Fear and anxiety are normal, yet distinct, human emotions. The difference between the two is that the object of fear can be identified and removed, at least theoretically. If a person is afraid of the dark, he or she can simply turn on the lights. Anxiety can be further differentiated into two types, existential and neurotic. Neurotic anxiety is characterized by a fear disproportionate to the object involved.
Performance anxiety is an example of a neurotic anxiety.
The human body is equipped with a nervous system which responds automatically to a threat, permitting the person to fight or flee the situation as appropriate. Unfortunately, the brain does not distinguish between a physical and a psychological threat, so this fight or flight instinct is called into action regardless of whether the threat is a shark attack or a concert performance. When a person feels threatened, a chain of physiological responses takes place very quickly to prepare the body for action. Sweating helps cool the body and prepares it for a speedy flight from the threat. Faster breathing provides more oxygen for the muscles and the heart to work harder, but this often also leads to a drier mouth.