Fatigue

Fatigue: Common Causes

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

• Anemia (including iron deficiency anemia)
• Sleep disorders like ongoing insomnia, obstructive sleep apnea, or narcolepsy
• Ongoing pain
• An allergy that leads to hay fever or asthma
• An underactive thyroid (hypothyroidism)
• Use of alcohol or illegal drugs like cocaine, especially with regular use
• Depression or grief

Fatigue can also accompany the following illnesses:

• Infection, especially one that takes a long time to recover from or treat, like bacterial endocarditis (infection of the heart muscle or valves), parasitic infections, AIDS, tuberculosis, and mononucleosis
• Congestive heart failure
• Diabetes
• Chronic liver or kidney disease
• Addison's disease
• Anorexia or other eating disorders
• Arthritis, including juvenile rheumatoid arthritis, which affects children and teens
• Autoimmune diseases such as lupus
• Malnutrition
• Cancer

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.