Chronic Fatigue Syndrome (CFS) Overview
Chronic fatigue syndrome (CFS) is a chronic, debilitating disorder. It affects your brain and multiple parts of your body. It causes extreme fatigue and is not relieved by bed rest. Physical or mental fatigue often makes the condition worse. Symptoms last at least six months and are severe enough to interfere with daily activities.
There is no specific lab test or clinical sign for CFS. No one knows exactly how many people are affected by this illness. The Centers for Disease Control and Prevention estimates, that as many as 500,000 people in the US have a CFS-like condition.
No one knows what causes CFS. For more than a century, doctors have reported seeing illnesses similar to it. In the 1860s, Dr. George Beard named the syndrome neurasthenia. He thought it was a nervous disorder with weakness and fatigue. Experiments in men supported his idea that the brain is somehow involved in CFS.
In the early 1980s, CFS was stereotyped as a new yuppie flu. People who sought help for their symptoms were primarily upper middle-class women in their thirties and forties. Since then, health experts have suggested other explanations for this baffling illness, including:
- Various viruses (such as, Epstein-Barr virus, enteroviruses, parvovirus B19 , Coxiella burnetii, Chlamydia pneumoniae)
- Malfunction of the hypothalamic-pituitary-adrenal axis
- Emotional stress
- Iron-poor blood (anemia)
- Low blood sugar (hypoglycemia)
- Low blood pressure
- Environmental allergy or toxins
- Body-wide yeast infection (candidiasis)
- Adrenal Fatigue
Doctors now report seeing the syndrome in people of all ages, races, and social and economic classes. It is also found in several countries around the world. Women are still more affected than men about 4:1.
Recovery time varies among individuals with Chronic Fatigue Syndrome. You may recover to the point where you can resume work and other activities. You may continue to experience various or periodic CFS symptoms. CFS typically follows a cyclical course. It alternates between periods of illness and relative well-being. You may also recover completely with time.
What are the treatments for chronic fatigue syndrome?
What is it like to live with chronic fatigue syndrome?
Centers for Disease Control and Prevention website. Available at:
Devanur LD, Kerr JR. Chronic fatigue syndrome.
J Clin Virol.2006;37:139-150.
Prins JB, van der Meer JW, Bleijenberg G. Chronic fatigue syndrome.
National Institute of Allergy and Infectious Diseases website. Available at: