Overview

Weakness and fatigue are two different things. It's important to know exactly what you mean when you talk with your doctor about how you're feeling. It can help you and your doctor narrow down the possible causes of your symptoms.

Weakness

Weakness is a lack of physical or muscle strength. You feel like you need to use extra effort to move your arms, legs, or other muscles.

General weakness often occurs after you've done too much activity at one time. For instance, maybe you took an extra-long hike. You may feel weak and tired, or your muscles may be sore. These symptoms usually go away within a few days.

In rare cases, muscle weakness may be caused by another health problem. These include:

• A problem with the minerals (electrolytes) found naturally in the body. Examples are low levels of potassium or sodium.
• Infections, such as a urinary tract infection or a respiratory infection.
• Problems with the thyroid gland. This gland regulates the way the body uses energy.
• Rare nerve disorders, such as Guillain-Barré syndrome.

Muscle weakness that is slowly getting worse needs to be checked by a doctor.

Sudden muscle weakness and loss of function in one area of the body also needs to be checked by a doctor right away. It can be a sign of a stroke or of a problem with the spinal cord or a nerve.

Fatigue

Fatigue is a feeling of tiredness, exhaustion, or lack of energy. You may feel mildly fatigued because of overwork, poor sleep, worry, boredom, or lack of exercise. Any illness may cause fatigue. It usually goes away as the illness clears up. Most of the time, mild fatigue occurs with a health problem that will improve with home treatment. It usually doesn't require a visit to a doctor.

Many medicines can cause weakness or fatigue. The use of alcohol, caffeine, or illegal drugs can cause fatigue.

Fatigue that lasts longer than 2 weeks usually requires a visit to a doctor. This type may be caused by a more serious health problem, such as:

• A decrease in the amount of the substance that carries oxygen in red blood cells (anemia).
• Problems with the heart, such as coronary artery disease or heart failure.
• Metabolic disorders, such as diabetes.
• Problems with the thyroid gland. It regulates the way the body uses energy.
• Kidney disease and liver disease.

Fatigue is a common symptom of mental health problems, such as anxiety or depression. If you think that your fatigue may be caused by a mental health problem, see your doctor.

Self-Care

If you have generalized weakness and fatigue along with other symptoms, look closely at those symptoms. Home treatment for your other symptoms usually will improve your weakness and fatigue. Mild generalized weakness and fatigue that occur with a viral illness usually improve with home treatment. Here are some things you can try.

• If you can, stay home when you are sick.

  Try to stay away from others and get some extra sleep.

• Go slowly.

  Return to your usual activities slowly to avoid making the fatigue last longer.

• Stay hydrated.

  Be sure to drink extra fluids to avoid dehydration.

• Listen to your body.

  Switch between rest and exercise. Gradually increasing your exercise may help decrease your fatigue.

• Limit medicines that might add to fatigue.

  Medicines like cold and allergy medicines often cause fatigue.

• Improve your diet.

  Eat a balanced diet to increase your energy level. Don't skip meals.

• Beware of substances that may cause fatigue.

  Reduce your use of alcohol or other drugs, such as caffeine or nicotine.

• Cut back on screen time.

  Spend that time with friends or try new activities to break the fatigue cycle.

• Get a good night's sleep.

  This may be the first step toward controlling fatigue.

  • Try to limit sound and light disturbances.
  • Avoid eating just before you go to bed.
  • Avoid using screens before you go to bed. Use your bed only for sleeping.

When to call for help during self-care

Call a doctor if any of the following occur during self-care at home:

• Symptoms occur more often or are more severe.

Preparing For Your Appointment