Drained and exhausted, you are finally in bed sinking into what will be a deep sleep, when your body starts ‘falling’ and it suddenly jerks to stop that ‘fall’. You will of course wake up immediately and wonder where it came from.

And no matter how many times happens, you never get used to it, it never feels less abrupt, and it never gets any better. The falling sensation can even be terrifying, which ends with an involuntary, sudden, and shocking jump.

If this has happened to you at least once, you are not alone. In fact, up to 70% of people experience this phenomenon, also known as hypnic jerks (or sleep starts). Nobody really knows what causes these sudden jerks for sure.

Although a solid explanation for how and why hypnic jerks happen hasn’t been offered, there are two theories that suggest some reasons for this. One states that the hypnic jerks happen as a result of the natural downshifting of the nervous system as you’re falling asleep.

s you finally sink into bed, exhausted and ready for a deep sleep, you may have experienced the sudden, jarring sensation of ‘falling,’ only to be jolted awake by an involuntary body jerk. This startling phenomenon, known as hypnic jerks or sleep starts, is surprisingly common, affecting up to 70% of people at some point in their lives.

What Are Hypnic Jerks?

Hypnic jerks are involuntary muscle spasms that occur just as you are transitioning from wakefulness to sleep. These sudden movements are typically accompanied by a feeling of falling, which can be quite alarming. Despite being a common experience, the exact cause of hypnic jerks remains a mystery.

Theories Behind Hypnic Jerks

While there is no definitive explanation for why hypnic jerks happen, there are two prevailing theories:

1. Nervous System Downshifting: One theory suggests that hypnic jerks occur as a result of the natural downshifting of the nervous system as you drift off to sleep. As your body relaxes and your muscles begin to loosen, your brain may misinterpret these signals as a sign of falling, prompting a sudden muscle contraction to ‘catch’ yourself.

2. Evolutionary Reflex: Another theory posits that hypnic jerks are an evolutionary reflex. In our ancestral past, a sudden muscle spasm might have helped prevent falling out of trees or other precarious sleeping positions. While we no longer sleep in such environments, this reflex might still be hardwired into our nervous system.

The Experience of Hypnic Jerks

For those who experience hypnic jerks, the sensation can be quite unsettling. The abruptness of the jerk often leaves individuals wide awake and wondering what just happened. Despite being harmless, the experience can be unnerving, especially if it happens frequently.

Managing Hypnic Jerks

While there is no surefire way to prevent hypnic jerks, there are some steps you can take to minimize their occurrence:

• Reduce Stress: High levels of stress and anxiety can exacerbate hypnic jerks. Engaging in relaxation techniques such as deep breathing, meditation, or gentle stretching before bed can help.

• Maintain a Regular Sleep Schedule: Keeping a consistent sleep routine can promote better sleep quality and reduce the likelihood of hypnic jerks.

• Limit Stimulants: Avoid consuming caffeine or other stimulants close to bedtime, as these can interfere with your ability to relax and fall asleep.