Asthenia, also known as weakness, is the feeling of body fatigue or tiredness. A person experiencing weakness may not be able to move a certain part of their body properly. Asthenia is best described as a lack of energy to move certain muscles or even all muscles in the body.

Some people experience asthenia in a certain area of their body, such as the arms or legs. Others may experience full-body weakness, which is often the result of a bacterial or viral infection such as influenza or hepatitis.

Weakness may be temporary, but it’s chronic or continuous in some cases.

Common causes of weakness include:

Other causes of weakness include:

  • cancer
  • stroke
  • heart attack
  • nerve or muscle injuries
  • diseases affecting the nerves or muscles
  • medication overdose
  • vitamin overdose
  • poison

Although weakness caused by cancer may appear slowly over an extended amount of time, weakness caused by a heart attack or stroke often occurs immediately.

In addition to experiencing weakness, other symptoms such as difficulty breathing, pain, and irregular heartbeat may occur. Call 911 if you experience sudden weakness. Don’t try to drive yourself to the hospital.

Isolated weakness

If you feel weak in one area of your body, you may find that you can’t move that part of your body efficiently. You may also experience:

Full-body weakness

Full-body weakness causes you to feel run down, similar to the feeling you get when you have the flu. This is known as fatigue, but it’s also possible to experience full-body weakness without feeling tired.

Some people who experience full-body weakness also experience:

  • fever
  • flu-like symptoms
  • pain in the affected area

Emergency symptoms

You should contact your doctor if you experience any of the following symptoms:

  • dizziness
  • lightheadedness
  • confusion
  • difficulty speaking
  • changes in vision
  • chest pain
  • difficulty breathing

There are many treatment options for weakness. Determining the underlying cause helps your doctor determine the best treatment method.

When you visit your doctor, they’ll go over your symptoms. They’ll ask you when you began experiencing symptoms. This will help your doctor better understand what may be causing you to feel weak.

Your doctor may request that you give a urine sample. They may also request a blood sample and send it to a lab for testing. The lab will test these samples for signs of infection and possible medical conditions that may cause weakness.

If you’re experiencing pain, your doctor may also order an imaging test to have a look at the area. Imaging tests may include:

Your doctor will order a brain scan and electrocardiogram if they suspect you’re having or have had a heart attack or stroke.

Once your doctor diagnoses the cause of your weakness, they’ll discuss treatment options with you based on their diagnosis.

Here are some common causes and their respective treatments:


If you’re dehydrated, increasing your fluid intake can help. However, if you’re showing severe symptoms of dehydration, you may require hospital treatment.

At the hospital, you’ll receive fluids through an intravenous (IV) line. You may also need medication to increase your blood pressure. At this point, the weakness may begin to subside.


If your weakness is due to anemia, you may need iron supplementation if it appears that you’re iron deficient.

You may need a blood transfusion if your anemia is severe. If you need a blood transfusion, you’ll receive one in the hospital. This treatment consists of receiving donor blood through an IV line.


If cancer is the cause of your weakness, your doctor will discuss your treatment options. The stage, location, and body structure involved all help to determine the best course of treatment. Treatment options for cancer include:

Chemotherapy and other cancer treatments can also cause asthenia.

Heart attack

If a heart attack caused your weakness, your doctor will discuss treatment options with you.

Not all cases of weakness require treatment. If your weakness is due to a cold or the flu, treatment may not be necessary.

Some of the causes of weakness are part of a normal life. For example, if you have weakness due to a cold, time and rest should eventually clear up your weakness.

If your weakness originates from a more serious condition, seeing your doctor early and regularly can help you recover more quickly.

Taking care of your physical health is a good preventive measure. Drinking plenty of fluids, getting adequate rest, and exercising regularly can help your recover from weakness and also prevent it.