Weakness in Legs: Common Causes & When to Worry

Weakness in legs is a common symptom that can happen after intense physical activity or due to issues like poor circulation. In many cases, it is temporary and improves on its own within a short period.

However, weakness in legs that persists or worsens over time may be linked to more serious conditions, such as peripheral neuropathy, herniated disc, or even stroke. These conditions often cause other symptoms like numbness, dizziness, pain, or difficulty moving.

When weakness in legs interferes with daily activities or appears alongside other symptoms, medical evaluation is important to identify the cause. Treatment may include rest, physical therapy, medication, or urgent care depending on the underlying condition.

Main causes

Weakness in the legs may be the result of: 

1. Intense physical activity

One of the most common causes of temporary leg weakness is physical exercise. It is especially noticeable in people who do not exercise regularly. This weakness usually occurs right after working out and typically improves within a few minutes.

In the following days, it is possible to experience weakness again. You may notice muscle pain, which is a sign of muscle wear and tear. This usually resolves on its own after 2 to 3 days. 

What to do: In most cases, you will be advised to rest and gently massage the affected leg muscles to help relieve discomfort and support recovery. If you have intense weakness or severe pain, you should be evaluated by a healthcare provider, who may prescribe an anti-inflammatory medicine.

2. Poor circulation

Another relatively common cause of leg weakness is poor circulation. It is more likely to affect people over age 50 and those who spend long periods of time standing. Read about what can cause poor circulation in the legs.

In addition to weakness in the legs, poor circulation can also lead to other symptoms like cold feet, swelling in the legs and feet, dry skin, and varicose veins. 

What to do: One way to improve leg circulation is to wear compression stockings during the day, especially if you know you will be standing for a long time. You should elevate your legs at the end of your day and engage in regular physical activity, such as walking. Learn more about how to improve circulation.

3. Peripheral neuropathy

Peripheral neuropathy occurs when the peripheral nerves, which carry information between the brain, spinal cord, and the rest of the body, are damaged. When this happens, symptoms may include weakness in the arms and legs, tingling, and persistent pain.

In most cases, peripheral neuropathy develops as a complication of poorly controlled diabetes (diabetic neuropathy), but it can also occur after exposure to certain toxic substances or following some infections.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), diabetes is the most common cause of neuropathy, and long‑term high blood glucose can damage nerves and the small blood vessels that supply them.

What to do: Treatment focuses on addressing the underlying cause of the nerve damage. In some cases, following a strict medication regimen may be needed to control symptoms and improve quality of life.

4. Herniated disc

A herniated disc occurs when an intervertebral disc bulges or leaks out of its normal space in the spine. It can cause leg weakness and back pain that spreads to the buttocks or legs. Other symptoms may include difficulty moving and numbness, burning, or tingling in the back, buttocks, or legs.

What to do: Treatment may involve medication, physical therapy, or even surgery, depending on severity. 

5. Stroke

A stroke happens when blood flow to part of the brain is suddenly interrupted. According to the CDC, stroke can cause sudden weakness or numbness in the face, arm, or leg, especially on one side of the body, along with symptoms such as dizziness, confusion, or trouble speaking.

Read more about stroke symptoms and how to recognize when one is happening.

What to do: A stroke is life-threatening and requires urgent treatment. If it is not treated, it can lead to serious complications, such as difficulty speaking or moving.

To help prevent a stroke, it is important to follow a healthy, balanced diet, exercise regularly, and manage conditions such as high blood pressure, high cholesterol, high triglycerides, and diabetes.

6. Guillain-Barré syndrome

Guillain-Barré syndrome is a serious autoimmune disorder in which the immune system attacks the body’s own peripheral nerves. This causes nerve inflammation that can lead to weakness in the arms and legs and, in severe cases, paralysis that may be life-threatening.

What to do: Treatment is provided in a hospital and may involve a procedure called plasmapheresis. In this procedure, blood is removed from the body, filtered to remove harmful substances, and then returned.

A second part of treatment often includes high-dose immunoglobulin given by injection to help destroy antibodies that are causing nerve damage and inflammation.

7. Multiple sclerosis

Multiple sclerosis is a chronic autoimmune disease in which the immune system attacks the myelin sheath that covers nerve cells. Damage to this myelin coating disrupts normal nerve signaling and can impair how nerve cells function.

Symptoms can include arm or leg weakness, difficulty walking, problems with coordination, incontinence, memory loss, trouble concentrating, and vision changes.

What to do: Treatment for multiple sclerosis usually includes medication and physical therapy to help manage specific symptoms. Treatment plans can vary widely from person to person.

Other conditions that can cause leg weakness include Parkinson’s disease, myasthenia gravis, and spine injuries.

8. Cauda equina syndrome

Cauda equina syndrome occurs when the nerves in the lower part of the spinal canal are compressed, especially those that control the bladder, bowels, sexual function, and lower limbs.

It is characterized by symptoms such as decreased sensation in the saddle area (inner thighs, buttocks, and genitals) and muscle weakness in the legs. It can result from a herniated lumbar disc, infections, fractures, or tumors.

What to do: Cauda equina syndrome requires emergency surgery because serious complications can develop if it is not treated promptly.

9. Transverse myelitis

Transverse myelitis is an inflammation of the spinal cord that can be triggered by an autoimmune disorder or by a viral or bacterial infection. It can cause symptoms such as back pain, muscle weakness, decreased sensation, and muscle paralysis, including weakness or paralysis of the legs or arms.

What to do: Treatment for transverse myelitis varies by case, but it usually includes medications to prevent or treat infections, reduce spinal cord swelling, and relieve symptoms. The main goal of treatment is to improve the person’s quality of life.

10. Lyme disease

Lyme disease is an infection caused by the bite of an infected tick. It can cause a skin rash and redness, fatigue, muscle pain and weakness (including in the legs), joint pain, headache, fever, and chills.

What to do: Lyme disease is treated with antibiotics such as doxycycline.