CFS symptoms can make it hard to do everyday activity. They also differ among people. Symptoms may appear quickly or build slowly over time. They may also appear after an infection such as a cold. The infection goes away, but severe fatigue lingers. Symptoms can be constant or may come and go.

The main symptoms for CFS include:

  • Having a hard time meeting the activity level you had before you were sick. This includes work, school, social events, or exercise. It may worsen with time.
  • Physical or mental fatigue after which gets worse with exertion. Fatigue can last more than 24 hours.
  • Fatigue that doesn't get better with rest or a full night's sleep.
  • Problems falling or staying asleep, or the need to nap during the day.
  • Problems with short-term memory, concentration, or confusion can lead to problems with work and school. This is often called brain fog.
  • Lightheadedness or vision problems when standing or sitting up.

Other symptoms may include:

  • Muscle aches
  • Joint pain without swelling or redness
  • Long-lasting 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: Updated September 10, 2018. Accessed February 8, 2019.

Chronic fatigue syndrome. Merck Manual Professional Version website. Available at: Updated July 2018. Accessed February 8, 2019.

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 of ME/CFS. Centers for Disease Control and Prevention website. Available at: Updated July 12, 2018. Accessed February 8, 2019.

Yancey JR. Thomas SM. Chronic fatigue syndrome: diagnosis and treatment. Am Fam Physician. 2012;8(68):741-746.

Last reviewed December 2018 by EBSCO Medical Review Board Marcin Chwistek, MD  Last Updated: 2/8/2019