Chronic fatigue syndrome (CFS) is a challenging condition for the people who have it and the medical professionals and researchers who are trying to understand it. CFS, also known as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), is an illness with an uncertain cause that frequently causes serious disability. According to the Institute of Medicine, approximately 836,000 to 2.5 million Americans live with ME/CFS. Up to 84% to 91% of people who meet the diagnostic criteria are not yet diagnosed.1
Many people find medical conditions without objective findings even more challenging to deal with. A person with this condition can be managing debilitating symptoms that are not visible to others.
Many people with this condition, more commonly women than men, describe it as bone-deep, unrelenting fatigue that does not improve with sleep. The symptoms can worsen with physical or mental activity, which makes working, engaging in family life, and attending to activities of daily living difficult.
Chronic fatigue syndrome is a serious, chronic disease that affects many body systems, causing symptom constellations that vary from person to person. Researchers have identified physiologic changes in the nervous, endocrine, and immune systems and changes in energy metabolism but have not yet identified a clear understanding of how these changes cause disease.2,3
There have been many definitions for ME/CFS, and they have evolved over time.2 The Institute of Medicine (National Academy of Sciences) proposed the following diagnostic criteria for ME/CFS:
ME/CFS is more common in women than in men. It can affect people of any age but is more common in people aged 40 to 60.
People may experience ME/CFS slightly differently, and their symptoms may come and go. However, some symptoms are more consistently found, including the following:
Chronic fatigue syndrome causes an overwhelming sense of fatigue that does not improve with sleep, exercise intolerance, and fatigue with mental effort. Chronic fatigue syndrome typically has an abrupt start. Previously healthy people experience a sudden change in their health.
Natural energy loss is normal fatigue that may be associated with increased exercise, lack of sleep, medication use, aging, weight changes, and chronic disease. Most people with natural energy loss are able to go about their day and meet their family, social and work obligations (though it may be challenging).
Unlike people with MF/CFS, people with natural energy loss can usually come up with solutions to improve their energy and motivation.
Here are some common causes of natural energy loss and ways to reduce fatigue associated with it.
Many people who meet the definition of MF/CFS remain undiagnosed. While MF/CFS does not have a specific diagnostic lab test or biomarker, the constellation of symptoms provides evidence of the condition. MF/CFS symptoms overlap with many other conditions. See your doctor to rule out some of these more easily diagnosed conditions and for guidance on how to best manage your MF/CFS symptoms.
Since MF/CFS is currently diagnosed based on having symptoms consistent with the condition for at least six months, it is important to keep track of your symptoms. A symptom diary can help your doctor make a diagnosis and rule out other conditions.
Researchers have identified abnormalities in the nervous, endocrine, and immune systems associated with ME/CFS. Several other conditions share similar physiologic abnormalities and may overlap or be comorbid with ME/CFS.
Fibromyalgia is a chronic condition characterized by chronic widespread muscle pain with tender points. It may also cause sleep disturbances, joint stiffness, mood disorders, cognitive impairment, and digestive symptoms. Like ME/CFS, the causes of fibromyalgia are not understood, and the condition can be difficult to diagnose.4
Myofascial pain syndrome is also characterized by trigger points, but the pain is more localized. The condition affects muscles and the connective tissue that surrounds them. The trigger points that cause pain in myofascial pain syndrome originate in the fascia, a thin layer of connective tissue that wraps muscle.
Myofascial pain syndrome is most commonly diagnosed in middle-aged women and affects the head and neck muscles. Unlike fibromyalgia, the pain does not occur throughout the body, but like fibromyalgia, the underlying cause is not fully understood, making it difficult to diagnose and treat.
Irritable bowel syndrome is a functional gastrointestinal disorder. It causes abdominal pain, cramping, bloating, constipation, and diarrhea. Like these other conditions, the underlying physiology of irritable bowel syndrome is not well understood. It is a chronic condition for which there is no highly effective treatment.
ME/CFS and its comorbid conditions are poorly understood, have no accepted diagnostic test, and are not easily treated. According to the American Myalgic Encephalomyelitis and Chronic Fatigue Syndrome Society, these are the best treatment/management options:
If you have ME/CFS and try some of these treatment/management options, go slow and try them one at a time. Keep a record of how you feel and any changes in your symptoms.
While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.