Symptoms of Chronic Fatigue Syndrome (CFS)

CFS symptoms usually appear suddenly, but for some people they may develop over a longer period of time. This may happen after an infection such as a cold. Even though the infection goes away, many have persistent, severe fatigue that interferes with normal function. CFS symptoms vary from person to person, and may come and go in cycles of symptom remission and flare-ups.

The main symptoms for CFS include:

  • Decreased ability to maintain normal activity experienced before the onset of illness. Activities include work, school, socializing, or exercising.
  • Postexertional malaise—Physical or mental fatigue that gets worse after exertion and can last more than 24 hours.
  • Fatigue that's not resolved with adequate rest or a full night's sleep.
  • Sleep problems such as difficulty falling or staying asleep, or the need to nap.
  • Trouble with short-term memory or concentration, forgetfulness, or confusion—Often described as brain fog and may cause problems with work or school.
  • Lightheadedness or vision problems when standing or sitting up.

Other symptoms may not be present in everyone, but may include:

  • Muscle aches
  • Joint pain without swelling or redness
  • Chronic pain
  • Headaches
  • Frequent sore throat
  • Tender lymph nodes
  • Mood swings
  • Chills and night sweats
  • Depression
  • Anxiety
  • Irritable bowel syndrome
  • Allergies
  • Sensitivity to many chemicals, noise, or food


Chronic fatigue syndrome. EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated August 30, 2018. Accessed May 4, 2018.
Chronic fatigue syndrome. Merck Manual Professional Version website. Available at: Updated October 2016. Accessed May 4, 2018.
Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, Board on the Health of Select Populations, Institute of Medicine. Beyond myalgic encephalomyelitis/chronic fatigue syndrome: redefining an illness. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington (DC): National Academies Press (US); 2015 Feb 10. Available at:
Symptoms. Centers for Disease Control and Prevention website. Available at: Updated July 4, 2017. Accessed May 4, 2018.
Yancey JR. Thomas SM. Chronic fatigue syndrome: diagnosis and treatment. Am Fam Physician. 2012;8(68):741-746.
Last reviewed May 2017 by EBSCO Medical Review Board James P. Cornell, MD
Last Updated: 5/4/2018


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