I am a little curious about your description of your whole body jerking upward. Can you be more specific in your description?
The reason I ask is years ago I had a few episodes that were never satisfactorily explained to me. They woke me fom a dead sleep and were not while dozing off. They only happened when lying on my back, and I would awaken lurching to a sitting position while exhaling forcefully. That was before I was being treated for OSA, so I kinda thought it may have been the end of an apnea event and that inhaled air that had been blocked from escaping broke free so forcefully my stomach muscles contracted and pulled me upright. My doc at that time said they'd not heard of that with OSA. Come to think of it, I haven't mentioned that to my current sleep doc.
My other thought on my episodes was that my Periodic Limb Movement Disorder (PLMD) contractions of my legs were so forceful my stomach muscles were involved and pulled me suddenly forward forcing the strong exhale.
I may never know what was going on with me, as I am being treated for both my OSA and PLMD and I haven't had an episode for several years. Your episode is probably not the same as mine, but your description caught my attention.
Lack of sleep is the number one factor that causes this to happen. It has been happening to me lately also because I am unable to sleep well due to issues with pain.
They are reffered to as Myoclonic Jerks as ladeechaz pointed out and sometimes I will sit upright from them.
This is a very common thing, and as far as i know it doesn't mean you have a health problem. The not sleeping the night before/all nighter's is problerbly the cause for it (over tiredness). It's all to do with when the body is leaving it's concious state, but is still partly awake, and the jerk you get right before falling to sleep is your body's/brain's response to it, basically waking you back up cos it's confused or because when you're falling to sleep your muscle's relax and also your heartbeat and breathing slow down which trigger's a jerk. I've experienced it a few time's, usually when i'm drifting off to sleep and don't really wanna be when lying on the sofa or something. There's also another extremely common thing people experience right before falling to sleep which is called 'the falling sensation' which i also have had.
What you experience is called Myoclonic Muscle Movements or a Hypnic jerk.
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