Did it hurt when you fell… in your sleep?

Bedroom. Image by Alex Robert via Unsplash

I have a vivid memory from my childhood. To set the scene, my younger brother and I shared a bedroom; his bed beside his blue wall and mine beside pink (quite stereotypical I know but not the centre of my short story). My parents would always read us a story, kiss us both goodnight and turn off our lamp, leaving us alone in the dark room. At the mere age of five, I wasn’t the biggest fan of the dark.

Anyway, I was minding my own business and possibly recalling the extravagant story which we’d heard moments before, when I heard a large thump from the bed beside me. It was as if my brother had fallen from several feet above the bed. I quickly turned on the lamp to check if he was ok, yet he was peacefully sleeping, evidently unaware of the fuss he’d just caused.

Falling onto bed. Image by Darius Bashar via Unsplash

That was my earliest memory of ‘falling in your sleep’, and even I myself have experienced it many times since then.

Scientifically known as a ‘Hypnic Jerk’ or a ‘Sleep Start’, this phenomenon is caused by an involuntary muscle spasm. The muscle spasm occurs during the transition of wakefulness into sleep and is often associated with the feeling of falling. This is no medical disorder and is actually a pretty common occurrence. If you’ve ever been woken by the very realistic sense that you’re falling, you can join the other 70% of the population who have experienced it too.

I know this isn’t a medical breakthrough or a solution to climate change, but I’ve always been interested in knowing if there is any scientific evidence behind cool and weird experiences like this.

No, science doesn’t believe that you’re just dreaming of falling, and your physical body joins in to make it a great 3D experience. Turns out, there are a few different theories for why people think Hypnic Jerks happen, but conclusive evidence is still yet to be published.

A guy falling. Image by Floris Jan-Roelof via Unsplash

One theory suggests that nerves may misfire as we transition from wakefulness into sleep. This means that while our brain is telling our body and muscles to relax, one or two nerves may fire spontaneously. This then leads to activation of the area in which those nerves lie. Creating a jolt, this may explain the reason to why we can feel as if we’re falling.

Some evolutionary scientists believe our bodies still have an ‘ancient primate reflex’. This supposed theory suggests that, in the 21st century, our bodies are still capable of having innate responses to long gone dangers. A long time ago, primates would have been faced with dangers such as predators and falling. Some believe that this hypnic jerk was an alert mechanism to remind the primates of potential threats whilst they dozed off to sleep, like being attacked by lions or falling out of a tree. To me, the connection seems a tad bit far-fetched. We no longer require a hypnic jerk to remind us of threats when falling asleep in our comfortable beds. Maybe evolution deems it important, who knows.

Monkey in tree. Image by Joy Ernst via Unsplash

A final theory which seems most believable to me is that of a reflexive phenomenon. This theory indicates that a hypnic jerk may be a mere reflex to the lengthening of spinal muscles. As we fall asleep, the muscles attached to our spine relax and lengthen. If the muscles lengthen quick enough, this is suggested to stimulate our muscle spindles which creates a stretch reflex. A reflex can lead to our body jolting, creating a sense of falling. This idea is similar to the knee jerk reflex – if gently hit in the right spot underneath the knee, our lower leg will kick out involuntarily. Try it if you don’t believe me!

So, don’t worry if you experience falling in your sleep every night or have never experienced it before. These theories lack scientific evidence but do suggest it’s a natural process of transitioning into sleep. If you really want to avoid them, recommendations of cutting out caffeine and stimulants close to bed time will ensure you get a better nights sleep.

Coffee before bed. Image by Nathan Dumlao via Unsplash

Happy sleeping and falling!

10 Responses to “Did it hurt when you fell… in your sleep?”

  1. Seana Glover says:

    Thanks so much Leo! Exactly it would need to be a common occurrence in primates. Even if so, that does not necessary imply the same for humans!

  2. Leo Featherstone says:

    Hi Seana, this was a great read :). I too am sceptical about the evolutionary relic argument. We would need to observe such a reflex in sleeping primates right?


  3. Seana Glover says:

    Thank you! I thought the images of the men falling were pretty accurate 😂

  4. megany says:

    this post was so interesting to read! i also really liked the images you used; i have definitely experienced this when i’m sleeping

  5. Seana Glover says:

    Thanks so much Jasmine 😃

  6. Seana Glover says:

    Thanks Natasha! Its amazing how many people experience this, I’m glad to provide people with some possible answers 🙂

  7. Jasmine Rhodes says:

    Ohhh so relatable! Great topic choice, Seana 🙂

  8. Natasha Anderson says:

    This was a really interesting post! I’ve had this happen to me so many times so it’s great to read some theories as to why!

  9. Seana Glover says:

    Thanks so much Flora! Yep you must 😉

  10. Flora Norton says:

    Such a good post Seana! I’ve always wondered about this – happens to me all the time – I guess i must have a lot of monkey in me lol