ME (and Long Covid) are NOT just fatigue and are Not defined by fatigue.
Fatigue is a Symptom, not a disease. Fatigue is a Symptom of a great many medical conditions and a factor of daily life for many.
But ME Is Not Fatigue, or Chronic Fatigue
- And please everyone, stop using 'Chronic Fatigue' as a name for ME (or LC) because it confuses, and trivializes what is a disabling, sometimes fatal, WHO/CDC/NIH classified Neurological/Immune Multisystem disabling, sometimes fatal, disease.
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'Diagnosis and Management of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome'
Mayo Clinic Proceedings.
' Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic neurologic disease often preceded by infection.
It is common and debilitating, with a prepandemic population-based prevalence of 1 to 2.5 million in the United States alone and a lower quality of life on average than multiple sclerosis, chronic kidney failure, or congestive heart failure.
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There has been increased interest in ME/CFS recently because of its significant overlap with the post-COVID syndrome (long COVID or post-acute sequelae of COVID), with several studies estimating that half of patients with post-COVID syndrome fulfill ME/CFS criteria.4
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Whereas the exact cause of ME/CFS is unknown, dysfunction in the neurologic, immunologic, endocrinologic, cardiovascular, and metabolic systems has been found in people with ME/CFS and post-COVID syndrome.
Research is underway to identify diagnostic markers and therapeutic targets.
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The pathognomonic symptom of ME/CFS is post-exertional malaise (PEM) or post-exertional symptom exacerbation. Post-exertional malaise is a flare in symptoms or the appearance of new symptoms after exertion, often manifesting after a characteristic 24-hour delay; however, 12 to 48 hours is common. Physical activity, cognitive overexertion, and sensory overload may all trigger PEM. It may take a person with ME/CFS days, weeks, or even months to return to previous baseline after PEM.
[NB - PEM can escalate and become lifelong, with No return to previous baseline of functioning, the people remaining very severely sick with no improvement]
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It has been reported that patients with ME/CFS have impaired oxygen extraction on cardiopulmonary exercise testing in proportion to the severity of their symptoms, with both oxygen extraction and workload being decreased on the second day of 2-day cardiopulmonary exercise testing.
https://www.mayoclinicproceedings.org/article/s0025-6196(23)00402-0/fulltext
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