What does it mean for part of the body to fall asleep?
The medical term for this sensation isparesthesia.
There may be pain or other discomfort associated with paresthesia, especially as it wears off.
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This article explains the possible reasons why your arm might fall asleep at night.
It explains how the position you sleep in might cause paraesthesia, and when to see a healthcare provider.
What Causes This Sensation?
Paraesthesia is a symptom, not a medical condition of its own.
It can be a temporary symptom, like when your arm “falls asleep.”
Or, it can be a chronic (long-term) symptom of an underlying medication condition.
Many people believe that paraesthesia occurs due to loss of blood flow, but that’s not the case.
Paraesthesia is a nervous system problem.
It happens when a nerve in your arm, leg, or another extremity gets compressed.
Nerves carry sensory information from your body to your brain.
They allow you toperceive pain, temperature, pressure, and other sensations.
They enable voluntary movements,reflexes, and much more.
This is essentially what happens when you experience paraesthesia or your arm falls asleep.
Most people only notice it if they wake up while it is happening.
Your symptoms should resolve soon after you change your position and take pressure off of the compressed nerve.
Peripheral neuropathy is common.
Over time, the nerves may gradually become damaged, and this injury may be irreversible.
Vitamin B12 Deficiency
Another common cause of peripheral neuropathy isvitamin B12 deficiency.
This deficiency is typically detected in people ages 40 years and above.
Vitamin B12 plays a critical role in several body processes.
Carpal Tunnel Syndrome
Thecarpal tunnelis a passageway in the wrist through which passes the median nerve.
If the median nerve gets compressed in this tunnel,carpal tunnel syndromecan ensue.
Carpal tunnel syndrome is also a throw in of peripheral neuropathy.
Carpal tunnel syndrome is often resulting from repetitive movements, such as typing or sewing.
Genetic Disorders
Certain genetic disorders can predispose affected individuals to nerve injuries.
One such disorder is known as hereditary neuropathy with a predisposition to pressure palsies (HNPP).
HNPP leads to episodes of weakness and loss of sensation often associated with compression of single nerves.
The symptoms you experience depend on the location of the stroke.
Other possible symptoms of stroke include:
Stroke symptoms tend to happen suddenly.
Every minute counts when you are having a stroke.
Call 911 for immediate medical care en route to the hospital.
How Is Paresthesia Prevented?
When Should I Worry?
Most people experience their arm falling asleep on occasion.
Numbness, weakness, and tingling are possible signs of stroke and heart attack.
If it doesn’t go away or seems to be getting worse, you may need medical attention.
Summary
The sensation of your arm falling asleep at night is called paresthesia.
Paresthesia takes place if nerves get compressed, leading to tingling, numbness, or loss of function.
This is usually temporary and resolves within minutes of adjusting your body position.
Some conditions, like carpal tunnel syndrome, diabetes, and hypothyroidism can cause nerve damage (neuropathy).
These conditions may also result in weakness, numbness, or loss of sensation in your arms or elsewhere.
Ljungquist KL, Martineau P, Allan C.Radial nerve injuries.J Hand Surg Am.
2015;40(1):166-72. doi:10.1016/j.jhsa.2014.05.010
Sleep Foundation.Numbness in hands while sleeping: causes and remedies.
National Cancer Institute.The peripheral nervous system.
2020 Jan;10(1):1-13. doi:10.3389/fendo.2019.00929
Johns Hopkins Medicine.Peripheral neuropathy.
National Institute of Neurological Disorders and Stroke.Peripheral neuropathy.
Badar A.Neuropsychiatric disorders associated with vitamin B12 deficiency: an autobiographical case report.Cureus.
2022 Jan;14(1):e21476.
doi:10.7759/cureus.21476
Johns Hopkins Medicine.Carpal tunnel syndrome.
National Center for Advancing Translational Sciences.Hereditary neuropathy with liability to pressure palsies.
Johns Hopkins Medicine.Arm care after a stroke.
National Heart, Lung, and Blood Institute.Stroke symptoms.
UCLA Health.Lifestyle changes can help arm numbness at night.
U.S. Department of Health and Human Services.Get your blood pressure checked.
Keck Medicine of USC.Is arm numbness and tingling ever cause for concern?
2002;51(3):737-741. doi:10.1227/00006123-200209000-00023
