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Why Our Limbs 'Fall Asleep' And Why It's So Painful

Updated September 23, 2021 11.6k views9 items

Maybe you've sat on the couch and binged your favorite TV show for six hours, or maybe you slept in a weird position, but when you tried to move your arm or leg, something happened. It felt as if you had a phantom limb; it felt like it was there but it was unresponsive and numb, and within a few seconds, the numbness turned into a combined sensation of heat and pain. 

The medical name for this sensation is paresthesia, but most know it as a limb "falling asleep." It's a common sensation, unlike rare skin diseases or other bodily sensations, but not many know what causes the tingling feeling in limbs when they fall asleep - or why it hurts so much. Though it can be painful and alarming, there's usually no need for concern.

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  • Paresthesia Can Occur More Frequently During Pregnancy

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    Paresthesia is a common symptom of pregnancy, and there are a couple of reasons why pregnancy causes numbness and tingling in a person’s extremities. The hormonal change in a pregnant person's body is the main culprit. When pregnant, the body produces relaxin, a hormone that loosens ligaments for pelvic expansion to occur. In can have adverse side effects, though; when too much relaxin is produced, other joints in the body also become more flexible and collapse at points where stress can be placed on peripheral nerves.

    Pregnancy can also cause paresthesia solely in the lower body, according to Dartmouth Medical School. Similar to when a person gains weight or wears a tight belt, there is a chance that a nerve which runs from the brain down into the legs - the lateral femoral cutaneous nerve - can get caught under a ligament in the pelvis.

  • Menopause Can Worsen Cases Of Paresthesia

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    As if hot flashes weren't enough, menopause can also cause paresthesia and peripheral neuropathy, according to 34 Menopause Symptoms. Menopausal women may have enlarged blood vessels that could press onto nerves and cut off circulation. 

    Postmenopausal women are particularly at risk for carpal tunnel, a form of peripheral neuropathy localized in a person's hands because their wrist structure becomes enlarged and places undue stress on the nerves. 

     

  • Passing Out After Drinking Could Cause Long-Lasting Paresthesia 

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    Generally, waking up to a tingly arm or leg won’t hurt you, because your body is doing its job. Your body wakes you up to alert you that your nerves have been compressed, so you can move them out of that position. When someone falls asleep after drinking, however, their body may not alert them to the problem.

    If you pass out after a few drinks for an extended period and compress your nerves the entire time, it could result in “Saturday night palsy.” According to the National Center for Emergency Medicine Informatics, due to extended damage, the paralyzed feeling might last as long as a couple of days to months. For the feeling to stop, the body must repair the nerves' protective coating, called the myelin.

  • In Rare Cases, Paresthesia Can Be A Symptom Of A Worse Condition

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    Though it usually isn’t something to fear, tingling can be a sign of peripheral neuropathy, a type of nerve damage. Peripheral neuropathy tends to be a symptom of many other diseases. According to Everyday Health, it's a condition highly associated with diabetes; when a person with type 2 diabetes has high blood sugar for prolonged periods, they experience tingling in their feet and hands, and often it spreads to their arms or legs. If blood sugar levels are not controlled, then numbness can turn to pain and swelling.

    Peripheral neuropathy can stem from a variety of other serious conditions, including kidney problems, liver disease, or even tumors that are pressing on nerves. Lyme disease, HIV, and Lupus may also be tied to peripheral neuropathy.