person can go unconscious. Most people have either experienced or observed lightheadedness when standing suddenly. Without the proper functioning of the sympathetic nervous system, effects like these would be greatly magnified. This system also prepares the body for waking and action after a sleep cycle, as well as increasing heart rate and perspiration during exercise.