Myalgic Encephalomyelitis Community
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Post Exertional Malaise

Describing the relapsing of disease symptoms following physical or mental activity a “crash” or “hitting the wall”. The biomedical field describes this characteristic and hallmark feature of ME/CFS as post-exertional malaise (PEM) – a term that grossly understates the debility that comes with this disease-defining symptom.

Post exertional amplification of symptoms in ME/CFS patients, a hallmark symptom of damage to the aerobic energy system means that it is utterly counter productive to try to use aerobic exercise, such as graded exercise therapy, to improve health as directed by NICE guidelines.

Betsy Keller at Ithaca College research titled, “Inability of myalgic encephalomyelitis/chronic fatigue syndrome patients to reproduce VO2peak indicates functional impairment.” Keller used a 2-day cardiopulmonary exercise test (CPET) to show that physiological values in ME/CFS patients worsened on the second CPET, a phenomena unique to ME/CFS patients.

The Dutch Vermeulen team’s article titled, “Decreased oxygen extraction during cardiopulmonary exercise test in patients with chronic fatigue syndrome” They used CPET to show that oxygen extraction – or the ability of oxygen to be removed from the blood and used by tissues to support metabolism – was significantly lower in ME/CFS patients and could be a causal explanation for exercise intolerance in ME/CFS patients.

Mark VanNess at the Bristol Watershed after a screening of "Voices from the shadows"

Dr Nigel Speight at Bristol Watershed

7 Replies

Hi Ian,

Thanks for bringing up this subject.

I always use the term from the International Consensus Criteria now when i have to explain it to anyone. That is: 'Post Exertional Neuroimmune Exhaustion' IE not just exhaustion par se but exhaustion of the entire immune system and Central nervous system, so bringing the universally severe symptoms that PEM/PENE brings.

I always found the term post Exertional malaise difficult as it's better than fatigue but it's so so so much more than malaise and does not explain the vastly reduced abilities/increased disabilities during post Exertional set-backs that write us off completely during those periods, and with all our symptoms much worse.

Hope u haven't been too bad today Ian.

Sorry I'm running behind as usual with replies to messages and posts. I will catch up eventually! :-)

Take care,

Starbys :-) x


I would prefer both the PEA (post exertional amplification) along with PENE (post exertional neuroimmunal exhaustion) as I believe malaise grossly understates the debility.

That much agreed PEM is the term used by the Canadian Consensus Criteria which if we are ever able to achieve a definition of the disease with a thousand names, removing the most commonly used research criteria FUKUDA that makes no mention of post exertion then promoting the most commonly used criteria that does - the CCC is the best option in the short term. The reasoning why CCC is recommended as the best criteria for the NIH at the P2P along with the recommendation of retiring the Oxford criteria.

Jaon et al research


Nice job sharing info!

An important name change has been a topic of discussion for so many years now. Certainly, a part of the delay has been in coming to a better understanding of disease etiology and wanting to get it right.

Yet, another part of that delay, as we all know, has been just how long it has taken for governments to realize the importance of admitting to the existence of ME and the potential impact, even monetarily, upon governmental disability support and health care systems.

I personally wrote letters about this to Anthony Fauci, M.D. in the U.S.

He laughed it off as "alarmist" and fictional. That was in the early 90's.

And then, somehow, monies the U.S. Congress had allotted to CFS research was somehow diverted to purchasing equipment for other "pet research projects." CFS research was not taken seriously by these officers entrusted to properly utilize money as dictated by Congress. This was investigated by the GAO (General Accounting Office).

They were ordered to replace the money, over time, which further delayed research.

The U.K. has done a much better job of pursuing the "truths" behind the illness(es).

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The UK has the same problems Professor Simon Wessely hi-jacked M.E for the psychiatric lobby because neurologists did not want it. Wessely school had UK government and insurance giant UNUM backing the government cutting welfare while UNUM would only pay bio-med all in the mind no pay out.

Until 21 December 2011 the MRC had spent absolutely zero on bio-med research, anything in the previous fifty years had been charity funded so where £1.6 million does not go far when split among five projects a small celebration was in order.

Following the NIH P2P with hope that there will be some change report published 10th February 2015

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Interesting. Frustrating, too.


As a community we have moved further forward in the last five years than in the previous thirty, the group holding the money and influence will lose eventually because they have everything except the truth.

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Very encouraging!

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