WHOA… did you know this? :O
But let me give you a brief explanation. These are called hypnogogic jerks and about 50-70% of people do this, although most people don’t even realize it. There are a couple of theories as to why these happen it it goes something like this. The first is that when we fall asleep, two parts of the brain, right behind our eyes start working to reduce the level of serotonin (a feel good chemical that helps us be happy, awake and helps us move our major muscles). These parts of the brain also release a couple chemicals that stop us from moving our muscles including our smaller muscles. For a short period of time, because the smaller muscles are still not affected by these chemicals so we still move a little causing us to twitch.
For a more detailed explanation and to hear the other theories check out the video below. And don’t forget to share this eye-opening video with your friends and family!