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Why do we get pins and needles? | Strange science for kids · The Curious Kidcast | Fun Facts and Curious Questions

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  You're sitting on the floor minding your own business, being
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  a completely normal human person.
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  And then you stand up and your foot is just completely quit.
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  It's given up. It's gone on holiday without
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  telling you. It's fizzing, It's tingling.
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  It feels like hundreds of tiny ants are throwing a party on
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  your leg. And you try to walk and you look
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  like a baby giraffe who's just been told some very surprising
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  news. Today on the Curious Kid cast,
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  we're answering one of the most asked questions we've ever had.
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  Why do we get pins and needles? What is actually going on inside
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  your body when it happens? And why does shaking your leg
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  make it stop? The answers involve electricity,
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  lightning speed and 86 billion nerve cells.
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  Yes, really. This is the Curious Kid cast.
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  Curious kid cast? Here we go.
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  Questions popping minds will blow.
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  Hello and welcome to the Curious Kid cast, the show where we take
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  your biggest, brainiest, most baffling questions and actually
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  answer them properly. Unlike your uncle who just says
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  that's just how it is and goes back to his sandwich.
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  I'm Charlie and today we are talking about pins and needles
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  and honestly the science behind it is so cool that your foot
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  abandoning you might actually become your favorite thing
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  that's ever happened to you. Today's question comes from
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  Theo, who is 9 years old and lives in Cardiff, Wales.
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  Theo was sitting through what he described as the longest school
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  assembly in recorded human history, cross legged on a hard
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  floor while someone talked for what felt like several decades
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  about the importance of tidying up the cloakroom.
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  When he finally stood up to leave, his legs went completely
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  haywire. He wobbled.
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  He nearly fell over. His teacher asked if he was all
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  right, and he didn't know how to explain it, so he sent his
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  question to us instead. Brilliant thinking.
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  Theo, we've absolutely got you right.
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  To understand pins and needles, we first need to talk about your
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  nervous system. And honestly, once you hear
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  this, you're going to realize that you are basically a
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  walking, talking electrical supercomputer.
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  Your nervous system is like the Internet, but it lives inside
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  your body, which is much more impressive and also much harder
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  to turn off and on again. Your brain is the main computer,
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  the big boss, the one running everything, and it sends
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  millions of messages every single second through tiny
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  cables called nerves, all the way out to every part of your
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  body. Your toes, your nose, your
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  earlobes, the weird bits at the back of your knee, all of it
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  connected. And those messages aren't sent
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  by tiny little messengers running around inside you, which
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  would be chaotic but also kind of brilliant.
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  They're sent by electricity. Actual tiny electrical signals,
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  like teeny tiny bolts of lightning shooting through your
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  body up to 120 meters per second.
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  That is faster than a Formula One racing car.
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  You are literally powered by lightning.
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  You're basically a thunderstorm in a jumper.
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  There are two main types of nerves.
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  Sensory nerves carry messages to your brain, telling it what you
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  can feel, whether something's hot, cold, sharp, fluffy or
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  suspiciously sticky. Motor nerves carry messages the
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  other way, from your brain to your muscles, telling them to
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  move. Both of these are involved in
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  that fizzy, weird feeling, and we're about to find out exactly
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  why. So here's what actually happens
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  when you get pins and needles. When you sit in a funny position
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  for a long time, like cross legged on a hard floor listening
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  to a very long speech about the cloakroom, your body weight
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  pushes down on the nerves in your legs.
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  And when a nerve gets squashed, something really important gets
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  cut off. Blood.
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  Your nerves need blood to work. Blood delivers oxygen and a type
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  of sugar called glucose to your nerve cells, giving them the
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  energy to fire off all those electrical signals.
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  But when you're sitting on your leg, you're also squashing the
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  tiny blood vessels that carry that blood to the nerve.
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  Less blood means less oxygen, less fuel, and the nerve starts
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  to really, really struggle. It's like when your tablet gets
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  down to 2% battery and it just starts doing completely unhinged
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  things. Apps crash.
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  The screen flickers. It opens something you didn't
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  ask for. That's basically your nerve
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  right now. Instead of sending nice
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  organized messages to your brain, the nerve starts firing
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  off random, confused, chaotic signals, and your brain receives
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  all of this absolute nonsense and tries to make sense of it.
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  The result is that bizarre tingling, prickling, fizzing
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  sensation. Your brain is essentially saying
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  I'm getting some very strange messages from your foot.
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  I don't know what's going on down there, and frankly I'm a
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  bit concerned. Before the pins and needles
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  starts, your leg might go completely numb first.
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  That's the nerve giving up on sending any signals at all
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  rather than sending confused ones.
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  And that numbness is actually your body being really clever.
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  It's a warning. It's your body saying, oy,
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  something's not right, you need to move, please.
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  And that warning is genuinely important because if you stayed
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  in one position for too long without ever feeling
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  uncomfortable, you could actually damage your nerves and
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  cut off blood supply to your muscles.
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  Pins and needles. Is your body protecting you?
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  Even when you're just trying to survive a very tedious assembly,
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  your body is really doing its best for you now.
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  Why does shaking your leg make it go away?
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  When you move, you take the pressure off the nerve so it's
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  no longer being squashed and movement gets blood flowing
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  again, rushing fresh oxygen and glucose back to those very
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  hungry nerve cells. As the nerve starts recovering,
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  it sends one last burst of confused signals to your brain,
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  and that's why the pins and needles feeling often gets more
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  intense for a few seconds before it fades.
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  It's like a computer rebooting. There's a moment of flickering
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  chaos before everything settles down and acts normal again.
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  Which is exactly how I feel on Monday mornings.
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  You can get pins and needles almost anywhere because you've
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  got nerves absolutely everywhere.
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  Feet and legs are the most common.
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  Hands and arms often go numb if you sleep on them in a weird
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  position. You might have woken up with an
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  arm that feels completely dead and not like your arm at all,
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  and that's the same thing. But here's the one I really
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  love. Have you ever bashed your elbow
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  on a table and felt this massive electric ZAP shooting all the
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  way down into your fingers? People call it the funny bone,
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  which is a terrible name because it isn't a bone and it isn't
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  funny. It's actually a nerve called the
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  ulna nerve, and it runs really close to the surface of your
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  skin, right at the elbow. One tiny knock and it completely
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  loses the plot. That's pins and needles
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  happening instantly and very dramatically.
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  Your body contains about 86 billion nerve cells.
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  If you stretched all of your nerve fibers out in a single
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  line, they'd wrap around the earth 2 1/2 times.
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  Some nerve cells are nearly a metre long.
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  A single cell going from your lower back all the way down to
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  your big toe. You're not just a human, you're
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  essentially 100,000 kilometres of biological electrical wiring
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  squeezed into a person shaped container.
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  That's wild. Pins and needles is also one of
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  those things that every single human who's ever existed has
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  experienced. Ancient Romans got it.
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  Medieval Knights probably got it after kneeling an armor for
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  hours and then had to awkwardly waddle away.
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  Astronauts on the International Space Station have felt it
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  floating around in zero gravity. We're all connected by the
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  shared experience of our own feet going completely rogue on
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  us. Beautiful, really, right?
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  Quiz time. 3 questions and I want your best answers.
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  Question one, how fast are the fastest nerve signals in your
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  body travel? Is it a 10 meters per second, B
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  120 meters per second, or C1 meter per second?
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  Have a think? The answer is B 120 meters per
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  second faster than a Formula One car.
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  You've got racing car speeds inside your body right now and
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  you didn't even know it. Question two, What does your
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  body cut off when a nerve gets squashed?
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  Is it a water, B electricity or C blood?
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  The answer is C blood. No blood means no oxygen and no
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  glucose, and the nerve basically starts sending your brain
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  nonsense, which, to be fair, your brain gets enough of
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  already. Question three.
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  What's the real name of the nerve you hit when you bash your
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  elbow? Is it A the funny bone nerve, B
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  the ulnar nerve, or C the zappy elbow nerve?
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  The answer is B the ulnar nerve. The zappy elbow nerve was not a
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  real option, but honestly it should be.
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  Someone needs to sort that out. And that is it for today's
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  episode of The Curious Kid cast. A huge thank you to Theo from
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  Cardiff for the brilliant question.
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  Next time your foot goes all fizzy and weird, don't panic.
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  Just think about all those 86 billion nerve cells having a
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  little moment and feel genuinely amazed that your body fixed
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  itself in under 2 minutes. If you enjoyed this episode,
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  please share it with a friend, a classmate, or someone who
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  recently had a pins and needles incident and deserves a proper
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  explanation. And if you haven't subscribed
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  yet, please do so. You never miss an episode.
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  If you've got a question you'd like answered on the show, head
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  over to curiouskidcast.com and send it in.
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  Your question could be the next one we explore.
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  Until next time, stay curious.