Patient education: Weakness (The Basics)

What is weakness? — "Weakness" usually refers to a lack of muscle strength. Sometimes, people have weakness in just 1 part of the body, like an arm or a leg. Sometimes, the weakness extends to multiple parts of the body.

"Generalized" weakness is when you feel weak all over. Sometimes, people feel weak when they are tired or don't have enough energy, but their muscle strength is not affected.

What can cause weakness? — Different things can cause muscle weakness.

Less serious causes might include:

●Working your muscles too hard

●Temporary nerve compression, or when your arm or leg "falls asleep"

More serious causes of muscle weakness might include:

●Diseases that affect muscles or nerves – Examples include muscular dystrophy, Guillain-Barre syndrome, myasthenia, amyotrophic lateral sclerosis, and diabetes.

●Brain or spinal cord problems – Examples include stroke, multiple sclerosis, tumor, and infections.

Causes of generalized weakness are more varied. They can include stress, poor sleep, anemia, and certain medicines or medical conditions.

Will I need tests? — Maybe. Your doctor or nurse will ask about your symptoms and do an exam. They will check your muscle strength to find out if you have:

●Muscle tenderness

●Weakness in just 1 part of your body, 1 side of your body, or throughout your whole body

●The same muscle strength on both sides of your body

●Weakness in a specific pattern, such as worse after activity but gets better with rest

Your doctor or nurse might also do:

●Blood or urine tests

●Nerve conduction studies – These can show whether the nerves are carrying electrical signals the right way. In people with some causes of weakness, signals can be slow or weak.

●Electromyography ("EMG") – This test can show whether the muscles are responding the right way to electrical signals.

●MRI scan of your brain or spine – An MRI is an imaging test that creates pictures of the inside of your body.

●Muscle biopsy – The doctor takes a small sample of the weak muscle. Then, another doctor looks at the sample under a microscope.

How is weakness treated? — Treatment for weakness depends on what is causing it. If the weakness is caused by other more serious conditions or problems, the doctor or nurse will treat that condition. Physical therapy might be helpful in some cases.

Is there anything I can do on my own to feel better? — It might help to:

●Avoid alcohol and recreational drugs.

●Try to get regular physical activity. Even gentle forms of exercise, like walking, are good for your health.

●Try to get at least 8 hours of sleep every night. If you have trouble sleeping, you can do things to improve your sleep habits. For example, you can:

•Avoid drinking alcohol or caffeine in the late afternoon or evening.

•Try to go to bed and wake up at the same time every day.

•Limit your naps during the day, and don't nap for more than 30 minutes at a time.

●Try to eat a healthy diet that includes plenty of fruits, vegetables, whole grains, and low-fat dairy products. This can help improve your overall health.

●Try to avoid falls at home. If you were given a cane or walker, follow the instructions for using it.

What follow-up care do I need? — Your doctor or nurse will tell you if you need to make a follow-up appointment. If so, make sure that you know when and where to go.

When should I call the doctor? — Call for emergency help right away (in the US and Canada, call 9-1-1) if:

●You have signs of a stroke like:

•Sudden numbness or weakness of the face, arm, or leg, especially on 1 side of the body

•Sudden confusion, or trouble speaking or understanding

•Sudden trouble seeing in 1 or both eyes

•Sudden trouble walking, dizziness, or loss of balance or coordination

•Sudden severe headache with no known cause

●You have other signs of severe illness, or your weakness becomes severe, such as:

•You have a fever of 102.2°F (39° C) or higher, shaking chills, or sweats.

•You have trouble walking or lifting things, or feel so weak that you cannot get out of bed.

•You develop severe trouble breathing or severe chest discomfort.

•You become unresponsive.

Call for advice if:

●You feel like your heart is beating very fast or slow.

●You become dizzy or weak when standing up from a lying or sitting position.

●Your weakness gets worse, or you develop new problems such as slurred speech or double vision.

●You have problems eating or sleeping.

●You are having trouble functioning at work, at home, or in school.

More on this topic

Patient education: Muscular dystrophy (The Basics)
Patient education: Myasthenia gravis (The Basics)
Patient education: Guillain-Barré syndrome (The Basics)
Patient education: Multiple sclerosis in adults (The Basics)
Patient education: Multiple sclerosis in children (The Basics)
Patient education: Stroke (The Basics)
Patient education: Recovery after stroke (The Basics)
Patient education: Poliomyelitis (The Basics)
Patient education: Amyotrophic lateral sclerosis (ALS) (The Basics)

Patient education: Overview of muscular dystrophies (Beyond the Basics)
Patient education: Ischemic stroke treatment (Beyond the Basics)
Patient education: Hemorrhagic stroke treatment (Beyond the Basics)