Why do my arms fall asleep at night and wake me up? (side sleep) 2023 Update

wedge pillow

Why do your arms go numb?

Does this sound familiar?

You wake up from a good night’s rest (or perhaps not so good…). And then you discover that your arm has decided not to wake up with you. It might even feel like it belongs to someone else. Or perhaps this funny lack of feeling has kept waking you up at night. Not a very pleasant experience. Especially when the sandman has to return multiple times.

So what’s going on here?Why are arms falling asleep at night waking me up?

Simply put, your arm went numb. Which is often followed by paresthesia. Ah! Para-what? Call the doctor! Alert the neighbours! Call the lawyer to fix your will! Wait, wait, hold your horses, no need to panic just yet. Paresthesia is the fancy medical word used by those fellows in the white lab coats. It describes that pins and needles sensation you feel as your arm comes back to life. Soon to be followed by you trying to get back to your life.

After all this drama, the questions might start coming


Why does my arm go numb while I am sleeping on my side??

Why do I feel pins and needles?

Why is it that when my arms falls asleep at night it keeps waking me up???

And of course, followed by the million dollar question:

How can I stop this from happening?????

So lets get down to it.

We’ll start with the big why

Why does my arm go numb?

Let’s begin with the general principal. First, imagine yourself on a calm, cool evening, getting all set to water your blossoming petunias. You get out your hose, pull it up to your garden, turn on the faucet, aim your nozzle, get it all set to spray, and then…. Nothing comes out. A muffled giggle soon gives it away. Your local neighborhood Denis the Menace is stepping on the hose. Completely blocking the water flow. Sigh….

Now let’s get back to your arm. Essentially what we described above is what happens when your arm goes numb. The nerves are the communication superhighway for the body. From the brain to every organ, every extremity, and every little bit of the body. Without these express lanes, the brain will never know that you just stubbed your baby toe. Ouch. And your hand will never know that it should move off that still hot burner on the stove. Yikes. It’s a two-way street, both receiving info and sending instructions.

When something happens that blocks these nerves, then communication stops. Such as when the nerve is compressed. Just like the water from the hose. Or if we use the highway analogy, a big sixteen wheeler skid onto its side, blocking all traffic. For the nerves, this means communication between the brain and the extremities is stopped. If the nerve going to the arm gets compressed, no more signals in that particular nerve from the arm to the brain. And this is where that numb feeling comes from. The brain doesn’t ‘feel’ the arm being there anymore. And is some odd sort of way, it is not. Hence that creepy feeling that your arm belongs to someone else.

And that feeling when your arm starts ‘waking up’?

Why does my arm get that pins and needles feeling?

You mean paresthesia? That fancy medical word again?

Well, once the compression on the nerves is released, those nerves jump back to life. Really jump. In a sense at least. They get completely fired up again. And all of them. At the same time. That’s a lot of action to be happening at once. Hence those pins and needles that you feel.  So it’s actually a good sign. Things are getting back into action.

Now, let’s dig a little deeper.

Why does my numb arms keep falling asleep at night and waking me up?

I’m going to let you in on a neat little secret. It’s about the incredible defense mechanisms of the body. It’s quite amazing actually how the body runs all on its own. And even puts things in place to keep it running smoothly. Let’s take a look.

So far we know that the arm goes numb when it is compressed. Usually, once the pressure is released, the nerves come back to life.

But what happens if that pressure was to continue?

Big problems for the body. It can lead to long term damage for the nerves. And the nerves are not known for quick recoveries. Which can mean many things. Lots of pain, continuous numbness, weakness, and impaired movement to name a few. Essentially, things that you don’t really want to experience.

But never fear! The incredible defense system of the body is here!

Even while you are sleeping, behind the scenes, the nervous system is on constant alert. Making sure that things are running smoothly. When the brain notices that no signals are coming from a dormant arm, the alarm sounds.

“Sergeant, we have not received any news from the right arm. Right arm appears to be out of action. Repeat, the right arm is out of action”

“Sound the alarm! Code red! Code red! Alert the general!!!”

And what does this ‘general’, aka brain, do? It sends the signal to wake you up. So you can physically and conscientiously try to remove the pressure. And hence doing so before anything happens, such as long-term or even irreversible damage.

So annoying as it is, waking up is actually for your own protection.

Now, let’s get to the crux of the matter.

How to prevent this arm numbness?

Alright, this may seem like stating the obvious or even simply pure common sense. (Though it can also be argued that common sense is not so common). But in a lot of the cases of arm numbness while sleeping, the answer is really quite simple:

Adjust your position.

That’s it? Kuddos, Mr Sherlocke, you’ve solved the mystery.

And yes we did. At least for many, if not most people.

IMPORTANT NOTE: Sometimes there are other reasons the nerve can be affected. These usually combine with other symptoms. But this we’ll look at in another article. Our focus here is the common cause.

The way you sleep can often be the trigger (or in this case the blocker) for those nerves leading down your arm. When you initially lie down, all may seem fine. But as you drift deeper into dreamland, the pressure can start to get a bit too much.

Two simple ways you can prevent this are:

  1.  Change your sleeping position (try another side, move the way you position your arm, move your head, etc)
  2. Get yourself one of those wedge pillows. They have pretty neat ones with arm holes that are designed to take pressure of your shoulders. And some do even more nifty things. The most important one, of course, being no more numbness (Yippee! Start the celebrations!)

Who’d have thought that something so annoying could have such an easy answer?

The sum up

So now you have some info. For the next time you find yourself relaxing on a sandy white beach. Under swaying palm trees. Next to crystal clear tepid waters. Sipping your piňa colada. And then suddenly finding yourself yanked back to reality. Huddling on your side in fetal position. Under your layer of blankets. With subzero winds hollering outside. Snow dunes pilling up against your window. And finding this paralyzed arm connected to your shoulder. @#$%&!!!!!

Yes, now you know what is happening. And why it’s good that you woke up (Really? Yup, it is. Remember: your protective soldiers in action)

And even better, now you know how to fix it. Move and get a new pillow.

So you can keep enjoying that piňa colada the next time.

Quick Explanation for arms falling asleep at night waking me up

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