Interesting Thread.
It sounds like there may be an "Acetylcholine subtype" of POIS. It could be identified by the fact that a hot shower makes the POIS symptoms more severe, and a cold shower brings relief ( see
https://en.wikipedia.org/wiki/Myasthenia_gravis#Ice_test , where it is explained that the acetylcholinesterase activity decreases at lower temperature ). Caffeine could also be detrimental to those POIS sufferers, but that would have to be confirmed, though.
This could allow some predictions, if some other members would confirm the same pattern. It would predict that if a POIS sufferer has his symptoms worsened by a hot shower, chances are he will have a good relied by using a cholinesterase inhibitor , like Mytelase, and from otther products that helps with acetylcholine levels, in particular in the muscles ( weakness) and brain ( lack of memory and focus). As cholinesterase inhibitors are usually are on prescription only, consult your physician. Huperzine A seems to be an exception, being a natural product having cholinesterase inhibition properties, and is available without prescription, but again, consult with a health professional before using it.
Some other natural products can raise acetylcholine level in another way, like lecithin, a precursor of acetylcholine, which is a pretty safe product, unless you are allergic to soy or eggs. And if I remember it well, Outsider said he has to take lecithin, along with Mytelase, in order to get relief.
Out of curiosity, I would like to ask to Vincent_M if his symptoms get worse after a hot shower. Then it would be consistent with what Outsider and FloppyB has described. If any other members has is symptoms worsen by a hot shower, it would be interesting to hear from them as well.
My symptoms are not worsened by a hot shower, so it is possible that taking Mytelase had little to no effects for my POIS. If I try Huperzine one day, I may see, but as it also is a NMDAR blocker, and they usually are good for me, my results wouldn't be conclusive. Mytelase is not available in Canada, so I won't be able to challenge my hypothesis on myself, and I surely not go for more potent drugs like donezepil, and wouldn't advice anybody to do so without medical supervision. I have never noticed if lecithin and soy had or not a particular effect on my POIS, but I have been taking soy beverage for years ( instead of cow milk), so I don't lack lecithin in my body.
Well, some POIS sufferers may now take the "Hot shower challenge", and after, for relief, the ice bucket challenge