Dozing off for a few seconds - waking up by having a body spazm

[benzilla04]

I was watching a movie late at night (as you do) and I dozzed off to be woken up a few seconds later by a body spazm. (Like the ones you get from a nightmare) and I done this twice in a row. It kept happening alot a few weeks ago, almost every or every other night. now it's just here and there Why does this happen?

[isthisit]

It's very common, like the feeling of falling that wakes you up with a start. They are called Hypnic jerks, they occur during hypnogogia, - thought to be caused by irregular sleep patterns, comsumption of caffiene or alchohol before bed, etc