Pain, such as that caused by a cramp or choking, sends a signal to the vagus nerve, which in turns signals the heart, slowing it down so much that the person faints.

• 抽搐或者窒息引起的疼痛会向迷走神经传送信息，然后这种信息又会传到心脏，导致心跳速度减慢，这样就会引起昏厥。