7 reasons your left arm is tingling, from a pinched nerve to a heart attack — and when to call 911

• Tingling is fairly common and usually relates to a problem with your nerves or blood circulation.
• Possible explanations include your sleep position, diabetes, a mini stroke, or heart attack.

Tingling in your left arm is a pretty common sensation, though you might describe it with a different name, like prickling, "falling asleep," pins and needles, or numbness.

Like tingling, all of these are known medically as paresthesia. Depending on the cause, paresthesia can range from slightly noticeable to intensely uncomfortable and painful.

In general, tingling in your left arm relates either to a nerve issue or a problem with blood circulation — but the specific cause can range from something as minor as sleeping on your arm, to a major issue like a heart attack or stroke.

Note: You might use "numbness" and "tingling" interchangeably, but they mean slightly different things. Though they can have the same cause, tingling is a type of sensation, whereas numbness is a total inability to feel.

Below, you'll find seven explanations for tingling in your left arm and how to treat this symptom.

1. A pinched nerve in your neck

"A pinched nerve in the neck is one of the most common causes of tingling in the left arm," says Dave Candy, a physical therapist and owner of More 4 Life.

You may also feel pain, numbness, or weakness in your arm, depending on what's causing the pinched nerve and how severe it is.

One possible cause is age-related wear and tear, called cervical spondylosis, when disks in your vertebrae thin and weaken. To compensate, your body can grow bone spurs to support the weakened disks. The downside, though, is that spurs can compress nerves, causing pain or tingling in your arm.

A herniated disk can also cause a pinched nerve. When the hard outer layer of a spinal disk weakens and cracks, whether due to aging or injury, the gel-like substance inside the disk can leak out and put pressure on your spinal nerves, causing tingling in your arm.

Keep in mind a pinched nerve in your neck won't always cause pain in your neck — tingling in your arm may be the only symptom.

What to do next: You can often treat a pinched nerve in your neck at home with the RICE method — rest, ice, compression, elevation — or with nonsteroidal anti-inflammatory drugs (NSAIDS), like Advil or Motrin.

If the tingling doesn't improve, a good next step involves checking in with your doctor. You'll also want to call your doctor if you notice any weakness in your hands, fingers, or arm.

It's especially important to get medical attention if you feel numbness or tingling along your bicep and forearm to your thumb, or on the back of your upper arm, down your forearm to your middle finger. The path tingling takes down your arm can help indicate which spinal nerve is being compressed.

Your doctor might recommend:

• Physical therapy
• Steroid medications, like prednisone, either orally or by injection
• Immobilization, which involves wearing a neck collar to keep your neck from moving

2. Heart attack

During a heart attack, a coronary artery is completely or partially blocked, along with nerves that supply the heart. This lack of blood flow can indirectly cause tingling or numbness in the left arm, says Dr. Sean Ormond, a specialist in interventional pain management at Atlas Pain Specialists.

Common signs of a heart attack include chest pain or pressure and shortness of breath. But heart attacks can also have subtle signs that may go unnoticed or be mistaken for other health concerns, especially in women and older adults. Other potential signs of a heart attack include:

• Nausea
• Indigestion
• Cold sweats
• Dizziness
• Upper back pressure or pain

What to do next: A heart attack can be life-threatening. If these symptoms come on suddenly, it's best to get emergency medical attention by calling 911 — even if your symptoms don't feel all that severe.

3. Type 2 diabetes

Type 2 diabetes and consistently elevated blood sugar can cause peripheral neuropathy — damage to the nerves outside of the brain and spinal cord, Ormond says.

This type of nerve damage usually begins in the feet and legs, but it can also affect your hands and arms as it progresses. Along with numbness and tingling, it can cause a burning sensation or sharp pain in your extremities.

It can have other serious consequences, too: If you can't fully feel your arm, you may have a harder time noticing changes in temperature, pain, or injuries that could lead to dangerous infections.

What to do next: To lower your risk of peripheral neuropathy, you can:

• Manage your blood sugar
• Aim to exercise regularly, if you're able. Current guidelines recommend either 150 minutes per week of moderate aerobic exercise, like brisk walking or swimming, or 75 minutes per week of intense aerobic exercise, like running or aerobic dancing.
• Eat a balanced diet that features a variety of fruits and vegetables, whole grains, and lean proteins.

You should seek prompt medical care if you start to notice unusual tingling or numbness in your hands and feet, as early treatment can help prevent further nerve damage.

4. Transient ischemic attack (mini stroke)

A transient ischemic attack (TIA), also called a mini stroke, can cause temporary tingling in your limbs, including your left arm.

TIAs occur when a blockage temporarily disrupts blood flow to the brain. Unlike a stroke, which often has severe and long-lasting repercussions, symptoms of a TIA typically last just a few minutes — they come on suddenly and usually will resolve within one hour to one day.

Along with tingling, weakness, or numbness in your arm, a TIA can cause:

• Slurred or unclear speech
• Difficulty understanding other people's speech
• Balance issues and lack of coordination
• Double vision, blurred vision, or temporary vision loss

What to do next: Though TIAs don't cause permanent damage, they can suggest you have a higher risk of stroke. About one in three people who have a TIA will go on to have a stroke, and half of those strokes occur within one year of a TIA.

If you experience any symptoms of a TIA, you should call 911 or go to the emergency room right away for an evaluation.

Your doctor may prescribe blood thinners like aspirin to help prevent the blood clots that can cause a stroke.

In some cases, your care team may recommend surgery to clear your carotid artery of plaques which can lead to stroke, either by:

• Endarterectomy: The surgeon will make an incision, remove the plaques, and close the artery again.
• Angioplasty: The surgeon will insert a small mesh tube, called a stent, into the artery to keep it clear and open.

5. Carpal tunnel syndrome

Carpal tunnel syndrome can develop due to compression of the median nerve, which gives sensation to parts of your hand.

"Carpal tunnel syndrome is usually caused by repetitive use of the hands such as manual labor, typing, using a mobile phone too much, or working on an assembly line," Candy says.

With carpal tunnel syndrome, you'll mainly feel tingling or numbness in your thumb, index, and middle finger, typically on one side of your body, but you could also experience tingling and pain that travels up your forearm.

What to do next: A healthcare professional can diagnose carpal tunnel syndrome and recommend treatment, which may include:

• A wrist brace: When worn at night, a brace keeps your wrist straight, putting less pressure on the median nerve.
• Steroid injections: Cortisone and other steroids can help ease inflammation and swelling of the tendons in your wrist, which reduces compression of the median nerve.
• Surgery: Carpal tunnel release, a brief outpatient surgery, involves a surgeon cutting the ligament in the wrist that is compressing the median nerve — most people will be back to normal activities within four to six weeks.

6. Multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system — the brain and spinal cord — that affects nearly one million people in the United States.

In MS, damage and deterioration of the myelin sheath, or the lining of your nerves, can cause a wide range of symptoms. Tingling in your arm is often an early symptom — but unexplained tingling in your arm doesn't always suggest MS.

With MS, you'll likely also experience numbness and tingling in your legs, torso, and face — not just your left arm.

What to do next: It's a good idea to make an appointment with a healthcare professional if you experience tingling in your arm along with other common initial symptoms of MS, such as:

• Muscle weakness
• Balance problems
• Excessive fatigue
• Vision problems, including blurred or double vision or loss of color vision, especially when these issues affect just one eye

There is no cure for MS. Treatment focuses on managing symptom flare-ups with medications like glucocorticoids and physical or occupational therapy to help maintain mobility and function. Medications that modify immune system activity can also help reduce inflammation and slow the progression of MS.

7. How you sleep

Tingling in your left arm can also relate to your sleeping position.

Certain sleep positions can cause the nerves in your arm or neck to compress during the night. For example, this might happen if you:

• Sleep with your arm bent or your hand in a fist
• Rest your head on your arm while sleeping
• Sleep on your stomach
• Sleep on your side without supporting your arm

What to do next: If you consistently wake up with your arm tingling, it could help to try a different sleep position. To find a more comfortable sleep position, try:

• Keeping your hand flat on a pillow, rather than closed into a fist
• Sleeping on your back, with your arms at your side or on pillows. This is the best position to support the nerves in your neck and arm that can cause tingling.
• Sleeping on your side with a pillow in front of you to support your arm and help keep your wrist and fingers straight.
• Placing a pillow under your knee on the side you face when sleeping on your stomach. This will ease some of the pressure on your neck.

Insider's takeaway

Tingling in your left arm is a common sensation. If it happens now and then but goes away on its own, you most likely have nothing to worry about.

However, you'll want to pay attention to tingling in your arm that keeps coming back, shows up with other symptoms, or gets worse over time.

This kind of tingling can suggest an underlying health condition, so you'll want to make an appointment with your doctor as soon as possible. They can help determine the cause of the tingling and offer more guidance on options for treatment.