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.