The most common causes of nightmares are

1, the body such as calcium deficiency, irregular heart rate, respiratory disorders.

2, the sleeping position is not right, such as high pillow, prone, sleeping with the head covered, the quilt is too thick or the hand on the chest. When people wake up from deep sleep, and the central nervous system is paralyzed, people are most likely to produce a state of being unable to turn over and shout.

3, sleep pressure, such as the environment so that the dreamer has a sense of pressure (there is a beam on the top of the bed), strange environment.

(Editor in charge：constructions)