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Leg numbness may appear after prolonged sitting, sleeping in an uncomfortable position, or the habit of sitting with one leg crossed over the other. In such cases, sensitivity usually recovers quickly after changing position and making light movements. However, if leg numbness recurs, lasts for a long time, or occurs without an obvious reason, it is important to determine what it is associated with.

Attention should also be paid to accompanying symptoms. If the legs hurt and become numb at the same time, and weakness, burning, swelling, lower back pain, or gait disturbances appear, the cause may be spinal diseases, nerve damage, or impaired blood circulation.

In this article, we will review the main reasons why the legs become numb and explain how the location and time of onset of numbness help to approximately determine the source of the problem. We will also discuss what can be done independently, which exercises may relieve the condition, and when it is necessary to see a doctor.

Why the legs become numb

The most common reasons why the legs become numb include:

  • prolonged time spent in an uncomfortable position;

  • compression or damage to a peripheral nerve;

  • osteochondrosis, a disc herniation, or narrowing of the spinal canal if they irritate a nerve root;

  • diabetes mellitus and other causes of polyneuropathy;

  • vitamin B12 deficiency and other metabolic disorders;

  • diseases of the arteries of the lower limbs;

  • injuries, surgeries, or prolonged restriction of mobility.

Assessing the location of the symptom helps narrow down the list of possible causes. Therefore, the doctor always clarifies these details during the examination. 

Why the legs become numb below the knees

If the legs become numb below the knees, it is important to determine whether sensitivity has decreased equally on both sides. Symmetrical numbness of the lower legs and feet occurs more often with polyneuropathy, whereas a limited area on one side may correspond to the region for which a particular nerve is responsible.

Possible peripheral nerve damage may be indicated by:

  • simultaneous numbness of both feet;

  • burning or tingling in the toes;

  • reduced sensitivity to pain and temperature;

  • worsening of unpleasant sensations at night;

  • gradual spread of symptoms upward from the feet.

According to the National Institute of Neurological Disorders and Stroke, peripheral nerve damage may manifest as numbness, tingling, burning, pain, and muscle weakness.

Such symptoms are also possible with diabetes mellitus, confirmed vitamin B12 deficiency, kidney diseases, thyroid dysfunction, and toxic nerve damage. The cause cannot be determined solely by the nature of the sensations because different diseases may have similar manifestations.

A local decrease in sensitivity on the outer surface of the lower leg and the upper part of the foot sometimes occurs due to compression of the peroneal nerve near the knee. This may happen after prolonged sitting with crossed legs, squatting, an injury, or the use of a tight bandage.

Doctors at «Oxford Medical» note that swelling, heaviness, a feeling of fullness, and enlarged superficial veins may accompany varicose veins. However, numbness is not one of the main manifestations of the condition, so loss of sensitivity should not be attributed solely to venous disorders without a medical examination.

Why the right or left leg becomes numb above the knee

One-sided thigh numbness may occur due to nerve compression in the groin area or irritation of a nerve root in the lumbar spine. To determine the possible cause, the exact area of impaired sensitivity, the presence of muscle weakness, and the connection with trunk movements are more important than the side affected.

To understand why the right leg becomes numb above the knee, it is necessary to determine whether the unpleasant sensations are limited to the outer surface of the thigh. Burning, tingling, and superficial numbness in this area may occur when the lateral femoral cutaneous nerve is compressed. Muscle strength usually does not decrease in this case.

Nerve compression may be promoted by:

  • tight clothing or a tight belt;

  • weight gain;

  • pregnancy;

  • an injury in the pelvic area.

The unpleasant sensations sometimes intensify during prolonged standing or walking.

If the left leg becomes numb above the knee, the same signs are assessed because such a disorder may occur on either side. When the area of reduced sensitivity does not extend below the thigh and there is no weakness, damage to a superficial nerve is more likely.

If the right leg becomes numb from the buttock to the lower leg or foot and the symptom worsens during bending, prolonged sitting, coughing, or sneezing, nerve root irritation is possible. Similar manifestations often accompany back pain, shooting pain, and burning along the limb.

Doctors at «Oxford Medical» explain that weakness when lifting the foot, difficulty walking up stairs, or frequent stumbling may indicate damage not only to sensory but also to motor nerve fibers. With such symptoms, it is necessary to see a doctor and undergo an examination.

Why the feet become numb

Why the feet become numb

Foot numbness may begin in the toes, sole, heel, or outer edge. A symmetrical decrease in sensitivity occurs more often with polyneuropathy, while a local decrease occurs with compression of an individual nerve. A combination of cold feet and pain while walking requires assessment of arterial blood flow.

Possible impaired blood supply may be indicated by:

  • one foot being constantly colder than the other;

  • the skin becoming pale or bluish;

  • calf pain occurring while walking and subsiding after stopping;

  • wounds, scratches, or cracks taking a long time to heal;

  • the hair on the lower leg becoming sparser;

  • the nails growing more slowly.

As noted by the American Heart Association, with peripheral artery disease, pain or discomfort in the legs often occurs while walking and decreases after rest. Coolness of the feet, skin changes, slow wound healing, and numbness are also possible.

Doctors at «Oxford Medical» warn that a sudden loss of sensitivity together with pronounced coldness, severe pain, paleness, or bluish discoloration of the foot requires emergency care. Such manifestations may indicate an acute disruption of the blood supply. 

Why the legs become numb at night

If the legs become numb at night because of an uncomfortable position and sensitivity returns within a few minutes after changing position, temporary nerve compression may be the cause. Regular episodes that do not depend on body position, persist during the day, or are accompanied by burning and pain require examination.

With polyneuropathy, tingling, burning, and discomfort in the feet often become more noticeable at rest. If the symptom begins in the lower back and spreads down the limb, nerve root irritation is possible.

Numbness should be distinguished from restless legs syndrome. It is characterized by a strong urge to move the limbs that occurs in the evening or during rest. Walking brings relief, but a loss of sensitivity is usually absent.

Why the leg becomes numb after surgery

After a surgical procedure, the leg may become numb because of the residual effect of anesthesia, tissue swelling, a prolonged immobile position during the operation, or an effect on nerve structures. After spinal or epidural anesthesia, sensitivity and movement usually recover gradually.

Numbness around the surgical incision may be associated with damage to small nerves. Recovery of sensitivity sometimes takes several weeks or months, while a small area may remain less sensitive for longer. The duration depends on the type of operation, the location of the incision, and the extent of the procedure.

It is necessary to contact a doctor if:

  • the area of reduced sensitivity is increasing;

  • weakness in the limb is worsening;

  • it has become difficult to move the foot or toes;

  • severe or increasing pain has developed;

  • significant swelling has appeared;

  • the foot has become cold or has suddenly changed color;

  • the condition has worsened after an earlier improvement.

Doctors at «Oxford Medical» recommend not waiting for a scheduled examination if the range of movement suddenly decreases or the numbness spreads after surgery. First, it is necessary to contact the doctor who performed the procedure and describe the changes.

What to do when the legs become numb

What to do when the legs become numb

The approach depends on the duration of the numbness, its location, and accompanying manifestations. A single episode after an uncomfortable position usually does not require treatment. However, recurring numbness of the lower limbs that occurs without an obvious reason or is accompanied by pain and weakness requires examination.

If the sensory disturbance regularly returns, a neurologist consultation is necessary. The doctor will check reflexes, muscle strength, and sensitivity and, based on the examination results, determine which tests are appropriate.

Doctors at «Oxford Medical» note that before the cause has been established, the numb area should not be intensively massaged, rubbed, or warmed. Vitamins, painkillers, or vascular medications should also not be taken independently. The treatment method depends on where the disorder has occurred: in a nerve root, peripheral nerve, blood vessels, or as a result of another disease.

What to do if the leg has fallen asleep

If the leg has fallen asleep after sleeping or sitting for a long time, do not stand up abruptly right away. Due to the temporary decrease in sensitivity and movement control, the foot may be placed incorrectly, balance may be lost, or an injury may occur.

Proceed in sequence:

  1. Change position and remove pressure from the limb.

  2. Loosen tight shoes or clothing.

  3. Carefully move the foot and compare the sensitivity of the right and left feet.

  4. Put weight on the leg only after sensitivity and normal movement control have returned.

Doctors at «Oxford Medical» warn that after short-term nerve compression, tingling and numbness usually gradually decrease. If sensitivity does not return, the limb should not be loaded. Pay attention to whether there is pronounced weakness, severe pain, swelling, coldness, or a change in skin color. If such symptoms are present, urgent medical care is necessary.

How to get rid of leg numbness

If the left or right leg becomes numb without being connected to an uncomfortable position, the symptom can be eliminated only after its cause has been established. During the examination, the doctor checks sensitivity, muscle strength, reflexes, coordination, and gait and then determines the required scope of diagnostic testing.

Depending on the indications, the following may be recommended:

If the numbness is associated with an intervertebral disc herniation, the doctor evaluates its location, its effect on the nerve root, the severity of pain, impaired sensitivity, and muscle strength. In most cases, treatment of an intervertebral disc herniation may include pain-relieving medications, individually selected exercises, and physical rehabilitation. Surgery is considered mainly when muscle weakness is increasing, severe pain persists, or there are other signs of significant compression of nerve structures.

When the cause is compression of an individual peripheral nerve, the pressure on it must first be removed. Sometimes it is sufficient to change the position used while working, stop sitting with crossed legs, or replace tight footwear. If the symptoms persist, the doctor may recommend rehabilitation, the use of an orthosis, or another treatment.

With polyneuropathy, therapy is directed at the disease or disorder causing the nerve damage. In diabetes mellitus, treatment is adjusted to stabilize glucose levels, while confirmed vitamin B12 deficiency is corrected according to the regimen prescribed by the doctor. Medications that affect the transmission of pain signals in the nervous system may be prescribed to reduce neuropathic pain, burning, and tingling.

Why the legs become numb at night

Exercises for leg numbness

Simple movements may help when the loss of sensitivity occurred after remaining in one position for a long time. Exercises should not be performed in cases of acute pain, significant swelling, a recent injury, sudden muscle weakness, or pronounced coldness of the limb.

After movement control has been restored, the following can be performed:

  1. Foot flexion. Pull the toes toward you and then smoothly point them forward. Repeat 8–10 times.

  2. Toe movements. Slowly curl and straighten the toes 10–15 times.

  3. Foot rotations. Make 5–8 circular movements in each direction.

  4. Heel raises. While sitting, place the feet on the floor and raise the heels without lifting the toes.

  5. Calm walking. When sensitivity has fully returned, walk around the room for several minutes.

The movements should be smooth and should not cause pain. If numbness intensifies during the exercises, shooting pain develops from the lower back, or weakness or dizziness occurs, the activity must be stopped.

After surgery, an injury, or in the presence of spinal diseases, the exercise program is selected individually. Exercises that help one person may increase nerve irritation in another.

When it is necessary to see a doctor

See a doctor if:

  • the left or right leg becomes numb and the numbness does not resolve after changing position;

  • the symptom regularly occurs at night;

  • burning or persistent pain has appeared;

  • it has become difficult to lift the foot;

  • you have started stumbling more often;

  • balance is impaired;

  • sensitivity in both feet has decreased;

  • the unpleasant sensations are gradually spreading upward.

Doctors at «Oxford Medical» warn that sudden numbness of the arms or legs requires particular attention. If sensitivity decreases on one side and facial asymmetry or speech, vision, or coordination disturbances occur at the same time, an ambulance must be called immediately, even if the condition improves after a few minutes. This may be a manifestation of a stroke. 

The following also require an urgent examination:

  • sudden weakness or loss of movement in a limb;

  • bilateral numbness that is rapidly worsening;

  • reduced sensitivity in the perineal area;

  • difficulty urinating or loss of bladder control;

  • sudden coldness, paleness, or bluish discoloration of the foot;

  • severe pain after an injury or surgery.

A combination of bilateral symptoms in the legs, perineal numbness, and urinary disturbances may occur with dangerous compression of the nerve roots in the lower part of the spine. Cauda equina syndrome requires urgent examination in a hospital.

Doctors at «Oxford Medical» recommend not postponing a consultation if the loss of sensitivity recurs or is accompanied by weakness. At the medical center, patients can undergo an examination and the necessary tests so that the doctor can determine the possible cause of the symptoms and select the further treatment approach. 

The information in this article is provided for informational purposes and is not an instruction for self-diagnosis or self-treatment. If symptoms of a disease appear, you should consult a doctor.

Sources:

National Institute of Neurological Disorders and Stroke 

American Heart Association

National Institute for Health and Care Excellence