Why Does Your Arm Go Numb When You Sleep?

A numb, tingling sensation in your arms or hands can disrupt a good night’s rest. So, why does your arm go numb when you sleep, and what can you do about it?

By Nicole Gleichmann

May 23rd, 2022

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You wake up with a numb, pins-and-needles feeling in one or both of your arms. We’ve all experienced this at one point or another. So, why does this happen?

That sensation is known as paresthesia, and it all comes down to the nerves. It is the same thing that happens when your leg falls asleep from sitting in an odd position or when you get that numb, shooting sensation after you hit your funny bone.

There are multiple reasons why paresthesia can occur in your arms and hands at nighttime. Some of these are harmless, but others are a sign of an underlying health condition. We will cover both of these as well as how you can determine if it’s time to see your doctor.

The Top 5 Reasons Your Arm Goes Numb When You Sleep

1. You Put Pressure on Your Arm

Your sleeping position may be to blame for arm or hand numbness at night. Many side sleepers experience harmless paresthesia due to pinning the arm underneath the body. This is generally caused by nerve compression or a pinched nerve, resulting in tingling and numbness in the arms and hands.

It is the same reason why we experience body parts “falling asleep.” While many incorrectly assume that the pins-and-needles sensation is caused by restricted blood flow, it is actually due to nerve compression. Pressure on a nerve can temporarily hinder nerve function.

This type of paresthesia is temporary and harmless. Once you reposition, it’s only a matter of time before you find relief and can drift back to sleep.

If you find that this sensation is waking you up often, you may want to try sleeping on your back to ensure that it is indeed how you’re sleeping that’s causing the numbness and tingling. If you do not find relief, your paresthesia may be caused by an underlying medical condition.

2. Your Neck Is in a Weird Position

It is not only sleeping on your arms that can cause position-related tingling and numbness. When your neck is kinked or in a cramped position, you can wake up with full-arm paresthesia. Try lifting your arm over your head—if you find relief, it was likely caused by poor neck positioning.

Similar to side sleepers sleeping on their arm, if you believe that you are experiencing this numbness due to neck position, the solution is changing the position in which you sleep. Try to sleep in a position where your neck is elongated and properly supported. You might find that you need a new pillow that offers proper support, but not too much support. You want to allow a neutral spine and neck position while you sleep.

3. Diabetes

Diabetic neuropathy is a common diabetes complication caused by damage to the health and function of your nerves. This can make it so your nerves do not communicate as well with one another. Some of the most common symptoms include numbness, tingling, or weakness in your extremities, a condition known as peripheral neuropathy.

Peripheral neuropathy is so named because your peripheral nerves are damaged. These are the nerves that run through your arms and legs and into your feet and hands. It is believed to be caused by high blood sugar, which can lead to nerve damage and the resultant paresthesia in your hands and arms.

If you find that changing position doesn’t positively impact your paresthesia and you have diabetes, you may be suffering from peripheral neuropathy. Other common symptoms of peripheral neuropathy include:

  • Muscle weakness or fatigue
  • A loss of sensation (inability to feel pain, hot, or cold)
  • Pins-and-needles feeling during the day

Speak with your doctor right away if you feel like you might be experiencing symptoms of diabetic neuropathy. There are lifestyle changes and exercises that may help you find relief and slow disease progression.

4. Carpal Tunnel Syndrome

According to the Mayo Clinic, carpal tunnel syndrome is a common condition caused by the compression of the median nerve found in the carpal tunnel, a narrow passageway on the bottom side of your wrist.

This nerve compression can cause tingling, numbness, sharp pain, and weakness that usually first presents in your thumb, middle, and index fingers. Over time, this sensation can move throughout the wrist and into the palm of your hand. When it’s severe, it can wake you from sleep and make it hard to fall back asleep.

What causes carpal tunnel syndrome? Typically, it’s overuse or repetitive motion of our hands and fingers. Many of us spend tens of hours every week in front of our computer screens. With hours on end spent typing or using our mouse, we can cause compression in our carpal tunnel. Other risk factors include:

  • Sex: Women are more likely to suffer from carpal tunnel than men
  • Inflammation: Chronic inflammation can lead to increased pressure on your median nerve. This is common in people with inflammatory conditions like rheumatoid arthritis.
  • Obesity: Obesity increases your risk of carpal tunnel syndrome.
  • Fluid retention: If you are pregnant or undergoing menopause, your body can retain fluids which places pressure on the median nerve. This often resolves with time.
  • Diabetes: Diabetes can increase the risk of damage to your median nerve.

5. Vitamin B Deficiency

Vitamin B is a complex of vitamins that are essential for cellular health and function. When we do not get enough vitamin B, it can lead to paresthesia symptoms, particularly tingling in the arms, legs, feet, and hands.

While most of us get enough vitamin B through our diet, some people are at an increased risk of vitamin B deficiency. These include:

  • The elderly
  • Vegans
  • Vegetarians
  • Alcoholics or anyone who regularly consume excess alcohol
  • Those with digestive disorders like inflammatory bowel disease (IBD)

Your doctor can include a test to determine if you’re vitamin B deficient during a routine annual exam. Supplementation is usually sufficient to reverse the deficiency and its symptoms.

When to See Your Doctor

When paresthesia is caused by your sleep position, you can usually fix it by readjusting, buying a new pillow, or changing your sleep position. If you find that you cannot find relief through these means, it is probably time to visit your doctor. Another clue that you should visit your doctor is if you experience shooting pains along with the pins-and-needles sensation, or when you begin to feel these symptoms when awake.

Numbness and tingling in the arms and hands can be a sign of many different medical conditions. Your doctor can help you determine the cause, and with it, help to formulate a plan to address the underlying medical condition.

Final Thoughts

Waking up with numbness or tingling in your hands and arms is common, especially for side sleepers. However, paresthesia can also be a sign of an underlying medical condition. In order to improve your sleep and protect your health, be sure to speak with a medical professional if you struggle to find relief from nighttime paresthesia.