get the same feeling too, and actually last night also- I also suffer from PVC/extrasystoles, but also anxiety- And seams many with anxiety get this.
You say it feels like your heart stops and you get a jolt.
http://www.medhelp.org/posts/Anxiety/Adrenaline-rush-when-trying-to-fall-asleep/show/415706
look here.
But with my anxiety this bugs me as well when it happens.
Do you have anxiety about your heart?
Ill share my situation and you can see if it makes sense.
I worry allot about my heart for the reason that I have a hard time believing the extra-systoles are not threatening.
Mostly when they come during workouts or similar.
So i think this "rush" is a part of that fear.
Ive read that when you sleep your heart rate might fall beyond the "resting" heart rate you measure when waking up.
A part of the process where the body doesnt need to pump that much oxygen to the rest of the body.
Also i have had one night where this happened about 10 times in a row with about 3-5 minutes in between, and logical question then would be : did my heart stop 10 times?
Scary thought, but i think no. Why would it stop 10 times and recover 10 times?
If so its a great ability.
Also, some places it has been linked to Sleep paralysis. (which mostly is waking up/falling asleep paralyses. ) - But ive read once that one of the side effects might be exactly this.
and i do have sleep paralysis from time to time.
Now, since im of course still scared ******** about the heart and all due to anxiety, im not gonna say "there is no need to see the doctor".
I have no idea how your medical history looks like. So go see him if needed. If not just to see if he might be able to give you a more "medical" answer than i could ever get from my doctor.
But looking at the thread/Link i posted youll see where are many with this issue.
Also, i consider myself you still. To young to have gotten a serious heart condition.
Im 24 and had extra systoles since i was about 18.
Ive had sleep paralysis happen from time to time since that age too.
And this adrenalin rush awakening ive had many times too the last 2 years or so.
so yeah.- All that i have written here is stuff i try and keep myself calm with and might be of use for you.
And if someone would be able to go back in this section and look at my biggest issue id be happy.
But hope for the best for you.
Also about sleep paralysis, if you want to know more there, i read allot about it. Not making me an expert, but here where im from people are oblivious to that state. So i know a thing or two both from books and from experience.
And the reason i pull out sleep paralysis is this.
(cut from wiki)
****When it occurs upon falling asleep, the person remains aware while the body shuts down for REM sleep, and it is called hypnagogic or predormital sleep paralysis.****
So your actually awake while you are falling asleep in one sense. . . . That should be scare and might likely send a rush of fear through your body.
Also the word hypnagogic *** is the transitional state between wakefulness and sleep***
***When it occurs upon awakening, the person becomes aware before the REM cycle is complete, and it is called hypnopompic or postdormita****
So its not all about being paralyses and seeing weird stuff as many think.
It all happens because of a "harmless" anomaly in the brain, that makes it shut down for sleep while you are still aware.
So instead of feeling tired. . .. Closing your eyes... then waking up in the morning. . . .
Your experiencing a part of what comes between closing your eyes and waking up.
Your experiencing how the body sleeps, which most people are unaware off.
So yeah i leave you with that.
Of course again, i am by no means a doctor or expert, but just seams that world wide "and here mostly" no one gives a damn about learning what sleep paralysis is.
when i asked my doc about the same situation you asked about, his answer was this :" oh its just cause you feel like your falling then you wake up".
And you then hearing that answer would say :" yeah right! its nothing like that. . . i havent even fallen asleep yet. "
So yeah let me know what you think. If not for my curiosity. But also to strengthen myself against my own anxiety.
(also i refereed you as one having anxiety. While you might not. - Otherwise make sure to look at your feelings too- Mostly to catch the anxiety if there is one as quick as possible. )
Mine was first discovered about 4 years after it appeared, so doesnt make it easier to battle now-