It’s my understanding that everyone has sleep paralysis - the brain “switches off” the body (apart from essentials: breathing, heart beat etc) so you don’t come to grief acting out your dreams. What we call sleep paralysis is when you wake, but your body hasn’t been switched back on.

I used to have horrible sleep paralysis nightmares quite often. But then I read about what it really is, and I stopped having them. It was like my brain realised it was out of sync and corrected itself.