Why Do My Arms Fall Asleep at Night?

Many people experience the uncomfortable sensation of numb or “sleeping” arms during the night — a condition known as paresthesia.

You might wake up with tingling, stiffness, or loss of sensation in one or both arms. While it’s often harmless and temporary, recurring nighttime numbness can sometimes indicate an underlying issue.

Here’s what causes it and when to seek medical help.

What Does It Mean When Your Arm Falls Asleep?

When your arm “falls asleep,” it means that nerves or blood vessels are compressed, interrupting normal nerve signaling or blood flow.

This causes a tingling or prickling feeling — sometimes described as “pins and needles.”

The sensation usually resolves once pressure is relieved and circulation returns to normal, but persistent or frequent symptoms can suggest nerve compression or irritation.

Common Causes of Numb Arms at Night

1. Sleeping Position

The most frequent cause of nighttime arm numbness is simply how you sleep.

Lying on your arm, tucking it under your pillow, or sleeping with your head resting on your arm can compress nerves or blood vessels, leading to temporary numbness.The sensation typically disappears within minutes after changing position.

2. Nerve Compression (Carpal Tunnel Syndrome)

Carpal tunnel syndrome occurs when the median nerve — running through the wrist — becomes compressed.

It’s common in people who perform repetitive hand movements or use computers extensively.

Symptoms: Tingling or numbness in the thumb, index, and middle fingers, often worse at night. Over time, grip strength may weaken.

3. Thoracic Outlet Syndrome (TOS)

This condition happens when nerves or blood vessels between the collarbone and first rib are compressed.

TOS can cause pain, weakness, or numbness that worsens at night or with certain arm positions.

Symptoms: Arm heaviness, tingling, or weakness, sometimes accompanied by shoulder or neck discomfort.

4. Poor Circulation

Restricted blood flow due to awkward sleeping positions or medical conditions like diabetes or hypertension can cause the arms to feel numb or tingly.

Improving circulation by adjusting posture or managing underlying health issues can help.

5. Nerve Damage or Inflammation

Chronic or severe nerve compression — such as from a herniated disc, neck injury, or inflammation — may cause persistent numbness.

Symptoms: Long-lasting tingling, radiating pain from the neck to the hand, or noticeable muscle weakness.If these occur, medical assessment is essential.

When Should You Be Concerned?

Occasional numbness is common and harmless, but you should see a doctor if you experience:

• Persistent numbness lasting more than 30 minutes

• Severe pain accompanying the tingling or loss of sensation

• Weakness or loss of grip strength

• Frequent nighttime awakenings due to arm discomfort

These signs could indicate conditions such as nerve entrapment, vascular problems, or metabolic disorders that require professional evaluation.

How to Prevent Your Arms from Falling Asleep

• Adjust your sleeping position: Avoid lying directly on your arms or bending them sharply under your body.

• Use ergonomic pillows: Support your neck and wrists properly to relieve nerve pressure.

• Take breaks from repetitive tasks: Stretch your wrists, arms, and shoulders regularly if you work at a desk.

• Address underlying issues: Manage diabetes, blood pressure, or neck injuries with your doctor’s help.

• Stay active: Gentle exercise improves blood flow and nerve health.

Summary

Arms that “fall asleep” at night are usually caused by temporary nerve or blood vessel compression due to sleeping posture.

In most cases, it’s harmless — but frequent or persistent numbness, pain, or weakness may point to conditions like carpal tunnel syndrome, thoracic outlet syndrome, or nerve injury.

Small changes in sleeping habits and posture can often relieve symptoms, but if discomfort continues, seek medical assessment to rule out underlying causes.

Sources

• Beckenbaugh RD, et al. (2004). The effects of thoracic outlet syndrome on upper extremity function. J Orthop Sports Phys Ther, 34(7):380–386.

• Kaplan MS, et al. (2016). Carpal tunnel syndrome: A review of treatment strategies. J Am Acad Orthop Surg, 24(5):335–343.

• Maughan RJ, et al. (2015). The physiological effects of sleeping position on upper limb function and comfort. Sleep Health, 1(2):100–104.

• Deltombe T, et al. (2013). Carpal tunnel syndrome and its impact on hand function. J Hand Surg Am, 38(1):116–121.

• Freeman R, et al. (2009). The pathophysiology of paresthesia and neural dysfunction. J Neurol Neurosurg Psychiatry, 80(4):391–397.