PEM-like descriptions and accounts in non-ME illnesses

[Kitty]

Anyone aware of any hard evidence either way?

I wonder if that'll exist, given that it's not very well characterised in ME/CFS.

Unless it was tackled in one of the DecodeME questionnaires (I completed them but can't remember much now), we may need a research project to work out how to describe it, then to get data on what proportion of people experience which symptoms, when, and for how long.

 

[Denise]

For something unrelated I was doing today I searched for a definition of PEM/PESE. This came up (I hadn't seen this portion of the site Library Of Medicine before)

Postexertional symptom exacerbation

MedGen UID: 752115
•Concept ID: C2732413
•Sign or Symptom
Synonyms:

Excessive postexertional fatigue; Exercise-induced malaise; Post Exertional Malaise; Post-Exertional Malaise; Postexertional fatigue; Postexertional malaise

SNOMED CT:

Postexertional fatigue (444042007); Excessive postexertional fatigue (444042007)

HPO:

HP:0030973


Conditions with this feature
Autosomal dominant childhood-onset proximal spinal muscular atrophy with contractures

Myofibrillar myopathy 10

https://www.ncbi.nlm.nih.gov/medgen/752115

 

[PrairieLights]

Channelopathies have PEM-like delays of symptom exacerbation, typically 12 to 24 hours after exertion. What I find particularly interesting is their version of PEM comes after resting following exertion. Mornings are frequently bad for such people precisely because rest is involved.

I get PEM in what I call a few different arcs.

This sounds similar to one I get on good days.

On these days I can go out in my normal pacing level and might do a bit more. As long as I don't sit or lay down I feel ok. Soon as I sit down I feel aches and stiffness creeping into my muscles, I start yawning and feel tired or fuzzy headed. My body feels like it's yelling at me to not let people talk to me and it's time to lay down.

This passes after about an hour or so laying down (sleep not needed). I may or may not get a more delayed PEM fatigue the next day as well.

 

[Yann04]

I get PEM in what I call a few different arcs.

This sounds similar to one I get on good days.

On these days I can go out in my normal pacing level and might do a bit more. As long as I don't sit or lay down I feel ok. Soon as I sit down I feel aches and stiffness creeping into my muscles, I start yawning and feel tired or fuzzy headed. My body feels like it's yelling at me to not let people talk to me and it's time to lay down.

This passes after about an hour or so laying down (sleep not needed). I may or may not get a more delayed PEM fatigue the next day as well.

I have that too. Like a sort of if I keep on pushing it I can kind of ignore my symptoms, my body seems to pump adrenaline and I do okay. But it’s once I stop that activity and the adrenaline wears down I start feeling awful.

 

[JemPD]

I have that too. Like a sort of if I keep on pushing it I can kind of ignore my symptoms, my body seems to pump adrenaline and I do okay. But it’s once I stop that activity and the adrenaline wears down I start feeling awful.

yes.

I must say i am grateful for your posts Yann, I often think 'yes thats exactly like me' & it helps so much, especially with the stranger phenomena like this.

 

[Yann04]

I must say i am grateful for your posts Yann, I often think 'yes thats exactly like me' & it helps so much, especially with the stranger phenomena like this.

Same. It feels good to have someone who understands. Especially the PEM from sensory inputs part.

 

[forestglip]

Mitochondrial complex V dysfunction possibly can cause PEM:

Case report: mtDNA deletion m.8753_16566 with < 10 % heteroplasmy in muscle and isolated complex-V dysfunction misinterpreted as chronic fatigue syndrome over 21-years (2025, Clinics)

An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients (2020, Int. J. Mol. Sci.)

 

[DigitalDrifter]

@Yann04

The sensory symptoms of Autistic Burnout can present similarly to ME.

 

[Colleen Steckel]

I have been looking into this topic for a while. The more I look, the more I find post-exertional malaise discussed in other conditions (and in healthy controls). I started a list here.

I see there are more references in this thread so it needs to be updated.

Note the Beyond ME/CFS IOM report discusses healthy controls having PEM. "The prevalence of PEM in healthy control subjects is considerably lower than in ME/CFS patients, ranging from 4 to 8 percent". Page 80 - https://www.ncbi.nlm.nih.gov/books/NBK274235/pdf/Bookshelf_NBK274235.pdf

The confusion about this symptom is another reason I prefer the International Consensus Criteria - post-exertional neuroimmune exhaustion that has a much more comprehensive description. I wrote about that here: https://colleensteckelmeiccinfo.substack.com/p/pem-is-not-equal-to-pene

 

[Jonathan Edwards]

I have been looking into this topic for a while. The more I look, the more I find post-exertional malaise discussed in other conditions (and in healthy controls). I started a list here.

I wouldn't take too many of those accounts seriously, especially when including imaginary diseases like Shoenfeld's ASIA. Gulf War Syndrome patients simply seem to have found exercise more painful and exhausting. Data based on questionnaires I think is probably a waste of time. When taking a history you do not just tick on a list, you evaluate symptoms in context, just as you do not identify a four legged creature as a red setter if it has horns even if otherwise it looks like a red setter!

The ICC are based on arbitrary speculations about involvement of various systems for which we have no theoretical or evidential basis. I threw them in the bin long ago. I would recommend anyone interested in a scientific approach does the same!

 

[Colleen Steckel]

For something unrelated I was doing today I searched for a definition of PEM/PESE. This came up (I hadn't seen this portion of the site Library Of Medicine before)

Postexertional symptom exacerbation

MedGen UID: 752115
•Concept ID: C2732413
•Sign or Symptom
Synonyms:

Excessive postexertional fatigue; Exercise-induced malaise; Post Exertional Malaise; Post-Exertional Malaise; Postexertional fatigue; Postexertional malaise

SNOMED CT:

Postexertional fatigue (444042007); Excessive postexertional fatigue (444042007)

HPO:

HP:0030973


Conditions with this feature
Autosomal dominant childhood-onset proximal spinal muscular atrophy with contractures

Myofibrillar myopathy 10

https://www.ncbi.nlm.nih.gov/medgen/752115

Were you able to find where it states that this condition has PEM? I'm not finding it other than in the list saying this condition has that symptom.
What's weird is that it doesn't include ME/CFS as a condition with this feature...

 

[Colleen Steckel]

I wouldn't take too many of those accounts seriously, especially when including imaginary diseases like Shoenfeld's ASIA. Gulf War Syndrome patients simply seem to have found exercise more painful and exhausting. Data based on questionnaires I think is probably a waste of time. When taking a history you do not just tick on a list, you evaluate symptoms in context, just as you do not identify a four legged creature as a red setter if it has horns even if otherwise it looks like a red setter!

The ICC are based on arbitrary speculations about involvement of various systems for which we have no theoretical or evidential basis. I threw them in the bin long ago. I would recommend anyone interested in a scientific approach does the same!

To clarify - you are saying all the researchers who are using the ICC to select patients are not using a scientific approach? If that is the case, I strongly disagree. We are seeing the importance of stratifying patients using the ICC.

See the list of researchers here:
See the stratification section in that list for evidence of the importance of stratificaiton.

Do you feel the same about the CCC?

I have had many conversations with people who have Gulf War Illness. Their experience of symptom exacerbation looks a lot like mine.

 

[Denise]

Were you able to find where it states that this condition has PEM? I'm not finding it other than in the list saying this condition has that symptom.
What's weird is that it doesn't include ME/CFS as a condition with this feature...

I did not find anything else and was quite surprised ME wasn't listed....

 

[Jonathan Edwards]

To clarify - you are saying all the researchers who are using the ICC to select patients are not using a scientific approach?

Pretty much, yes. ICC is based on a pre-formed hypothesis that has no empirical base so is unscientific. Simple as that. Most of the categories of symptoms assume pathology that we have never found.

See the list of researchers here:

I see a list of papers. It includes some of my own group, others I know well and still others I prefer to keep a distance from. My own group certainly didn't follow ICC. I am not sure what the significance of the list is.

Stratification has nothing to do with diagnostic criteria.

Do you feel the same about the CCC?

The CCC are less hypothesis driven, although they still suffer from the problem to a degree. I respect CCC because they were designed to define a group that had been diagnosed both as ME and CFS and to identify what merited the term ME/CFS. ICC seems to have been a retrograde attempt to resurrect 'ME', which just perpetuates the confusion with ME as defined by Acheson.

 

[mariovitali]

Fereshteh Jahaniani with PhD in pharmacology wishes to explore the connections between fluoroquinolones and mitochondrial damage : https://twitter.com/user/status/1914448741073084721

 

[poetinsf]

I have been looking into this topic for a while. The more I look, the more I find post-exertional malaise discussed in other conditions (and in healthy controls).

If IH or CCI can mimic ME/CFS, I suppose there are other conditions that can also mimic ME/CFS. The fatigue and PEM in those conditions wouldn't be classified as ME/CFS though, since they are explained by the underlying conditions. But we could call them comorbid-ME/CFS related to or caused by the main condition.

Something must be pinching the neuro-immunology in those conditions to make the patients hypersensitive to exertion. I still think studying those conditions to figure out what is causing the hypersensitivity, and how, may lead to a critical clue to the real ME/CFS.

 

[Snow Leopard]

Not specifically PEM (because they didn't bother mentioning it), but ME/CFS like-symptoms post-GBS show a similar sex ratio in GBS patients.

https://link.springer.com/article/10.1007/s00415-006-0163-6

Anecdotally, I see patients suffering from this reporting PEM like symptoms for a few days after they try to exercise.

Behan/Chaudhuri also wrote in 1999:

The post-GBS fatigue symptoms are very similar to post-viral fatigue symptoms or chronic fatigue syndrome (CFS)

https://pubmed.ncbi.nlm.nih.gov/11054483/

 

[forestglip]

ME/CFS like-symptoms post-GBS

For anyone else that wasn't sure: Guillain-Barré syndrome

 

[forestglip]

S4ME thread: Postorgasmic Illness Syndrome: Insights from Recent Literature on a Rare but Fascinating Disorder, 2025, Wdowiak et al

Post-orgasmic illness syndrome (POIS) is a rare condition characterised by flu-like and allergic symptoms that develop within hours of ejaculation and last for several days.

News article linked in above thread:

A rare and poorly understood condition known as post-orgasmic illness syndrome, or POIS, causes a wide range of flu-like and allergic symptoms following ejaculation. These symptoms, which can include exhaustion, difficulty concentrating, and muscle weakness, often begin within minutes to hours after orgasm and can persist for several days.

The most widely accepted standards [...] include flu-like symptoms such as fatigue, feverishness, and irritability; onset of symptoms shortly after ejaculation; recurrence in nearly every ejaculation; and a duration of symptoms typically lasting between two and seven days.

Later research has expanded upon these findings. In what remains the largest study of POIS to date, researcher Natale and colleagues in 2020 surveyed 302 men, 268 of whom met at least three of Waldinger’s diagnostic criteria. The most commonly reported symptoms were difficulty concentrating (reported by 84% of participants), extreme fatigue (83%), irritability (74%), and muscle weakness (70%)

Timeline and symptoms somewhat comparable to PEM.

 

[Lou B Lou]

I have been looking into this topic for a while. The more I look, the more I find post-exertional malaise discussed in other conditions (and in healthy controls). I started a list here.

I see there are more references in this thread so it needs to be updated.

Note the Beyond ME/CFS IOM report discusses healthy controls having PEM. "The prevalence of PEM in healthy control subjects is considerably lower than in ME/CFS patients, ranging from 4 to 8 percent". Page 80 - https://www.ncbi.nlm.nih.gov/books/NBK274235/pdf/Bookshelf_NBK274235.pdf

The confusion about this symptom is another reason I prefer the International Consensus Criteria - post-exertional neuroimmune exhaustion that has a much more comprehensive description. I wrote about that here: https://colleensteckelmeiccinfo.substack.com/p/pem-is-not-equal-to-pene

'Note the Beyond ME/CFS IOM report discusses healthy controls having PEM. "The prevalence of PEM in healthy control subjects is considerably lower than in ME/CFS patients, ranging from 4 to 8 percent". Page 80 - https://www.ncbi.nlm.nih.gov/books/NBK274235/pdf/Bookshelf_NBK274235.pdf '


Healthy controls, by definition, do not get PEM. What waffle.