In the episodes with Jiraya, Naruto, and Sakura searching for Orochimaru, they meet a girl whose brother was taken by Orochimaru. At the end of the fight with her brother, she faints, but a second later, as they are leaving, she is screaming, fully awake. It is impossible for a person to wake up after fainting a second later. The human body just doesn't work like that.