Hyper-arousal also starts with a natural and normal response to danger, the “fight or flight response.” After an injury or accident, this “fight or flight” response might not turn off, even when the child is safe. After a scary situation like being injured, a child might have the feeling that something bad could happen again at any time, or he might jump at any loud noise. The physical feelings that go along with hyper-arousal (e.g., heart racing) can feel scary themselves.