Here is the answer:
The average healthy person can experience an extreme array of anxiety and very uncomfortable sensations while giving a speech and is in no danger of ever losing control, or even appearing slightly anxious to the audience. No matter how tough it gets, you’ll always finish your piece-even if, at the outset, it feels very uncomfortable to go on. You won’t become incapacitated in any way.
The real breakthrough happens when you fully believe that you’re not in danger and that the sensations will pass. By asking for more, you’re saying: “I realize that you [the anxiety] hold no threat over me.”
What keeps a panic attack coming again and again is the fear of the fear-the fear that the next one will really knock your socks off and the feeling that you were lucky to have made it past the last one unscathed.
Because they were so unnerving and scary, it’s your confidence that’s been damaged by previous anxiety episodes. Once you fully understand that you’re not under any threat, then you can have a new response to the anxiety as it arises while speaking. There’s always a turning point when a person moves from general anxiety into a panic attack, and that happens with public speaking when you think to yourself: I won’t be able to handle this in front of these people.