What could it mean biologically that both physical and cognitive exertion can cause PEM?

Yep. For it to work as a model, your brain would have to be able to clear most of whatever it was during a single night.

That's why I find it easier to conceptualise as a signalling problem, perhaps akin to what happens when you get one of those 24/48-hour viruses. It passes and you wake up feeling back to normal. You know it's gone as soon your brain's fully awake.

That's happened to me twice in ME/CFS. The first one was so abrupt I found myself struggling to control my legs when I first got of bed—I hadn't had muscles that responded that eagerly for years.

 

I self monitor playing video games a lot, in order to identify when its necessary to rest. I tend to become erratic, lose focus, lose ability to set and achieve goals. In effect, in the games I play, its less about getting things done than running around and not doing anything. I also lose the capacity to respond to challenges. I can still talk though, but my cognitive focus is different.

If I do not rest it just gets worse. If I rest I can come back to my game in a few hours, or sometimes as little as twenty minutes. I also find it better to switch between different games with different cognitive demands. I am also finding something similar with using the 30s rule to do resistance training or regular chores. I rotate body areas and types of exercise.

I did not do this kind of self reflection when I was working, all those years ago. However as a student I would structure my time for half an hour or an hour studying, and the same for resting or a different activity. I got more done that way.

 

Maybe relevant new study:

S4ME thread: Amyloid-forming potential of Betacoronavirus including SARS-CoV-2, 2025, Haddad et al (Heliyon)

Would either require prions stick around after acute infection, or the infection persists. Also apparently only some variants.

 

I’m amazed at how many studies you find, remember and understand, @forestglip

I don’t have the head to search for things now, but I wonder if eg the MS-field has found anything related to EBV if the nervous system can be attacked by prions? I know MS is caused by autoimmunity, but maybe there are more processes involved?

 

Ha no someone literally just posted it on Bluesky and it reminded me of the prion discussion here.

 

Today, I'm suffering from what I've been calling post-high crash. I found nicotine patch still lying around on my desk and wanted to find out if it's still effective after months of 100F heat during the summer while I was away. I slapped on the whole patch (7mg), went way too high and crashed this morning. I spent 4 hours in bed already after spending 0-2 hours/day for weeks. 7mg was apparently too much -- I don't remember having the same problem with 3.5mg. This post-high crash sometimes happens spontaneously. I get high for no reason and pay the price the next day with familiar depletion and ache that goes with PEM.

I would certainly think so. A theory should be able to explain different triggers of PEM with the same underlying mechanism, the same way it should explain different triggers of ME/CFS with a single mechanism.

For what it's worth, I think different exertions produce the same thing which in turn triggers PEM. Whether it's physical, mental or emotional, they all produce inflammation. And that low grade inflammation could be triggering PEM sickness in people hypersensitive to it. People talk about unfamiliar activities triggering PEM even if it is not as intense. So, even a localized peripheral inflammation could be triggering PEM.

 

Yeah, that might have been me. I use the term "intensity" to denote speed/weight, and "duration" for distance/time. It seems to me that the "damage" goes up exponentially as the intensity increases linearly. So, increasing your walking speed by 5% is equivalent to walking twice as far. I got the idea from watching Olympic skaters whose lap time drops about 5% whenever the distance is doubled. I tried different walking speed and that was pretty much what I got: I had to cut the distance by half whenever I increase my walking speed by about 5%. The problem, of course, was that I couldn't manage my daily activities precisely. So only way for me to be safe was to limit my walk speed to 90 steps/min.

[edit: grammatical]

 

As previously discussed, in many patients, the symptoms are not the same, depending on the triggering activity.

Four out of five people report differences:
https://www.s4me.info/threads/poll-physical-vs-cognitive-pem-same-or-different.16948/

Cognitive activity does not cause any additional fatigubility in my muscles for example, but it does exacerbate headache, brainfog etc for days.

In some patients it affects sleep which can mediate an increase in other symptoms.

Assuming that all triggers leads to the same symptoms is a fundamentally flawed assumption that has greatly held back research and led to substantial stigma against ME/CFS patients.

That is largely my experience too. Any muscular symptoms associated with cognitive exertion are actually due to how I held my body during that exertion, use of my eyes leading to eye pain etc.

 

I find the same with emotional exertion. Whether the emotions are positive, negative or mixed, there's a big change in how I hold myself. It uses a lot more capacity than, say, the bland neutral of sitting back listening to a factual podcast.

Laughing's probably worst of all. I laugh easily and a lot, and it's bloody knackering.

 

Maybe the different responses to different types of exertion is something we should try to highlight in a future fact sheet? Idk if there are any studies on it, but it should certainly be included in the next PEM-studies, and probably all exercise studies.

I also believe that there might be differences between year 1 and eg year 5, depending on what caused your ME/CFS in the first place.

 

And what about PEM from taking a bath? It doesn’t require more movement, but the stimuli seems to really mess with every single system.

 

Problems with hot baths might be due to an exacerbation of orthostatic intolerance.

 

When I was at my worst showers were difficult because of having to stand long enough and, as Trish points out, all the associated activity, however hot baths were impossible presumably related to the autonomic disruption. A bath would trigger an immediate worsening of symptoms whereas a shower if the right temperature would just add to the activity levels likely to trigger PEM.

Interestingly now I am a little better with orthostatic intolerance being less restrictive and better able to regulate my body temperature, I chose to have a bath rather than a shower because it involves less physical exertion.

 

This is partly where my current thinking is, but the decreased oxygen demand is due to both poor vasodilation and poor mitochondrial function.

ETA should be both demand and supply. The mitochondria has less demand, the blood vessels supply less. It might be these two are connected, one might be an adaptation to the other.

 

I don't have OI, but I work mostly from bed to keep my heart rate low. I get PEM from cognitive exertion surprisingly quickly, but only if I'm working on something unfamiliar where I have to think quite hard. Routine tasks are not a problem.

I also monitor my heart rate and I get PEM even if it stays around my resting heart rate.

 

Then why is it near universal in severe people that are completely horizontal that cognitive exertion causes PEM.