Falling Sensation When Sleeping

I think this kinda sensation not only happened to me, but to others to. It's a sensation that happened when you are sleeping, as if you are falling down from a high place, or falling down from a motorbike and it cause your body to make a body reflex and wake you up. This sensation is called hypnic jerk, and its very normal for people to get this when they sleep. Mostly, this will happened when you are tired and you sleep, or you are sleeping in a uncomfortable manners. As for me, it always happened when i slept in a lecture hall, or in LRT on my way to Uni =p. Its sometimes very humiliating if you suddenly jerk at the crowd. And if happen on bed, i may accidentally kick or slap someone. Lol..

So, why does this happened actually? Its because, let say i'm very tired in a class, and my eyes felt like weighted 2 tonns, and my body start slacking, as in the muscle start relaxing. This makes our brain misinterprete them and thought we're falling from some places, thus send signal to our muscle to charge them back. That's why you'll wake up with some voluntary muscle movement!

This may also cause by our own dream, and letsay you dreamt that you were in an action movie, fighting with some monsters or what, and the monster push you down a cliff, this will somehow, make the brain feels like having the "falling sensation".

It also happened to those who have hard time to sleep, or always sleep late. Like me.. I'm  a very hard sleeper, i can stay up to 24 hours just browsing forum alone. And when i sleep, normally i'll get this hypnic jerk. Taking nap after class also cause me to have a lot of jerks..

There's no harm for this to happen, just that if you jerk too much until you accidentally kick people or kung-fu with them, you maybe need to warn them everytime you sleep, lol. And the statistics said, almost 80% of people experienced this! I'm not alone! Yeah!