The most common factors have formed a nightmare

1, the body such as calcium, irregular heartbeat, breathing disorder.

2, sleeping posture is wrong, such as rest, stomach, have to sleep, for coverThe quiltToo thick or hand on the chest.When people from deep sleep wake up, and the central nervous is paralysis, people are most likely to produce can't turn, don't shout out not state.

3, sleep, stress, such as environment make the dreamer has pressure (bed roof beam), a strange environment, etc.