Betablockers are for those who want a quick emergency fix (not judging, they have been good help to me as well). A 20-50 minute aerobic workout has the same net effect for many (healthily burning adrenaline instead of using high blood pressure medication to reduce anxiety).

Be sure to check Dr. Medina's brain rules for presenters: http://www.slideshare.net/garr/brain-rules-for-presenters