Gosh Petunia, I sure hope not! I'm not really sure, you may want to ask your doctor that question though. Or maybe someone here knows? I know that under stress the hormone cortisol is released, which I have read can cause blocked arteries, among other health problems. I'm not sure if it applies to stress caused by dreams.

I sure do know what you mean about the pounding heart though after a nightmare!

Sujin