Chronic fatigue syndrome Symptoms and causes Mayo Clinic Chronic fatigue syndrome CFS is a complicated disorder characterized by extreme fatigue that can t be explained by any underlying medical condition The fatigue may worsen with physical or mental activity, but doesn t improve with rest. Chronic Fatigue Syndrome CFS Center Symptoms, Causes Chronic Fatigue Syndrome Chronic fatigue syndrome, or CFS, causes you to feel so tired that you can t complete normal, daily activities While chronic fatigue syndrome has no known cause and is Chronic Fatigue Syndrome CFS MedlinePlus Chronic fatigue syndrome CFS is a serious, long term illness that affects many body systems Another name for it is myalgic encephalomyelitis chronic fatigue syndrome ME CFS CFS can often make you unable to do your usual activities. Chronic fatigue syndrome Chronic fatigue syndrome CFS , also referred to as myalgic encephalomyelitis ME , is a medical condition characterized by long term fatigue and other long term symptoms that limit a person s ability to carry out ordinary daily activities. Chronic Fatigue Syndrome Causes, Symptoms, and Treatment Chronic fatigue syndrome CFS is a debilitating disorder characterized by extreme fatigue or tiredness that doesn t go away with rest and can t be explained by an underlying medical condition. Chronic Fatigue Syndrome CFS Symptoms and Causes Chronic fatigue syndrome is than feeling tired all the time It comes with a lot of other symptoms that can make it hard to handle daily life Even simple things like walking to the mailbox Chronic Fatigue Syndrome Symptoms, Treatment Tests Chronic fatigue syndrome also called CFS is a disorder without a known cause, although CFS may be related to a previous infection CFS is a state of chronic fatigue that exists without other explanation for six months or and is accompanied by cognitive difficulties problems with short term memory or concentration You may have CFS if you meet the following criteria Myalgic Encephalomyelitis Chronic Fatigue Syndrome ME CFS Myalgic encephalomyelitis chronic fatigue syndrome ME CFS is a serious, long term illness that affects many body systems People with ME CFS are often not able to do their usual activities Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content. Chronic fatigue syndrome Diagnosis and treatment Mayo Sleep disorders Chronic fatigue can be caused by sleep disorders A sleep study can determine if your rest is being disturbed by disorders such as obstructive sleep apnea, restless legs syndrome Chronic Fatigue Syndrome CFS or Systemic Exertion Chronic fatigue is a symptom of many illnesses, so chronic fatigue syndrome had to have criteria that distinguished it from similar medical conditions that have chronic fatigue as a major symptom for example, fibromyalgia, chronic mononucleosis, neurologic problems, Lyme disease, and sensitivity to certain chemicals.