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Why Do We Get Pins and Needles? · So That's Why

0:04
Jen Oliver: Welcome to the, so That's Why Podcast where we unpack the
0:07
science behind everyday questions.
0:09
I'm Jen.
0:10
Chris Smith: I'm Chris.
0:11
Matt Edmundson: And I'm Matt.
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Jen Oliver: Okay, so today's question is something that every single person
0:16
listening will be able to relate to.
0:19
Why do we get pins and needles?
0:22
Matt Edmundson: Good question.
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Uh, we all know that sensation, I dunno if you like me, where your
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foot completely stops working.
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And you're just sat there hoping no one gets to see you try and walk,
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uh, in the next 30 seconds, right?
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Chris Smith: And that, uh, foot won't work.
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Situation is the perfect illustration because that distinctive buzz doesn't
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happen when something goes wrong.
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It's happening when things are actually being corrected,
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Jen Oliver: Which goes against actually what we've all thought.
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But by the end of this episode, you'll understand exactly what's happening at an
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nerve level, why getting pins and needles feels the way it does, and crucially
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why they are worth paying attention to rather than just shaking them off.
1:02
Matt Edmundson: Yeah, and also why your arm can go completely
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dead from sleeping on it.
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But then be entirely fine.
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I dunno if you found this within just a few minutes, which always seems like
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a disproportionately quick recovery for something that felt quite dramatic.
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I wish the common cold was, uh, as fast to recover.
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Jen Oliver: Yeah, imagine.
1:22
Chris Smith: I know.
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That'd be good.
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But yeah, the, the speed of recovery, um, is actually one of the most telling
1:27
things about what's going on, and it's a clue that we'll come back to
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once we've unpacked the mechanism.
1:33
Jen Oliver: So how do they actually start?
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It's got a fancy name.
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As do a lot of things paraesthesia, which is an umbrella term for
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any abnormal skin sensation without an obvious external cause.
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But the everyday kind of pins and needles we get from being in certain
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positions is really a circulation story as much as it is a nerve story.
1:55
Matt Edmundson: That's quite interesting, isn't it?
1:56
I, I, I'd always thought this was a nerve thing.
1:59
Mm. Um, so the circulation angle.
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Uh, it's gonna help me reframe it, I guess.
2:04
Chris Smith: Yeah.
2:04
And they are genuinely, um, inseparable.
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So nerves are extraordinarily demanding structures and they rely
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on a continuous, uninterrupted blood flow to function properly.
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So the everyday positional kind of pins and needles comes down.
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Two things happening simultaneously.
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We've got mechanical compression of a nerve and a reduction in its blood supply.
2:26
Jen Oliver: Exactly.
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So they basically make things worse for each other.
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So the blood vessels that feed the nerve run right alongside it.
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So when you squeeze the nerve, you're actually pinching its
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fuel line at the same time.
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Matt Edmundson: So a nerve under pressure then isn't just physically
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squashed, it's also being cut off from what it needs to function.
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Chris Smith: That's exactly it.
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And a nerve being deprived doesn't simply go quiet.
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It starts sending these kind of chaotic, unpredictable signals
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rather than the orderly ones that your brain is used to receiving.
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Jen Oliver: And that chaotic firing is what the brain interprets as
3:01
something strange and unfamiliar.
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It can't make sense of the signal.
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So rather than recognizing it as an nerve under pressure, it
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registers, uh, registers it as something that needs attention.
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Matt Edmundson: Right.
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So when your leg falls asleep, then it's not actually asleep.
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It's not actually silent.
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It's more like a radio that's kind of picked up interference
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instead of the actual station.
3:24
Chris Smith: Yeah, that interference analogy is a good one.
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In fact, we should call you captain analogy.
3:27
Sure,
3:27
Matt Edmundson: yeah, yeah, yeah.
3:28
Chris Smith: If I'm captain, kind of sensible or Captain MythBuster
3:31
Matt Edmundson: MythBuster,
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Jen Oliver: I,
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I still need one.
3:33
I still need a title.
3:34
Matt Edmundson: Madam MythBuster, wasn't it?
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I can't
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Jen Oliver: remember.
3:36
Yeah, I wasn't keyed on
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Matt Edmundson: that.
3:37
Oh, yeah.
3:37
We need a better one.
3:39
Chris Smith: Um, so I've, I've lost my train.
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We, we'll talk about Oh yeah.
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Your analogy of, um, interference.
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And it is a good one because, um, what determines the specific character of
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that buzz that you get comes down to which nerve fibers are affected and
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in what order, because not all fibers respond to compression the same.
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Jen Oliver: So to add to that, so the big myelinated ones, they're
4:02
called the AB to fibers and they handle regular light touches.
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They're the most sensitive to being squeeze because they need the most energy.
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So they're the first to shut down essentially when the blood flow drops.
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Matt Edmundson: So the fibers whose entire job is to tell your brain
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everything is fine, or the first ones to check out under pressure.
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So is this a bit of a design flaw?
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Chris Smith: Well, yeah, I think, I think it's a fair point.
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And when, um, when those large fibers go offline, the brain stops receiving
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the usual reassuring touch signals and in the absence of that normal
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input, its interpretation of what's happening to that limb shifts entirely.
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Jen Oliver: So you then left with the smaller fibers, the A delta and the C
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fibers that carry pain and temperature signals, and they're more resilient,
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so they keep firing even when the larger fibers have already dropped out.
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Matt Edmundson: Yeah, so your brain is getting the something run signals.
5:00
Without the, actually it's fine signals to balance them out.
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It's like the alarm is going off, uh, without the all clear.
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Chris Smith: Yep.
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Captain analogy.
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Thank you very much.
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But yeah, that alarm without the all clear framing explains why there's kind of often
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a distinct sequence of the experience.
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So many people notice the area goes numb first before that tingling begins.
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And that numbness is the.
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A B to fibers that gem mentioned going quiet.
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The tingling that follows is what happens when those smaller fibers
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are left broadcasting on their own.
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Jen Oliver: And that's a really, it's a really useful distinction 'cause
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many people assume that the numbness and tingling are the same thing, but
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that actually two stages of the same process just happening in sequence.
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Matt Edmundson: Yeah.
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So you go through the numbness on the way in and then the tingling on the
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way back out and those two feelings.
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Are basically the backends of the whole event, right?
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Mm-hmm.
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Chris Smith: Exactly right.
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And, and here's the find that I find genuinely fascinating.
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Okay?
5:59
Make of that what you will geek the tingling itself,
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Matt Edmundson: captain geek,
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Chris Smith: the tingling doesn't happen while the nerve is compressed.
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It happens when the pressure is released.
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And the blood flow is rushing back in,
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Jen Oliver: and that's the key part.
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As the circulation returns, the NA near fibers, they start coming back
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online, but it's not all at once and it's not in a coordinated way.
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So different fibers recover at different speeds, which causes them to
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fire chaotically as they reactivate.
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Matt Edmundson: So the pins and needles are not, then the
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injury is what I'm hearing.
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They're the recovery.
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So you feel the worst of it when you are actually getting better.
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Which kind of reframes the experience.
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Chris Smith: Yeah, absolutely.
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And picking up on that recovery idea, the reason the tingling seems to travel
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that kind of crawling feeling, moving up your foot or along your arm is because
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it's following the actual nerve path as sections progressively come back online
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Jen Oliver: and different fibers also have different recovery thresholds,
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which is why the sensation shifts from like a burning to a buzzing to something
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more normal over the course of a few minutes, it's staged and it's sequential.
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Matt Edmundson: So your nervous system is doing a staged restart section by section,
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and those uncomfortable feelings are just.
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In my terminology, the loading screen.
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Chris Smith: Absolutely.
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And it explains that kind of quick, I think you said few minute or two minute
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recovery that you, Matt mentioned right at the top, the nerve was never
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damaged, it was just temporarily offline.
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And once that blood supply is restored, the hardware is
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intact and recovery is rapid.
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Jen Oliver: And that distinction between positional, parathesia and
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nerve damage is key because like a brief compression that resolves cleanly,
7:41
but a prolonged or repeated pressure.
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That can cause structural changes over time.
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Matt Edmundson: Yeah.
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So there's a meaningful difference, isn't there, between sitting awkwardly
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for 20 minutes, which I do do, and then doing the same thing every
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day for years, which I may do.
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Um, and I guess the body can handle the occasional mistake.
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It's that sustained habit that changes things.
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Mm,
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Chris Smith: it is.
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But to look at.
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From another angle, this is all fine unless the cause isn't positional at all.
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So pins and needles can also be one of the first signals of an
8:12
underlying health condition, and it's worth knowing what to look for.
8:15
Jen Oliver: Yeah, so diabetes is probably the most clinically significant cause,
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um, having persistently high blood sugar that damages the small vessels that
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supply peripheral nerves, the same ones that we've been chatting about and that
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eventually causes peripheral neuropathy.
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You know, chronic tingling and numbness, and that usually
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starts in the hands and the feet.
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Matt Edmundson: Yeah.
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So it's the same mechanism, right?
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Nerves not getting enough blood.
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But this time it's chronic rather than temporary.
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Chris Smith: It is.
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And um, the scale of it is striking.
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So research from diabetes uk um, estimates that around 50% of people with diabetes
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develop some degree of peripheral neuropathy, making it one of the most
8:55
common causes of, uh, complications of the condition of diabetes.
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Jen Oliver: And that statistical alone is a good reason to take persistent,
9:02
unprovoked tingling seriously.
9:05
Um, another cause vitamin B12 deficiency.
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Um, is a co a cause that's often underdiagnosed, so B12 that maintains
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the myelin sheath, the protective coating around your nerve fibers that lets
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signals travel quickly and accurately,
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Matt Edmundson: which is particularly relevant for anyone who's on a plant-based
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diet because B12 is entirely, uh, well, almost entirely absent, isn't
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it, from, um, non-animal food sources.
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So it's not a deficiency that's gonna correct itself without
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kind of deliberate action.
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Chris Smith: Exactly.
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It's so important.
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And, um, without adequate B12, that myelin progressively degrades with one
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of the earliest symptoms typically being tingling or numbness in the extremity.
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So the hands and the feet, but it becomes more serious,
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neurological issues can develop.
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Jen Oliver: But what makes B12 tricky is that the body stores a large
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reserve of it, and the depletion happens gradually over months or years.
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So by the time someone's symptoms appear, they may actually be really deficient.
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Matt Edmundson: Yeah, so persistent pins and needles then in your hands could
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be your body's first clear, noticeable signal of a nutritional gap that's been
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quietly building up for a long time, and it's probably worth taking seriously.
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Yeah.
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Chris Smith: Yeah, it really is.
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And that's why regular B12 monitoring for all of us is, uh, so important.
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And it's particularly for those on long-term, um, diabetes
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medications like metformin, which interferes with B12 absorption.
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Jen Oliver: And magnesium.
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That's another one that's probably worth us flagging that directly affects nerve
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signal transmission and low magnesium.
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It makes the nerves more excitable, which produces spontaneous tingling,
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especially again in the hands and feet.
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Matt Edmundson: And magnesium is one of the most consistently under consume
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minerals in our modern day diet, isn't it?
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Mm-hmm.
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So it's another case where the nutritional gap might be showing up as a symptom.
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Um, that seems to be completely unrelated to food.
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Chris Smith: Uh, it's a really good point.
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And um, carpal tunnel syndrome is another very common cause, and it follows the same
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compression logic we've already laid out.
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So in this case, the median nerve gets compressed as it passes
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through a narrow channel in the wrist producing this kind of.
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Tingling, uh, specifically in the thumb, the index finger and the middle fingers.
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Jen Oliver: But what's worth adding to that is that carpal tunnel, it isn't just
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a risk problem 'cause it's a nerve pathway problem, and the median nerve that you
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mentioned that runs from the neck all the way to the fingertips, and compression
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anywhere along that root can contribute to symptoms that you feel in your hand,
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Matt Edmundson: which explains why it's, I guess, so widespread now.
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Right?
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Um, if you're at a keyboard, six to eight hours a day, or 10 to 12
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hours a day, depending on your job.
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Um, if you've got your wrist sort of bent, slightly out position, the nerve is
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sort of under this low level compression, isn't it, for most of your working life.
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And I, I figure it's eventually gonna stop tolerating that.
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Mm-hmm.
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Chris Smith: And with this whole topic of pins and needles, there's one more cause
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that genuinely catches people off guard.
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And that's anxiety.
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So when we're anxious, we tend to over breathe often, quite subtly,
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you know, without even noticing.
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But this lowers the CO2 levels in our blood.
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Jen Oliver: Yeah.
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And that CO2 drop, it's got direct physiological consequence, so it
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changes the blood pH, it lowers blood calcium, and that increases
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the peripheral nerve excitability.
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So that means the nerves start firing more spontaneously, producing
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tingling, particularly in the hands and around your mouth.
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Matt Edmundson: Mm-hmm.
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So the tingling you get during an anxious moment that isn't
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imagined, it's a real measurable.
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Um, physiological response to a breathing change, right?
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Jen Oliver: Mm.
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Chris Smith: Yeah.
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And, and the evidence for it is, um, surprisingly direct.
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So studies using controlled hyperventilation.
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Can reliably reproduce pins and needles in healthy subject within two to three
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minutes, which shows exactly how quickly CO2 changes affect that nerve function.
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Jen Oliver: But the good news is that, you know, slow control breathing
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during an anxious episode, it doesn't just calm you psychologically, it
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actively corrects that CO2 imbalance.
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So that's triggering the nerves, which is why the tingling fades as you
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breathe more slowly and gain control.
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Matt Edmundson: Yeah, so there's a specific physiological loop
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at play here, isn't there?
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That we can see.
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You've got anxiety, which triggers shallow breathing.
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Mm-hmm.
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Um, which then drops the CO2 levels, which then makes.
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Um, nerves, fire spontaneously, which feels alarming, which
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can then deepen the anxiety.
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Mm-hmm.
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Uh, and knowing what's happening I think is a good way to help break that loop.
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Jen Oliver: Yeah, yeah,
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Chris Smith: totally.
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And, um, building on that, so brief pins and needles that go away as
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soon as you move are totally normal.
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So the good news is that's exactly what most people experience rather than
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something kind of more serious behind it.
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Matt Edmundson: Yeah.
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Fascinating.
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I mean, the practical rule I'm taking from all of this.
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If change in position fixes it, it's almost certainly mechanical.
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Mm-hmm.
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If movement makes no difference at all, um, that's the signal
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probably to go get it looked at.
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Jen Oliver: Exactly.
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And the patterns worth flagging to a doctor are persistent,
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tingling in the same location without a positional explanation.
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You know, tingling that comes alongside muscle weakness or symptoms that are
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consistently worse at night when you haven't even been in an unusual position.
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Chris Smith: Yeah, and beyond those, I think any sudden onset
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of numbness or tingling in.
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You know, one side of the body.
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Yeah.
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Especially alongside the, um, like facial drooping, slurred speech or arm weakness
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that needs emergency attention because it can indicate a stroke or a TIA.
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Mm-hmm.
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Matt Edmundson: Yeah.
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And that presentation is clearly different right from gradual,
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uh, from the gradual bilateral.
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I've been sitting on the floor in a weird position way too long.
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Mm. Um, it's sudden it's one-sided and accompanied by other things that feel.
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Unmistakably wrong.
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Jen Oliver: Yeah.
15:06
So as Matt says, the vast majority of pins and needles is your body doing
15:10
exactly what it should be, but it's a sensation worth staying curious about
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rather than always dismissing it.
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Chris Smith: Yep, it is.
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And so for everyday positional kind of pins and needles, gentle movement
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is the most effective response because it encourages that blood flow.
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It speeds up that nerve recovery process that we described earlier.
15:30
Jen Oliver: So here's a fun fact for you.
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There is
15:33
Matt Edmundson: F I've figured out your name.
15:34
Jen Oliver: Go on.
15:35
Matt Edmundson: Fun fact, Jenny.
15:37
Jen Oliver: So you two get capped in something and I get you
15:39
Matt Edmundson: can be captain in.
15:40
Fun fact.
15:40
Fun fact.
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Jen Oliver: Okay.
15:42
Okay.
15:43
I thought I was just gonna get fun.
15:44
Fact, Jenny.
15:45
Okay, so yeah, so here's a fun fact.
15:47
There is no evident.
15:49
For the vigorous shaking is more effective than gentle movement
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to get rid of pins and needles.
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So the nerve just needs circulation restored and a bit of time to resequence
16:00
its firing, which happens naturally.
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Matt Edmundson: Well, thank you, uh, captain from fact because I am the
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person that violently flex my hands trying to get, you know, like I'm
16:10
trying to launch it off my wrist.
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Uh, and I figure I'm not the only one that's, uh, that's done that.
16:15
Jen Oliver: No, no, no,
16:15
Chris Smith: Yeah, there's genuinely no need for the kind of vigorous action.
16:18
Um, gentle is enough, but for recurrent carpal tunnel symptoms,
16:23
specifically wrist splints worn at night have solid clinical evidence.
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They prevent the risk from flexing during sleep, which is when
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compression tends to be at its worst.
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Jen Oliver: And for the anxiety related kind, slow diaphragmatic breathing is
16:38
probably the most direct intervention.
16:40
So you are actively restoring CO2 levels and reducing the nerve
16:45
excitability, not just managing how you feel about the situation.
16:50
Matt Edmundson: So the box breathing that gets recommended for anxiety is
16:53
a direct physiological reason why it works specifically for the tingling.
16:58
Jen Oliver: Mm-hmm.
16:59
Chris Smith: Yeah.
16:59
And for a lot of people.
17:00
If you think of kind of office workers, the most useful long-term habit is
17:04
actually about posture and screen setup.
17:06
So keeping your wrists in a neutral position during keyboard work.
17:10
Taking regular breaks from sustained positions that removes
17:14
the low level compression that accumulates across that working day.
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Jen Oliver: Well, if you get chronic or recurring pins and needles, try and focus
17:22
on root causes like posture, nutrients, blood sugar, rather than quick fixes.
17:28
Matt Edmundson: Yeah, so the long term answer isn't what you do when it happens.
17:34
It's the conditions you're creating day in, day out that determine how
17:38
often it shows up in the first place.
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Jen Oliver: And that connects back to a lot of ground we've covered before,
17:44
like B12, vitamin D, Omega-3, magnesium.
17:48
These all affect neurological function in different ways, and pins and
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needles is just another place where those gaps surface as physical signals
17:56
before anything more serious develops.
17:59
Chris Smith: Yeah, that's a really important thread and blood flow.
18:02
Quality runs through all of it.
18:04
So whether it's cardiovascular health, uh, brain function, or
18:08
peripheral nerve health, the quality of circulation fundamentally shapes
18:12
how the whole system performs.
18:15
Matt Edmundson: Yeah, and it also ties back to the brain fog episode where nerves
18:19
under sustained stress and nutrients aren't reaching where they need to go.
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The body uses these sort of sensations like pins and needles to flag something.
18:28
It can't communicate in any other way.
18:30
Jen Oliver: And I keep coming right back to what Chris said at the start,
18:33
that the pins and needles themselves are the recovery, not the damage.
18:37
So the uncomfortable sensation is actually proof that your
18:40
nervous system is doing its job.
18:42
Chris Smith: Yeah, and it's a good reminder that the body's warning
18:45
systems, uh, signals are often the same as its repair signals.
18:49
So the discomfort and the correction are the same event happening at the same time.
18:54
Matt Edmundson: Your nervous system, your nervous system, staging a full.
18:59
Uh, protest turns out to be working exactly as intended,
19:03
which makes it considerably easier to live with that knowledge.
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Jen Oliver: So that's why the next time that familiar buzz starts
19:11
working it's way up your foot, you'll know exactly what's happening.
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That's not a problem.
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That's the recovery already underway.
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Yeah.
19:19
Matt Edmundson: Your nervous system is doing a full-time reboot in real time.
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Jen Oliver: So that's it for this week.
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Hit subscribe and drop as a comment with whatever question
19:29
you'd like us to explore next.
19:31
Thanks for geeking out with us, but for now, that's it from me.
19:35
Matt Edmundson: That's it from me.
19:36
Chris Smith: And that's it from me.
19:37
Jen Oliver: Bye for now.