Fatigue is a feeling of weariness, tiredness, or lack of energy.
Fatigue is different from drowsiness. Drowsiness is feeling the need to sleep. Fatigue is a lack of energy and motivation. Drowsiness and apathy (a feeling of not caring about what happens) can be symptoms that go along with fatigue.
Fatigue can be a normal and important response to physical activity, emotional stress, boredom, or lack of sleep. Fatigue is a common symptom, and it is usually not due to a serious disease. But it can be a sign of a more serious mental or physical condition. When fatigue is not relieved by enough sleep, good nutrition, or a low-stress environment, it should be evaluated by your doctor.
The pattern of fatigue may help your doctor determine its cause. For example, if you wake up in the morning rested but quickly develop fatigue with activity, you may have a condition such as 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.
There are many possible causes of fatigue, including:
Fatigue can also occur with 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. It is diagnosed based on the presence of a specific group of symptoms and after all other possible causes of fatigue are ruled out. Most people with CFS do not get much relief from rest.
Here are some tips for reducing fatigue:
If you have chronic pain or depression, treating it often helps the fatigue. But 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 first talking to your doctor.
Stimulants (including caffeine) are not effective treatments for fatigue. They can make the problem worse when they are stopped. Sedatives also tend to worsen fatigue.
Call your doctor right away if:
Call your doctor if:
Your doctor will perform a complete physical examination, paying special attention to your heart, lymph nodes, thyroid, abdomen, and nervous system. You will be asked about your medical history, symptoms, and your lifestyle, habits, and feelings.
Questions may include:
Tests that may be ordered include the following:
Tiredness; Weariness; Exhaustion; Lethargy
Bennett RM. Fibromyalgia and chronic fatigue syndrome. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, Pa.: Elsevier Saunders; 2011:chap 282.
Griggs RC, Jozefowicz RF, Aminoff MJ. Approach to the patient with neurologic disease. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, Pa.: Elsevier Saunders; 2011:chap 403.
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.
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