Chronic Fatigue Syndrome (cont.)

Prevalence of CFS

Chronic fatigue syndrome (CFS) affects more than one million people in the United States. There are tens of millions of people with similar fatiguing illnesses who do not fully meet the strict research definition of CFS.

Risk Factors for CFS

  • People of every age, gender, ethnicity and socioeconomic group can have CFS.


  • CFS affects women at four times the rate of men.


  • Research indicates that CFS is most common in people in their 40s and 50s.


  • Although CFS is much less common in children than in adults, children can develop the illness, particularly during the teen years.

Defining CFS Symptoms

  • CFS is marked by extreme fatigue that has lasted at least six months; is not the result of ongoing effort; is not substantially relieved by rest; and causes a substantial reduction in daily activities.


  • In addition to fatigue, CFS includes eight characteristic symptoms:


    • postexertional malaise (relapse of symptoms after physical or mental exertion);


    • unrefreshing sleep;


    • substantial impairment in memory/concentration;


    • muscle pain;


    • pain in multiple joints;


    • headaches of a new type, pattern or severity;


    • sore throat;


    • and tender neck or armpit lymph nodes.


  • Symptoms and their consequences can be severe. CFS can be as disabling as multiple sclerosis, lupus, rheumatoid arthritis, congestive heart failure and similar chronic conditions. Symptom severity varies from patient to patient and may vary over time for an individual patient.