== Duration: minutes vs. hours == 

 The article currently says: 
   "The autonomic nervous system's physiologic state (see below) leading to      loss of consciousness may persist for several minutes, so:     If sufferers try to sit or stand when they wake up, they may pass out again     The person may be nauseated, pale, and sweaty for several minutes or hours" 

 This is confusingly vague, and unsourced. My experience is that an episode of of vasovagal response typically lasts 3-15 minutes, but can persist indefinitely, at least a couple hours. What good sources are there for improving this aspect of the article? -