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:
- Anemia (including iron deficiency anemia)
- Depression or grief
- Iron deficiency (without anemia)
- Medications such as sedatives or antidepressants
- Persistent pain
- Sleep disorders such as insomnia, obstructive sleep apnea, or narcolepsy
- Thyroid gland that is underactive or overactive
- Use of alcohol or drugs such as cocaine or narcotics, especially with regular use
Fatigue can also occur with the following illnesses:
- Addison disease
- Anorexia nervosa or other eating disorders
- Arthritis, including juvenile rheumatoid arthritis
- Autoimmune diseases such as systemic lupus erythematosus
- Congestive heart failure
- Infection, especially one that takes a long time to recover from or treat, such as bacterial endocarditis (infection of the heart muscle or valves), parasitic infections, hepatitis, human immunodeficiency virus (HIV) AIDS, tuberculosis, and mononucleosis
- Kidney disease
- Liver disease
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:
- Get enough sleep each night.
- Eat a healthy, well-balanced diet and drink plenty of water throughout the day.
- Exercise regularly.
- Learn better ways to relax. Try yoga or meditation.
- Maintain a reasonable work and personal schedule.
- Change or reduce your stressors, if possible. For example, take a vacation or resolve relationship problems.
- Take a multivitamin. Talk to your doctor about what is best for you.
- Avoid alcohol, nicotine, and drug use.
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.
When to Contact a Medical Professional
Call your doctor right away if:
- You are confused or dizzy
- You have blurred vision
- You have little or no urine, or recent swelling and weight gain
- You have thoughts of harming yourself or of committing suicide
Call your doctor if:
- You have unexplained weakness or fatigue, especially if you also have a fever or unintentional weight loss
- You have constipation, dry skin, weight gain, or you cannot tolerate cold
- You wake up and fall back to sleep many times during the night
- You have headaches
- You are taking any medications, prescription or non-prescription, or using drugs that may cause fatigue or drowsiness
- You feel sad or depressed
- You have insomnia
What to Expect at Your Office Visit
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:
- How long have you had fatigue? Did it develop recently or awhile ago?
- Have you had fatigue in the past? If so, does it tend to occur in regular cycles?
- How many hours do you sleep each night?
- Do you have trouble falling asleep? Do you wake up during the night?
- Do you wake up in the morning feeling rested or fatigued?
- Do you snore or does someone who sleeps nearby tell you that you snore?
- Has anyone noticed that you stop breathing for short periods of time during sleep?
- Do you feel fatigued or tired throughout the day? Does it tend to get worse as the day goes on or stay about the same?
- Do you feel bored, stressed, unhappy, or disappointed?
- How are your relationships?
- Has anyone in your life recently passed away?
- Have you had more activity (mental or physical) lately?
- What is your diet like?
- Do you get regular exercise?
- Do you have any other symptoms like pain, headaches, or nausea?
- Have you had any recent change in appetite (up or down) or weight (up or down)?
- Do you take any prescription or non-prescription medications? Which ones?
Tests that may be ordered include the following:
- Blood tests to check for anemia, diabetes, inflammatory diseases, and possible infection
- Kidney function tests
- Liver function tests
- Thyroid function tests
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.
Update Date 4/21/2013
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.