is normal when after a day of intense physical and mental activity, we have to relax and go to bed, from the time the body goes into a state of total relaxation, but the continuous brain activity, receiving sensations body, being relaxed, the brain interprets it as a "sense of imminent collapse", even prepared to "feel" the hit, at that time, sent a rush of adrenaline that the body reacts with its defense mechanisms, and breaks the "bounce" that awakens us and that's when we realize that there is no fall, no nothing, just a strange feeling in our own bed. This type of "hypnagogic paralysis" is sometimes so strong and intense, that the brain receives signals and sensations of true paralysis with inability to move arms and legs, so it sends alarm signals that activate neurological senses (hearing, sight , etc.) in order to have guidance or a reference point, but now the body without being able to move as deep relaxation in which key, causes the brain to return true feelings of inability to move, it breaks the cerebral alarm and adrenergic discharge with the movement that is recovered.
The final impression is that there was something about the body that would not let him move and breathe, this is the famous "Raising the dead", which is not to climb on us chocarrero a ghost or spirit, but a normal physiological condition that combines extreme body relaxation and a large brain activity.
