MSD Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Weakness

By

The Manual's Editorial Staff

Medically Reviewed Sep 2021 | Modified Sep 2022
VIEW PROFESSIONAL VERSION
Get the full details

What is weakness?

Weakness is a loss of muscle strength. If you have weakness, you can’t move a muscle normally, even when you’re trying as hard as you can. Weakness is different than being tired (fatigued Fatigue Fatigue is when a person feels a strong need to rest and has so little energy that starting and sustaining activity is difficult. Fatigue is normal after physical exertion, prolonged stress... read more ), having stiff muscles, or not being able to move part of your body because it hurts too much to move.

When should I see a doctor?

Go to the emergency department right away if you have muscle weakness and any of these warning signs:

  • Weakness that starts over a few days or faster

  • Trouble breathing

  • Trouble raising your head while lying down

  • Trouble chewing, talking, or swallowing

  • Being unable to walk

Call your doctor if you have muscle weakness without any warning signs so your doctor can decide how quickly to see you.

What causes weakness?

Weakness all over your body usually has different causes than weakness that's just in certain muscles.

If you have weakness all over your body, common causes are:

If you have weakness just in certain muscles, common causes are:

What will happen at my doctor visit?

Doctors will ask questions about your weakness. They’ll do a physical exam to check for problems with your brain, spinal cord, nerves, and muscles, and to make sure you’re breathing well.

Depending on what doctors think is causing your weakness, they may do tests (see Diagnosis of Brain, Spinal Cord, and Nerve Disorders Diagnosis of Brain, Spinal Cord, and Nerve Disorders ). These tests may include:

How do doctors treat weakness?

NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
VIEW PROFESSIONAL VERSION
quiz link

Test your knowledge

Take a Quiz! 
iOS ANDROID
iOS ANDROID
iOS ANDROID
TOP