Why do people die in the middle of their sleep?

it's acute pancreatitis, when the pancreas bleed when they sleep, they die. it is not because of a nightmare.

There are times during the day when your life signs are higher than other times. Usually, we are at our peak performance in the morning and then again in the evening. We are at our lowest between 3am and 5am and that seems to be the hours when most elderly and very sick people die. There are of course exceptions to the rule, but most folks do tend to die late at night and if they are lucky in their sleep. I think that dying while asleep is a special blessing. Shalom~Adoniah

yeah its so sad when people die during their sleep..and it did happened to my grandpa..i really dont know what causes but some speculations were being brought out..the common one is due to cardiac arrest..which of course arises due to some factors..maybe elevated pressure or whatever in the blood..