Hello everybody!
Many people have experienced waking up in the middle of the night powerless to move. Although they are awake and fully aware of what is going on around them, they are completely immobile. Many felt the visible or invisible presence on it or in the room. It is extremely disturbing feeling and the person is experiencing such an experience, terrified.
Sleep paralysis or sleep paralysis is a momentary inability to move the limbs, trunk and head despite being fully conscious. It can occur when someone is asleep or, much more rarely, when he wakes up.

Paralysis of the entire body, except for the eyes
Heaviness on chest
Inability of speech.
All this happens while you are awake and therefore causes a terrible sense of fear. To make matters worse, these nightmares usually include hallucination.
Other factors that affect sleep paralysis are falling asleep, lying on the back, feeling stress or deviation from normal sleep patterns, as for example due to night work, jet lag, caffeine or alcohol.
It occurs when the brain wakes up during the so-called REM sleep, and the body remains paralyzed. The person is aware of everything, but can not move, and if you get involved and hallucinations, can be really scary.
Sleep paralysis is common and occurs in up to eight percent of the entire population.
Episodes of sleep paralysis last only four to six minutes, but just like panic attacks, may impress a person.
About 30% of the younger population experienced sleep paralysis at least once in their lives.
More likely to occur younger people.
It can last from several minutes to several hours.
People are also experienced, felt or seen, the presence around them during a paralyzed state. Seized them fear and some of them have stated that they demonic forces tried to possess the soul, and are trying to break or suppress.
In some cases, people feel pressure, or a feeling of suffocation, followed by difficulty in breathing. In some instances, this escalates into sexual abuse or rape.
During an attack of paralysis can be an odor.
A small percentage of the people experiencing sleep paralysis to the extent where it becomes a real problem. Such people avoid going to sleep, become anxious when entering the bedroom and think about when it will happen again.

The reason sleep paralysis may explain tales of ghosts and aliens that has a strong sense of presence, usually harmless, the victims usually experience during an attack. You mentioned unusual kinesthetic sensations, such as feeling that they're being pulled out of bed, vibrating, flying or falling. These episodes can sometimes lead to the feeling that you are out of your body. Sleep paralysis can be scary, but never dangerous, and thankfully, episodes usually last only a few seconds.
Although the cause of the syndrome is unknown, there is speculation that it occurs when the reticular formation of the brain stem, usually an important regulator of sleep and wakefulness, does not exclude the right time. This area, which joins the spinal cord, can temporarily awry and cause hallucinations - but no one knows why the symptoms manifest themselves as growling or explosion. Though loud, the noise is usually not painful or dangerous, and usually is not an indicator of certain neurological disorders. Stress and fatigue can trigger episodes, which usually stop in good time and leave the belief that the phenomenon, very unusual.
Have a good day / night!