It’s understandable to be worried about numbness in your right or left arm. Keep in mind that the sensation may be temporary, caused by something like sleeping in the wrong position, which is nothing to be concerned about.
However, numbness may be caused by a sudden health emergency, nerve disorder, or nutritional deficiency. If numbness recurs or includes symptoms like chest pain or dizziness, seek medical assistance right away.
Determining whether numbness occurs suddenly or gradually and whether there are other symptoms can help your healthcare provider diagnose and treat the condition.
Poor Circulation
Poor blood circulation in your arm could cause numbness and tingling because the nerves cannot get enough oxygen. A number of conditions can interfere with normal blood flow. These include:
- Atherosclerosis, plaque buildup in the arteries that may require medication or surgery
- Severe frostbite that can damage the blood vessels; it may be resolved with proper warming and wound care, but some cases may require amputation
- Vasculitis, inflammation of the blood vessels that can be treated with medication
Sleep Position
One of the most common examples of sudden numbness and tingling is the feeling that your arm has"fallen asleep." This usually occurs after sleeping in a poor position or leaning on the arm for a long time.
Known as paresthesia, this sensation is related to the compression or irritation of nerves.
Sleeping on your stomach is likely to cause loss of blood flow to the nerves while side sleeping may be less of a risk as long as you keep your wrists straight. Paying attention to proper spine alignment when you sleep is the best way to prevent arm numbness.
Nerve Injuries and Disorders
While arm numbness related to sleep positions or temporary pressure resolves on its own quickly, other nerve issues may be more serious.
Numbness that persists may be related to an injury or underlying health problem that affects the brachial plexus, a group of nerves that runs from the lower neck to the upper shoulders and controls movement and sensation in the arms.
Possible injuries that affect these nerves include:
- Herniated disc, caused by aging or trauma and resulting in the soft material in the center of a disc leaking out and pressing on the nerve root.
- Birth injuries such as Erb-Duchenne palsy and Klumpke's palsy
- Burner or stinger injuries that affect the neck and shoulders and are often related to impact sports injuries
- Backpacker's palsy caused by pressure on the shoulders
- Traumatic nerve root avulsion, a severe injury in which spinal nerves are damaged
Diseases and disorders that can cause numbness in the arms include conditions that affect the nervous system such as multiple sclerosis, fibromyalgia, Raynaud phenomenon,and shingles (herpes zoster).
When Numbness Is a Sign of a Serious Health Condition
- Stroke: This is a medical emergency in which a blockage prevents blood from getting to the brain. One sign of a stroke is a tingling sensation on one side of the body. You may also be unable to move one or more limbs. Seek emergency medical care to treat a stroke.
- Heart disease: When your heart is damaged, blood cannot flow and it can lead to a minor or major heart attack. Signs of a heart attack include numbness in one or both arms (it's not always the left arm). Pressure and pain in the chest and shortness of breath are other signs that you should call 911 and get medical attention immediately.
- Osteoarthritis of the spine: Wear and tear in the spine's joints can lead to spinal stenosis, the narrowing of the spinal canal that causes the nerves to be compressed. Physical therapy and medication are used to manage spinal stenosis.
- Cancer: Neoplasm, tumors, can affect the nerves of thebrachial plexus causing loss of feeling in the arms. Cancers of the breast and lung are most likely to cause this problem.
- Diabetes: Loss of feeling in your arms can be a sign of peripheral neuropathy, which is commonly caused by uncontrolled diabetes. Treatment requires you to manage your blood sugar; oral and topical medications may also be used.
Medication and Arm Numbness
The relationship between arm numbness and medication is complex:
- Many medications, like Neurontin (gabapentin), can be used to alleviate the uncomfortable sensations of arm numbness.
- Some medications may cause numbness as a side effect.
- Some medications can cause complications—and arm numbness could be a symptom of the complications.
Be sure to tell your healthcare provider about all medications you’re taking to determine a relationship between the medication and your sensory changes.
Vitamin Deficiency
Diabetes is not the only cause of peripheral neuropathy. Nutritional deficiencies and vitamin imbalances can also damage nerves and cause a loss of sensation in the left or right arm.
The most common sources of problems are a vitamin B12 deficiency and an excess of vitamin B6. Alcohol dependence and other disorders that affect nutritional intake can also lead to nerve damage.
Summary
Arm numbness or tingling are fairly common symptoms that can be caused by various medical conditions. Sometimes this symptom results from your arm “falling asleep,” and it could resolve after just a few minutes.
However, arm numbness and tingling may also occur due to neuropathy, a chronic and progressive type of nerve damage. It may also suddenly occur due to serious conditions, such as a heart attack or a stroke.
If you are experiencing a sudden onset of arm or hand numbness lasting more than a few minutes, you should seek prompt medical attention. If you’ve been having intermittent numbness in your arms or hands, you should make an appointment to see a healthcare provider as soon as possible.
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Bryan, L., Singh, A. "Numbness in Hands While Sleeping: Causes and Remedies." Sleep Foundation.
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Centers for Disease Control and Prevention.Stroke signs and symptoms.
National Heart, Lung, and Blood Institute. What Is a Heart Attack?
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By Heidi Moawad, MD
Dr. Moawad is a neurologist and expert in brain health. She regularly writes and edits health content for medical books and publications.
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