Hi BoneBroth,
As you already know, I, too, in POIS acute phase, have marked hypotension. It has been the first objective way I had found to monitor the beginning and end of my POIS acute phase, by using a blood pressure monitor. In my case, low blood pressure duration and duration of all POIS symptoms are identical. I see hypotension as one of many effect of POIS in my case.
One of the best first thing I used to raise my blood pressure enough so that I am functional for work and daily activity is green tea. It is still part of my pre-pack !
I read your list, and about nicotine, I do not use it, but if anybody want to use it, I strongly suggest you use nicotine gums or lozenges, like those for tobacco cessation aids, instead of cigarettes. Smoking has no additional benefit over these other sources of nicotine, and has a tons of negative effects on the respiratory systems that nicotine gums and lozenges don't have.
Also, I have a normal, healthy renal function, so I often used salted water in order to raise my blood pressure ( not a good idea if you have renal insufficiency ! ). Very effective, and quite cheap. I used 2,5 ml ( 1/2 teaspoon) in half a glass of water. I repeat after 30 to 60 mins if needed. I combine this with ongoing water intake ( salt alone is not enough, it helps retain the water and raise your liquid volume, but if you are dehydrated, it does not help as much).
By normalizing blood pressure, the extreme fatigue is less, no more fainting sensation, it lowers the exercise intolerance as well. By exercise intolerance, we do not even talk about push ups here - I mean only standing up can become a problem with hypotension, and having to work in a standing position for long periods of time becomes an overwhelming challenge ! Stamina returns to an acceptable level too, although not normal, because my POIS has more bad effects than just low blood pressure.
( but with my overall pre-pack, things become very manageable see
https://poiscenter.com/forums/index.php?topic=2090.msg16604#msg16604 )