“The autonomic nervous system also has two divisions called the sympathetic nervous system and the parasympathetic nervous system. Stimulation of the sympathetic nervous system produces bodily arousal, whereas activation of the parasympathetic nervous system is more concerned with recovery from arousal, with conserving energy rather than expending it.”

“Famed Harvard physiologist Walter B. Cannon,” Mindstein continues, “called the sympathetic nervous system your ‘fight or flight’ nervous system. He meant that stimulation of the sympathetic nervous system prepares you to either fight or flee. Among other things, stimulation causes your heart to pump faster, your breathing to increase, your pupils to dilate, your palms and armpits to sweat, and inhibits your digestive processes.