Short-term muscle weakness is common and can be caused by something as simple as a tough workout. However, persistent muscle weakness with no apparent cause could indicate an underlying health condition.
Muscle weakness happens when full effort doesn’t produce typical muscle contraction or movement.
Voluntary muscle contractions are usually generated when your brain sends signals through your spinal cord and nerves to a muscle.
If your brain, nervous system, muscles, or the connections between them are injured or affected by the disease, your muscles may not contract as they should. This can produce muscle weakness.
Many health conditions can cause muscle weakness.
Examples include:
- neuromuscular disorders, such as multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS)
- autoimmune diseases, such as myasthenia gravis and Guillain-Barré syndrome
- thyroid conditions, such as hypothyroidism and hyperthyroidism
- electrolyte imbalances, such as:
- hypokalemia (potassium deficiency)
- hypomagnesemia (magnesium deficiency)
- hypercalcemia (elevated calcium in your blood)
Other conditions that may cause muscle weakness include:
- stroke
- chronic fatigue syndrome (CFS)
- hypotonia, a lack of muscle tone that’s usually present at birth
- peripheral neuropathy, a type of nerve damage
- neuralgia, or sharp burning or pain following the path of one or more nerves.
- polymyositis, or chronic muscle inflammation
Muscle weakness can also be caused as a side effect of some medications, including:
- statins and other lipid-lowering agents
- antiarrhythmic drugs
- corticosteroids
If you experience muscle weakness that isn’t going away or is getting worse, consider speaking with a healthcare professional.
They will typically begin by asking about:
- your muscle weakness, including how long you’ve had it and which muscles have been affected
- any other symptoms you may be experiencing
- your family medical history
They may also check your reflexes and muscle tone.
If needed, they may order one or more tests, such as:
- CT scans or MRI to examine the inner structures of your body
- nerve tests to assess how well your nerves are working
- electromyography (EMG) to test the nerve activity in your muscles
- blood tests to help identify causes of muscle weakness
You can book an appointment with a primary care doctor in your area using our Healthline FindCare tool.
Once they’ve determined the cause of your muscle weakness, a healthcare professional will recommend appropriate treatment. Your treatment plan will depend on the underlying cause of your muscle weakness, as well as the severity of your symptoms.
Here are some of the treatment options for conditions that cause muscle weakness:
Physical therapy
Physical therapy involves exercises that can help improve your quality of life if you have conditions such as MS or ALS.
For example, a physical therapist might suggest progressive resistive exercise to help someone with MS strengthen muscles that have become weak from lack of use.
For someone with ALS, a physical therapist might recommend stretching and range of motion exercises to prevent muscle stiffness.
Occupational therapy
Occupational therapy includes exercises that focus on strengthening the upper body. Therapists can also recommend assistive devices and tools to help with daily activities.
Occupational therapy can be especially helpful during the stroke rehabilitation process. Therapists can recommend exercises to address weakness in one side of your body and help with motor skills.
Medication
Over-the-counter (OTC) pain relievers, such as ibuprofen or acetaminophen, may help manage pain associated with conditions such as:
- peripheral neuropathy
- CFS
- neuralgia
Thyroid hormone replacement is used to treat hypothyroidism. Standard treatment usually involves taking levothyroxine (Levoxyl, Synthroid), which is a synthetic thyroid hormone.
Dietary changes
Adjusting your diet can help remedy electrolyte imbalances. Depending on your needs, a healthcare professional may also suggest taking supplements, such as calcium, magnesium oxide, or potassium oxide.
Surgery
Surgery may be used to treat certain conditions, such as a herniated disc or hyperthyroidism.
In some cases, muscle weakness can be a sign of something very serious, such as a stroke.
If you experience any of the
- sudden onset of muscle weakness
- sudden numbness or loss of feeling
- sudden difficulty moving your limbs, walking, standing, or sitting upright
- sudden difficulty smiling or forming facial expressions
- sudden confusion, difficulty speaking, or trouble understanding things
- chest muscle weakness resulting in difficulties breathing
- loss of consciousness
Short-term muscle weakness is common and can be caused by something as simple as a tough workout.
However, it can also be caused by an underlying health condition, such as MS, an autoimmune condition, or an electrolyte imbalance.
To treat muscle weakness, you will need to address the root cause.
If you experience muscle weakness that doesn’t go away or gets worse, it’s important to speak with a healthcare professional.