One way to manage your adrenaline rush before your presentation is through mind exercises, or in other words, positive self-talk. Before you stand to present, try saying the following to yourself.
“I am about to give this group a gift – one from which they will benefit. They will be better off for receiving this gift, and they will thank me for giving it to them. I am glad I have the opportunity to share my knowledge with them.”
I'm not sure who originally wrote this, however, thanks! Sure beats worrying about my zipper being down.