Placeholder Image

Subtitles section Play video

  • have you ever been drifting off to sleep in your bed all quiet at night and

  • suddenly feels like you're falling in your whole body twitches what is that

  • well that's a jerk, a hypnic jerk to be precise, a hypnic jerk sometimes called a sleep start is

  • the scientific term for what happens when you jump in your sleep there the

  • involuntary muscle twitches that happened in your arms legs or even your

  • entire body as you drift off to dreamland, most people get them roughly

  • 70% of the population jumps in their sleep, but why do they happen

  • there are two main theories based on neural science and evolution most common

  • explanation is that as you fall asleep there are two different systems your

  • brain that are basically battling each other. System number one, a network of

  • nerve cells called the reticular activating system is just below your

  • cerebral cortex the big wrinkly part of your brain. when this system is in full

  • force you feel alert, it essentially helps keep you awake. system number two

  • call the ventrolateral preoptic nucleus or VLP0 for short is located near the

  • optic nerve and influences your sleep cycle, the VLP0 sometimes referred

  • to as the sleeps switch, as you fall asleep each night or during nap time

  • the VLP0 system begins to take control from the reticular activating

  • system during this hand off from one system to another the alert part of your

  • brain can still sometimes stimulate your muscles causing twitches, these hypnic jerks are

  • last-ditch attempts by the reticular activating system to maintain control of

  • your body as you more or less choose to sleep, system number one usually

  • seized control the system number two the VLP0 and the hypnic jerks eventually

  • stopped, so these jerks are thought to be the result of a sleeping waking war

  • happening in your body each time you try to get some shut-eye, another less common

  • theory for what causes hypnic jerks involve our primate ancestors. some scientists think

  • that the ancient primate brain associated relaxation or the beginning

  • stages of sleep with falling out of a tree, hypnic jerks were a way of waking the

  • primate up quickly so they could take action and possibly break their fall.

  • so these muscular twitches might have stayed with us as we evolved over the years.

  • whatever causes hypnic jerks they're nothing to worry about according

  • to most experts but if you don't love getting jolted awake feeling like you're

  • plummeting near-death there are some steps you can take to limit how many

  • sleep start to experience things like high caffeine consumption, working out in the evening hours,

  • high stress levels and lack of sleep can cause more frequent

  • and more intense hypnic jerks, so cutting back on the coffee, getting your workout

  • done in the morning and managing your stress levels and sleeping patterns

  • might result in fewer hypnic jerks, but like I said they're not dangerous

  • so if they don't bother you, no need to ditch your afternoon latte, there're bigger jerks

  • out there to battle after all. Thanks to all of our patrons on patreon for not being jerks

  • you keep these answers coming you'd like to submit a question to be

  • answered or get some videos a few days before everyone else, just go to

  • patreon.com/scishow and don't forget to go to youtube.com/scishow

  • and subscribes.

have you ever been drifting off to sleep in your bed all quiet at night and

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B2 US sleep system primate jerk brain ditch

Why Do We Jump in Our Sleep?

  • 13342 861
    Joseph Yap posted on 2016/07/07
Video vocabulary