A Falling Sensation
Have you ever lain in bed and just as you are about to fall asleep, a sudden sensation of falling or a dream of falling through a deep hole overwhelms you? The medical term for this phenomenon is called a "Hypnic Jerk".
"Hypnic Jerks" are a type of involuntary muscle movement that occurs when we fall asleep. When the muscles twitch, it gives us a false notion of falling from a height, and dreams or hallucinations accompany the process. We may abruptly wake up, but since "Hypnic Jerks" usually emerge during the first stage of the sleep cycle, we quickly return to sleep after calming down. Many people do not even realize that they have endured "Hypnic Jerks", because muscle twitches is so short-lived they are forgotten, or are not noticed at all during sleep.
According to research conducted by the American Academy of Sleep Medicine, about 60% to 70% of people occasionally experience "Hypnic Jerks". Although "Hypnic Jerks" are very common, there is still no definitive explanation as to why it happens. Some scholars have put forward some theories, one of which is that muscles relax during the onset of sleep. The brain misinterprets the signal and believes that the body is falling. The body's self-protection reflex tries to grasp onto something during the fall, and then sends out a message of muscle tightening, causing sudden muscle jolt.
Squashed by the Paranormal
Has the feeling of being awake in bed, but you can neither move nor speak ever occurred? This phenomenon is frightening, and some people have even compared it to "being squashed by ghosts." The medical term for this phenomenon is called "Sleep Paralysis".
Why does "Sleep Paralysis" happen? When the sleep cycle enters REM, the muscles of the body and limbs completely relax and is said to be in a state of "paralysis" (REM Atonia). If we suddenly wake up before the rapid eye movement phase ends, the brain may have become alert, but the body is unable to move and speak. In some cases, people may have difficulty in breathing. The ordeal may last for a few seconds to several minutes, after which the body will regain full function and is free to move again. Anyone may experience "Sleep Paralysis", it may occur once in their lives, or it may happen several times a year. Studies have pointed out that people start to experience Sleep Paralysis at around 14 to 17 years of age.
Scholars generally believe that when the body is too fatigued or stressed, “Hypnic Jerks” or “Sleep Paralysis” becomes more prevalent. You don't want to frequently scare yourself by "falling" or "be squashed by ghosts"? Then you must have regular work and rest habits, maintain adequate sleep and avoid drinking alcoholic or caffeinated beverages before going to bed. If the phenomena mentioned above become frequent or severe, and lead to insomnia or anxiety, you should seek medical assistance for professional advice as soon as possible.
ﾠNational Sleep Foundation - https://www.sleep.org/articles/hypnic-jerks/
 American Academy of Sleep Medicine (AASM) - http://sleepeducation.org/news/2013/08/22/sleep-starts
 Live Science - https://www.livescience.com/39225-why-people-twitch-falling-asleep.html
ﾠAmerican Academy of Sleep Medicine (AASM) - http://sleepeducation.org/sleep-disorders-by-category/parasomnias/sleep-paralysis/diagnosis-treatment