Paresthesia: Why Your Body Parts Tingle and Fall Asleep

Woman's feet in pink socks sticking out from under a blanket
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What's happening when you're watching TV or reading in your favorite chair, leg slung over the chair's arm as you relax after a long day, and your arm or foot falls asleep? Your legs or arm may feel funny as you try to move. They may feel numbness, a pins and needles sensation, or almost painful buzzing. You find that getting your muscles to work properly is nearly impossible.

When we feel a body part fall asleep, it may be paresthesia.

Unlike commonly thought, the situation has less to do with blood circulation and more to do with nerves.

Paresthesia is an abnormal sensation felt in your body due to compression or irritation of nerves. The irritation of your nerves may be mechanical—as in the "pinched nerve" example above—or it may be due to a medical condition, injury, or illness. The symptoms of paresthesia may vary from mild to severe, and they may be fleeting or long-lasting.

Knowing what paresthesia is and how it should (and should not) behave can help determine when—and if—you need medical attention for it.

What Paresthesia Feels Like

Paresthesia may cause various symptoms in your arms or legs. These may include:

  • Numbness and tingling
  • Pins and needles
  • Itching
  • Difficulty contracting your muscles and using the affected arm or leg
  • A feeling of cold
  • Burning feelings
  • A feeling like your leg or arm has fallen asleep

Symptoms are typically felt in one arm or leg, but both arms and legs may be affected depending on the cause of your abnormal sensations felt from paresthesia.

The symptoms you feel often only last for a short time, and usually, they are not intense or severe. But in some cases, paresthesia may last a long time. In these cases, you may need to see a doctor to figure out the cause of your symptoms.

Causes

Rest assured, most cases of pins and needles or your foot falling asleep are simply caused by assuming an unnatural position and are quickly resolved by moving around a bit.

Most cases of paresthesia can be prevented by sitting with proper posture while watching TV or reading. Other causes can include:

  • Compression of a spinal nerve from a herniated disc
  • Compression of a nerve due to assuming poor postures and positions
  • Tension and traction or pulling on a nerve
  • Altered nerve function due to illness or disease like diabetes
  • Central nervous system conditions, such as a stroke or multiple sclerosis (MS)

When to Get Help

How do you know when your pins and needles and foot falling asleep is a problem? When should you seek out medical help for your paresthesia?

In general, if your numbness and tingling symptoms come on while you are sitting in an awkward position, then they should go away within a few minutes of moving around. After a half-hour or so, you should be back to your normal self.

If your foot or arm remains tingling or difficult to move after an hour, it may be time to check in with your doctor. If the cause of your paresthesia is due to an acute central nervous system condition, like a stroke, then time is of the essence. Getting the right diagnosis and medical care immediately is necessary.

If you have paresthesia that comes on gradually, and if you have a medical condition like diabetes, you may not be too concerned when your pins and needles or numbness worsens.

It may just be due to high blood sugar. But, a worsening case of paresthesia should still be monitored by your doctor. Peripheral neuropathy caused by diabetes usually starts with a feeling of paresthesia in your foot or feet and it needs to be managed appropriately by your doctor.

Diagnosis

Anytime you feel pins and needles or numbness in your arm or leg, this is paresthesia. Most of the time you know exactly what to do to take care of the problem: shake your arm or leg a bit, get in a better position, and wait a few minutes. This self-care treatment that we have all learned over time most often helps take pressure off your irritated nerve and quickly gets you feeling back to normal again.

This is most often effective when your leg or arm falls asleep while you are sitting in an awkward position. Change your position, wait a bit, and your paresthesia symptoms should subside.

If your symptoms of paresthesia are long-lasting, you may need to visit your doctor to get an accurate diagnosis of the condition that is causing your abnormal leg or arm sensations. He or she can work with you to understand your problem and perform the right diagnostic studies to determine the cause of your condition.

Common diagnostic procedures for paresthesia may include:

The tests your doctor chooses to perform to diagnose paresthesia depends on your clinical presentation. A careful examination by your doctor will lead him or her to investigate different avenues as to the cause of your paresthesia.

For example, if your paresthesia is accompanied by back or neck pain and you have altered spinal motion, your doctor may suspect compression of a spinal nerve as the cause of your problem. If you have a history of diabetes that is poorly controlled, your doctor may suspect peripheral neuropathy as the culprit.

The test results your doctor obtains can give you an accurate diagnosis of your condition and can lead you to the right treatment.

Treatment

For persistent paresthesia, when your symptoms don't subside with shaking out your body, correct treatment depends on what is causing your abnormal sensations of pins and needles or numbness.

First and foremost, if your symptoms are caused by a central nervous condition like MS or a stroke, you need to work closely with your doctor to get the right treatment. Medicine may be necessary to help your symptoms and your doctor can give you an understanding of how your symptoms should change over time. Sometimes, physical therapy may be ordered to help improve your overall functional mobility.

If your paresthesia is caused by compression of a spinal nerve, as in a condition like sciatica, you may benefit from a course of physical therapy to help get pressure off of your nerve. Your physical therapist may prescribe spinal exercises to perform that can relieve compression of your nerve and restore normal sensations and motion to your arm or leg. If weakness is present, your PT may prescribe strengthening exercises to restore normal mobility.

If a herniated disc is causing the abnormal sensations in your arm or leg, and if you have failed to improve with conservative measures like PT, you may benefit from surgery to help decrease pressure on your nerve or nerves. The goal of surgery, like a laminectomy or discectomy, is to decompress the nerve and allow it to function normally again. After surgery, you may benefit from physical therapy to help you regain normal mobility again.

Sometimes, peripheral neuropathy from diabetes may cause paresthesia and abnormal sensations in your foot or feet. Often in these cases, the symptoms are relatively permanent and may change only slightly with medication.

Bottom Line: The treatment you receive for paresthesia depends on your specific diagnosis, and your doctor can help determine the best course of action for you to take.

A Word From Verywell

If you have numbness or tingling and pins and needles in your foot, leg, or arm you may have paresthesia. In most cases, there is no need to worry; the symptoms will pass as you move around a bit. If you have lingering symptoms or if your foot is asleep and not waking up, then you need to see your healthcare practitioner for diagnosis and treatment. In most cases, simple things can be done to treat your condition so you can relieve your paresthesia and return to your normal work and recreational activities.

Source:

Razazian, N. et al. Exercising impacts on fatigue, depression, and paresthesia in female patients with multiple sclerosis. Med Sci Sport and Exercise: 48(5); 2015: 796-803. DOI: 10.1249/MSS.0000000000000834

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