Probably to some people once in a lifetime experience. For me absolutely not, I have had countless. Just looked it up again because I just had 2 during my nap. For me it only happens during nap. My brother who also had sleep paralysis almost every day he died At age 20, just after waking up and then drop dead. That was 12yrs ago. To this day I'm frightened that will happen to me as well. I think there is a link with the heart not just the brain with this sleep paralysis , just found out have genetic problems. It's an awful experience because seconds feel so long, every time I come out from it I get up right away scared I might fall asleep again.