@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.

@Metahuman I agree with your second paragraph but it's not prayer is it. I once read of Buddhists being able to survive sub zero temperatures in flimsy clothing by using mind control to heat their bodies.
Don't know if there is any truth in it.
If prayers work, which is unlikely, it must be mere coincidence or as you say a placebo effect.