Medical Encyclopedia


Medical Encyclopedia

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Contents of this page:

Alternative Names   

Tiredness; Weariness; Exhaustion; Lethargy

Definition    Return to top

Fatigue is a feeling of weariness, tiredness, or lack of energy.

Considerations    Return to top

Fatigue is different from drowsiness. In general, drowsiness is feeling the need to sleep, while fatigue is a lack of energy and motivation. Drowsiness and apathy (a feeling of indifference or not caring about what happens) can be symptoms of fatigue.

Fatigue can be a normal and important response to physical exertion, emotional stress, boredom, or lack of sleep. However, it can also be a nonspecific sign of a more serious psychological or physical disorder. When fatigue is not relieved by enough sleep, good nutrition, or a low-stress environment, it should be evaluated by your doctor. Because fatigue is a common complaint, sometimes a potentially serious cause may be overlooked.

The pattern of fatigue may help your doctor determine its underlying cause. For example, if you wake up in the morning rested but rapidly develop fatigue with activity, you may have an ongoing physical condition like an underactive thyroid. On the other hand, if you wake up with a low level of energy and have fatigue that lasts throughout the day, you may be depressed.

Causes    Return to top

There are many possible physical and psychological causes of fatigue. Some of the more common are:

Fatigue can also accompany the following illnesses:

Certain medications may also cause drowsiness or fatigue, including antihistamines for allergies, blood pressure medicines, sleeping pills, steroids, and diuretics.

Chronic fatigue syndrome (CFS) is a condition that starts with flu-like symptoms and lasts for 6 months or more. All other possible causes of fatigue are eliminated before this diagnosis is made. Little relieves CFS, including rest.

Home Care    Return to top

Here are some tips for reducing fatigue:

If you have chronic pain or depression, treating either often helps address the fatigue. However, some antidepressant medications may cause or worsen fatigue. Your medication may have to be adjusted to avoid this problem. DO NOT stop or change any medications without instruction from your doctor.

Stimulants (including caffeine) are NOT effective treatments for fatigue, and can actually make the problem worse when the drugs are stopped. Sedatives also tend to worsen fatigue in the long run.

When to Contact a Medical Professional    Return to top

Call your doctor right away if:

Call your doctor if:

What to Expect at Your Office Visit    Return to top

Your doctor will obtain your medical history and perform a complete physical examination, with special attention to your heart, lymph nodes, and thyroid. He or she may ask questions about your lifestyle, habits, and feelings.

Questions may include:

Diagnostic tests that may be performed include the following:

References    Return to top

Ressel GW. National Institutes of Health. NIH releases statement on managing pain, depression, and fatigue in cancer. Am Fam Physician. 2003; 67(2): 423-424.

Penninx BW. Anemia and decline in physical performance among older persons. Am J Med. 2003; 115(2): 104-110.

Williams RH, Larsen PR, eds. Williams Textbook of Endocrinology. Amsterdam, Netherlands: Elsevier; 2003.

Gonzalez R. Common Syndromes. In McPhee SJ, Papadakis MA, and Tierney, Jr. LM, eds. Current Medical Diagnosis & Treatment 2007. New York: McGraw-Hill; 2007.

Bennett B, Goldstein D, Friedlanger M, Hickie I, Lloyd A. The experience of cancer-related fatigue and chronic fatigue syndrome: a qualitative and comparative study. J Pain Symptom Manage. 2007; May e-pub.

Update Date: 7/17/2007

Updated by: Robert Hurd, MD, Professor of Endocrinology, Department of Biology, Xavier University, Cincinnati, OH, and physician in the Primary Care Clinic, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio. Review provided by VeriMed Healthcare Network.

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