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What is Chronic Fatigue?

Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) International Awareness Day is May 12 [1]. “Chronic” means lasting over time and fatigue means, well, we all know it means being tired. SAFTE-FAST is used to monitor fatigue due to sleep loss or circadian misalignment over long periods of time. However, chronic exposure to fatiguing conditions is not the same thing as CFS.

ME/CFS is a neurological disease thought to be triggered by a viral-like illness. Long COVID shares many of the same features of ME/CFS and may develop using a similar biological pathway—a pathological, long-term reaction to an acute infection [2]. ME/CFS affects nearly 0.9% of the population worldwide [3]. The disease was first called “Myalgic Encephalomyelitis” following an outbreak at London’s Royal Free Hospital in 1955 [4]. Dr. Melvin Ramsay, MD, described the symptoms of a strange illness that affected more than 200 hospital staff members; the name comes from the disease’s symptoms: muscle pain (myalgia), effects on the brain (encephalo), spinal cord (myel), inflammation (itis)—Myalgic Encephalomyelitis, or ME for short.

In 1987, the Centers for Disease Control (CDC) voted to change the name after a series of similar outbreaks in the United States. The disease was renamed Chronic Fatigue Syndrome (CFS) in 1988. One of the reasons for the rename was that there has been no definitive evidence that pathogens prompt the development of the disease [5]. The name CFS focuses on the observable symptoms (debilitating fatigue, difficulty concentrating, short-term memory problems, sleep disturbances, and muscle pain) without insinuating the underlying cause. Patients and medical professionals prefer the more technical sounding (though potentially inaccurate) “ME”, feeling that “CFS” trivializes the systemic nature of this neurological disease. The compromise is to use both names, hence ME/CFS.

Fatigue is a vague and widespread symptom that arises from a number of different causes. Otherwise healthy individuals who work nights or regularly cross time zones for work experience fatigue because of lifestyle factors rather than an internal pathology. Patients with ME/CFS experience profound fatigue that is not relieved by rest. Their fatigue worsens after physical or mental activity, a symptom called post-exertional malaise (PEM). Other symptoms include unrefreshing sleep, dizziness, problems thinking and concentrating, worsened memory, and pain. Shift workers and transportation professionals are likely familiar with difficulties concentrating, poor sleep, faulty memory, and aching muscles as well. Even someone who works from home and has no reason to be tired may be nodding their head in agreement while reading that symptom list.

One of the most difficult issues with ME/CFS is getting the diagnosis in the first place [6]. Each patient may present different symptoms and there has been no consensus designed to provide a diagnosis. There are no tests for ME/CFS, so diagnosis is based on the symptoms alone. Patients can also experience long periods of recovery between relapses. Individuals with ME/CFS may frequently be misdiagnosed with a psychological illness such as depression or told that they are expressing social and emotional problems through physical symptoms. This kind of medical framing shifts the blame away from the provider, leaving patients feeling accountable for their own poor health [6].

A frustration that ME/CFS patients and SAFTE-FAST users share is coping with the stigma around fatigue. Somehow, we have internalized the idea that some causes of fatigue are acceptable while others are shameful. ME/CFS patients may feel validated if there were a blood test that could show that their exhaustion was due to a bad reaction to viral infection rather than something they “made up,” like emotions (which are very real, btw). Biomathematical modeling provides the same kind of objective confirmation that the problem is due to an external source—one’s overnight work schedule or jet lag rather than something that has been stigmatized as a moral failing, such as staying up late at night. This false dichotomy between acceptable and unacceptable reasons for being tired only serves to undermine fatigue risk management for operational populations as well as patients.

The goal of ME/CFS International Awareness Day is to increase awareness and education about the disease. This effort can benefit those who live with ME/CFS by connecting them to treatment resources and teaching communities at large how to accommodate the needs of ME/CFS patients. Education is a key point for fatigue risk management as well—not just learning about how work impacts cognitive ability but also providing workers with resources about medical diagnoses like ME/CFS that could contribute to feelings of exhaustion.



1. ME/CFS International Awareness Day.
2. Komaroff AL, Lipkin WI. ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature. Front Med (Lausanne). 2023; 10: 1187163. Available from:
3. Deumer US, Varesi A, Floris V, et al. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): An Overview. J Clin Med. 2021; 10 (20). Available from:
4. Hanson MR. The viral origin of myalgic encephalomyelitis/chronic fatigue syndrome. PLoS Pathog. 2023; 19 (8): e1011523. Available from:
5. Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group. Ann Intern Med. 1994; 121 (12): 953-959. Available from:
6. Bayliss K, Goodall M, Chisholm A, et al. Overcoming the barriers to the diagnosis and management of chronic fatigue syndrome/ME in primary care: a meta synthesis of qualitative studies. BMC Fam Pract. 2014; 15: 44. Available from:


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