in addition, those experiencing stage fright will have an increase in blood pressure, which supplies the body with more nutrients and oxygen in response to the "fight or flight" instincts. this, in return, causes the body to overheat and sweat. breathing will increase so that the body can obtain the desired amount of oxygen for the muscles and organs. pupils will dilate giving someone the inability to view any notes they have in close proximity; however, long range vision is improved making the speaker more aware of their audience's facial expressions and nonverbal cues in response to the speaker's performance. lastly, the digestive system shuts down to prepare for producing energy for an immediate emergency response. this can leave the body with the effects of dry mouth, nausea, or butterflies.