If you are someone who has been ducking presentations because you fear speaking before groups, you're far from alone. In one survey, researchers at Purdue University found that fear of public speaking was among the top ten fears (out of a list of 131).[1]
In the "knew it all along" category is the study done by Cedars-Sinai Medical Center, which found that many mental conditions can trigger the physical condition of heart stress. The worst of all was asking people to give five-minute talks about their personal faults and bad habits to two observers. Moral: Choose a different subject for your speeches. [2]