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.
Muscle weakness may happen suddenly or little by little over time
You may have weakness all over your body or just in certain muscles
Weakness can be dangerous if it involves the muscles that control your breathing
Physical Physical Therapy (PT) Physical therapy, a component of rehabilitation, involves exercising and manipulating the body with an emphasis on the back, upper arms, and legs. It can improve joint and muscle function, helping... read more and occupational Occupational Therapy (OT) Occupational therapy, a component of rehabilitation, is intended to enhance a person's ability to do basic self-care activities, useful work, and leisure activities. These activities include... read more therapy can often help your muscles get stronger depending on what’s causing the weakness
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 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:
Worsened physical fitness, especially if you’re over 55
Losing muscle strength after being on bed rest
Problems with nerves all over the body that control your muscles
Muscle problems that can happen from low potassium Hypokalemia (Low Level of Potassium in the Blood) In hypokalemia, the level of potassium in blood is too low. A low potassium level has many causes but usually results from vomiting, diarrhea, adrenal gland disorders, or use of diuretics. A... read more , taking corticosteroids, or drinking too much alcohol Alcohol Alcohol (ethanol) is a depressant. Consuming large amounts rapidly or regularly can cause health problems, including organ damage, coma, and death. Genetics and personal characteristics may... read more
Certain medicines, such as drugs that doctors use during surgery to keep you from moving
If you have weakness just in certain muscles, common causes are:
Stroke Stroke A stroke is a sudden brain problem that happens when a blood vessel in your brain either gets blocked or breaks open and bleeds. Part of your brain stops getting blood. Brain tissue that doesn't... read more (especially if your weakness is on one side of your body)
Nerve damage from injuries
A ruptured disk in your spine
Pressure on your spinal cord from severe arthritis, infection, or cancer that has spread to your spinal cord
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 read more ). These tests may include:
MRI Magnetic Resonance Imaging (MRI) MRI is a test that uses a machine with a powerful magnet to make pictures of the inside of your body. A computer records changes in the magnetic field around your body. The computer then uses... read more or CT scan Computed Tomography A CT scan uses a large machine shaped like a large donut to take x-rays from many angles. A computer then takes the x-rays and creates many detailed pictures of the inside of your body. Each... read more to see pictures of the inside of your body
Electromyography and nerve conduction studies Electromyography and Nerve Conduction Studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more to measure electrical activity in your nerves and muscles
Blood and urine tests
How do doctors treat weakness?
Doctors will treat the cause of your muscle weakness
If you have trouble breathing because of weakness in the muscles needed to breathe, they may put you on a breathing machine
They may have you get physical therapy Physical Therapy (PT) Physical therapy, a component of rehabilitation, involves exercising and manipulating the body with an emphasis on the back, upper arms, and legs. It can improve joint and muscle function, helping... read more to help strengthen your muscles and occupational therapy Occupational Therapy (OT) Occupational therapy, a component of rehabilitation, is intended to enhance a person's ability to do basic self-care activities, useful work, and leisure activities. These activities include... read more to help you learn new ways to do daily activities