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

Taking a shower at a lower temperature helps, a bit, for me. The blood has to cool down the hotter skin and is taken away from from other duties?
Oxygen seems to get lost between arteries and tissues, what blocks it ? (vasoconstriction in me, I think)

When muscles have to work harder they don't get more oxygen, resulting in damage. Running on empty. Repairs need more energy too?

I do get PEM from cognitive exertion. My tillt table test resulted in part of my brain going offline for two days.
It felt like a preview of dementia, really traumatic. I needed answers on how to prevent that from happening again.
My PEM lasted a month. During that time my "research" was not getting anywhere.
It took me about 4 months to finally conclude oxygen deprivation during the test must have been the cause and over 12 hours of traveltime didn't help either.
How to prevent it. No tilt table test ever again, I'm not going back for seconds. No other prevention required. That put my mind at ease again.

Something beautiful happened too. I seem to have a back-up system in my brain. I had severe brainfog during my appointment, but I have a video recording of that visit, without the fog, even 4 years later it's mostly there. I could even give better answers to the questions asked during the test. (on sound, vision etc)

 

Can you be more specific what you mean by PEM in this context (which symptoms)?

PEM is not always experienced the same.

 

Following an exertional trigger (with or without delay), worsening in functional capacity and symptoms with duration and intensity that is far higher than what would be reasonably expected for someone with a non-ME chronic illness.

If compounded, these worsenings can be permanent. They also sometimes produce new symptoms or symptoms that or only present during these worsenings, on top of exacerbating existing ones.

 

Which symptoms though?

I get different symptoms as a result of cognitive exertion (brain fog, headache, drowsiness) than I do from muscular exertion (sore throat, persistent fatigubility, muscle cramps etc), and the onset time frame is different too.

 

To me I get the exact same worsening in symptoms whether the exertion was cognitive or physical in nature. I get myalgia, cramps, sore throat etc from cognitive exertion.

 

I can think there is ample evidence that people report "cognitive PEM" from "cognitive exertion". But to me it isn't quite clear whether there are differences in onset timeframe, whether there are differences in symptoms experienced after "cognitive exertion" vs "muscular exertion" and at what percentages all these differences occur. I think another important question would be: What is the interaction between the general cognitive difficulties reported in ME/CFS and these phenomena?

As extremely unfortunate as it is that nobody has looked into this, I think we should be careful to not overinterpret some of the data from this site.

Since things don't always appear to be super homogenous in ME/CFS I wouldn't be surprised if things aren't very homogenous here either.

 

https://en.m.wikipedia.org/wiki/Proteinopathy
protein misfolding disease