Have you ever been comfortably drifting off to sleep only to be woken up by sudden jolt like you’ve missed a step on your staircase?
If so, you’re not alone, in fact the phenomenon is so common that there’s even a word for it – the hypnic jerk.
Sounds a bit like a dance move, but it can actually be quite frustrating.
Scientists agree that jerking and twitching while sleeping is completely normal and nothing to worry about.
Medical director Dr.William Kohler, of the Florida Sleep Institute, claims that as many as 70% of people experience hypnic jerks.
This was backed up byJames K. Walsh, executive director and senior scientist at St. Luke’s Sleep Medicine and Research Center.
He explained to NBC News : “A hypnic jerk or sleep starts are a perfectly normal occurrence that is almost universal.
“It involves a total body experience where your muscle contracts therefore your limbs jerk or your body twitches.
“They generally occur during the transition between wakefulness and sleep.”
Basically, when the body goes to sleep it moved though different stages.
Stage one, the body behind to fall asleep, then stage two and three occur until the body moves into rapid eye movement (REM) sleep.
This final stage is when dreams occur.
The cycle repeats around four or five times overnight while you enjoy your kip.
A hypnic jerk, also known as a hypnagogic jerk, occurs between stage one sleep and being awake.
The event lasts between half a second or less and isn’t considered dangerous – this means not too much research has been done on the occurrence.
Rafael Pelayo, a sleep specialist at the Stanford Sleep Medicine Center, spoke to Mic about hypnic jerks and claims that usually you’ll notice them due to moving your arms or legs.
However, he noted that if you dose off while sitting upright you might snap your head back.
The sudden jerks are a sign that you’re sleep deprived but are forcing your body to remain awake when it doesn’t want to be.
When the movements happen it’s a sign that the body will transition straight from stage one sleep into REM when you nod off.
So, you might have more vivid dreams.
Raphael added that when we make ourselves stay awake despite being sleep deprived parts of our nervous system go to sleep.
Your control over muscle movements when asleep is very different to when awake and so this is why your limbs twitch.
So, don’t worry if you frequently feel jolts when dozing off.
It’s not dangerous… unless you kick your partner by accident.