Nightmares are caused by palpitations, in which the heart beats fast and slow during sleep, which will correspondingly lead to the two most common nightmares: being chased by people and falling by flying people (the illusion of hanging heart and sinking heart caused by palpitations). Like all psychological activities, dreams are the reflection of objective things in the human brain, and nightmares have no warning. For example, my heart used to beat faster every day. When I sleep, I have nightmares about being hunted down day and night. Later, after taking sleeping pills that can slow down the heartbeat, the heartbeat stopped during the day and I stopped having nightmares when I slept.
People who plan to go out dream of being awakened by nightmares and suggest not to go out. delay
People who are preparing for the exam dream of being awakened by nightmares, which shows that they are not afraid of difficulties and have confidence that they will pass the exam one day.