I remember a trial held in a hospital in England. A group of patients recovering from heart surgery were divide and half of them were told that prayers were being said to aid their recovery and half were told nothing. The group who were told they had prayers being said took longer to recover than the other group.
I know it was a tiny survey and of little consequence but interesting non the less.

@Moravian I looked into that after you told me about it. Interesting study, indeed. I still maintain that if one believes firmly enough that their own prayer directed toward themselves is going to be effective the placebo effect becomes involved.

In fact, that rabbit hole goes quite deep. There are many documented examples of people performing superhuman feats through mental and physical conditioning, including imagery designed to influence their abilities through believing that they can do it.