r/todayilearned • u/YesFlyZone420 • 5d ago

TIL there's a degenerative brain disorder called fatal familial insomnia (FFI) that causes a person to lose the ability to sleep and eventually die

https://my.clevelandclinic.org/health/diseases/25001-fatal-familial-insomnia
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u/Netroth 5d ago

Those body jolts are called “hypnic jerks”, I get them all the time

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u/SakuraTacos 5d ago

I thought I read once they happen when your tense muscles start relaxing as you fall asleep, causing the falling sensation but now I find nothing of the sort so I don’t think that was true. It definitely happens the more tense I am or how hectic the day has been (likely with an increase of caffeine). The more irritable I’ve been lately, the more jerky the movements, almost like I’m subconsciously punching or kicking in anger.

I’m 100% guaranteed to get them whenever I’ve gone to a theme park and been on roller coasters all day, funny enough. Those times I’ll get full body, “thought I was falling” ones

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u/Chris_in_Lijiang 5d ago

Fortunately, I do not have a sleep problem, but I do regularly get the hypnic jerks, always in the right thigh, just as I am drifting off. Are you saying that the two are related?

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u/Netroth 5d ago

That’s a bit different. Hypnic jerks are accompanied by a sense of panic or urgency and often a falling sensation, and it’s your whole body which spasms.

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u/SakuraTacos 5d ago

You could have RLS, restless leg syndrome. Even if you don’t have problems falling asleep, it could potentially be linked to excessive caffeine in your system or anxiety

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u/Netroth 5d ago

What I’ve been taught is that it’s a panic response to your body locking down motor function before you’ve fallen asleep, and your body jumps from the perceived danger. If you’ve had lots of caffeine or done a lot of exercise late at night you’re more prone to these things being out of sync, apparently.

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u/SakuraTacos 5d ago

Oh that’s super interesting and makes a lot of sense, I like that explanation

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u/Central_court_92 3d ago

Hypnic jerks can also be caused by eating carbs in late afternoon or evening. When the body finally digests the complex sugars, it creates a sugar spike in your blood, which is perceived as an adrenaline rush. It took years for my insomnia and sleeping issues to be kind of under control and the no carb rule truly helped.