- Last Updated: 15 March 2021 15 March 2021
The article below is germane to ME/CFS patients who have post-exertional malaise. This is a requirement for meeting the 2003 Canadian Definition of ME/CFS and the proposed definition in the Institute of Medicine Report Guide for Clinicians in 2015. The majority of ME/CFS patients meeting the 1988 CDC criteria have this symptom. Far fewer of those meeting the 1994 CDC or other definitions will have this symptom. A patient who lacks post-exertional malaise as described below does not have mitochondrial dysfunction. This type of exhaustion is unique to mitochondrial problems.
This article is intended to be read by lay readers as well as health care providers. Thus, we will sometimes explain medical terms. We will use the term ME/CFS for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome/Chronic Fatigue and Immune Dysfunction Syndrome in deference to our health-care provider readers.
Mitochondrial dysfunction is only a partial cause of the fatigue most ME/CFS patients have. It has been well documented that there is an abnormal increase in cytokines (chemicals released by the immune system) in ME/CFS patients following mild exercise. This causes another type of fatigue on top of the mitochondrial dysfunction fatigue discussed below. Cytokines in general, without the exercise trigger, can cause fatigue. There are probably additional causes of fatigue (such as orthostatic intolerance) as well.
The author of this article is an elected member of the New York Academy of Sciences, and Sigma Xi: The Scientific Research Honor Society, as well as other scientific societies. She is also a past member of the board of the Massachusetts CFIDS/ME & FM Association.
Notice about names
The Massachusetts ME/CFS & FM Association would like to clarify the use of the various acronyms for Chronic Fatigue Syndrome (CFS), Chronic Fatigue & Immune Dysfunction Syndrome (CFIDS) and Myalgic Encephalomyelitis (ME) on this site. When we generate our own articles on the illness, we will refer to it as ME/CFS, the term now generally used in the United States. When we are reporting on someone else’s report, we will use the term they use. The National Institutes of Health (NIH) and other federal agencies, including the CDC, are currently using ME/CFS.
Massachusetts ME/CFS & FM Association changed its name in July, 2018, to reflect this consensus.