Have you ever woken up to a falling sensation and a strong muscle twitch as you are simply lying in bed? This phenomenon is known as hypnagogic myoclonic twitch or “Hypnic Jerk,” and studies have shown that roughly 70% of people have experienced it. There is no definitive answer on why this happens, but most scientists have agreed on the following explanation. When you are falling asleep your muscles become very relaxed and enter what is essentially a state of temporary paralysis. While your body is making this transition the brain can misinterpret the sudden relaxation of the muscles and instead think that you are falling. Instincts kick in and send signals to your muscles to jerk you upright which leads to a rude awakening. Studies have found that “Hypnic Jerks” occur more frequently with people who suffer from sleep anxiety, fatigue and discomfort because the brain is more easily confused. Either way, it is a normal part of the sleep process and poses no real danger.
From the Upcoming ueue, submitted by Snappy.
Something weird about the eyebrow image, though. If that's a left eye, doesn't it look like the hairs are growing the wrong way?
I know why we yawn, but why is it when we see someone else yawn, or hear it, or even the mention of the word yawn, gets people to yawn.
@DaveL: the 'small world' ride at DWorld broke down when I was on it in 1989...for 15 long minutes we heard that song over and over and over.
Godammit! That happens to me so often! Thanks for the heads up.