鬼压床 = Sleep Paralysis

Have you ever had this situation whereby you are already awake, but unable to move yourself? As if 鬼压床? Several minutes passed and you are still stuck, feeling extremely difficult to breathe, as if you are gonna suffocate to death? Finally, i found the answer to the above questions, thanks to my colleague.

So, why can the above situation happen?

Apparently, when someone falls asleep, they will go through different stages of sleep, one of them being the Rapid Eye Movement (REM). During REM, the release of certain neurotransmitters (norepinephrine, serotonin, histamine) is completely shut down. Thus, since the motor neurons are not stimulated, the skeletal muscles become paralysed/extremely relaxed (REM atonia). This is one of the body's defense mechanism because dreaming takes place during REM. When this happens, the person may act out the movements in the dream (e.g. sleepwalk). However, this REM antonia prevents the person from acting out the dangerous movements enacted in the dream.

The main point is...

Sometimes when we take a nap in the afternoon or are suffering from sleep deprivation, sleep paralysis occurs. So, for example, this person has taken an afternoon nap and has just fallen asleep at night. As usual, he will go through the various stages of sleep including REM. Since the sleep pattern has already been disturbed, when he "awakes", the brain has already awaken from REM, however the body paralysis still persist. And since this paralysis can persist from several seconds to several minutes, by this time, the person would have felt panicky for he is unable to move, as if 鬼压床. Moreover, since during REM, our heart rate and breathing rate are irregular, thus having a feeling that its extremely difficult to breathe.

So now i know that it isnt 鬼压床, but sleep paralysis :D