@ahimsa I really wanted to reply to this thread sooner but couldn't find it! Thank you for everything you typed out. Just to clarify, do you mean that the tachycardia in your sleep was related to autonomic dysfunction and NMH? I am not sure in my case if the tachy in my sleep was related to pushing too hard during the day. All I know is that it was the very first symptom that I had that something was really wrong and it started in Jan 2013 (10 mos after I had mono and two weeks following an unknown infection.) Did yours occur exclusively during REM sleep while you were actively dreaming? Did you find a correlation between resting and not having the tachycardia in your sleep? I drink all the Pedialyte, Vitalyte stuff, too. I also feel better when I do not eat dinner but then I started having hypoglycemia episodes and now I force myself to eat more whether I want to or not. What kind of co-infections do you mean? Also, do you mean that the tachy in your sleep is totally gone on it's own? Mine is 99% gone with a beta blocker but every once in a while, I will still have an episode (but very rarely.) The initial cardiologist that I saw was a joke and I don't think she believed me that I was having tachy in my sleep up to 160 and 170 bpm. She said, "Well, I can get my HR that high in my spin class..." and I said, "But I am not in a spin class, I am SLEEPING!" Needless to say I switch to a new cardio who did a Zio Patch test which captured the episodes. She believed me and said they were IST and gave me the beta blocker. Neither mentioned dysautonomia or OI and I did not know the terms at the time to even ask. I am now seeing a third cardio (my current doctor) who knows about dysautonomia but does not know anything about ME/CFS. I did a full sleep study in 2013 which showed no sleep apnea and normal blood oxygen levels. I had very mild CFS at that time and was still working full-time and had no idea what my diagnosis was, only that I had weird tachy in my sleep. I took the beta blocker for the sleep study (which I regret) so the episode did not occur and I barely slept the entire night and it was a waste of time. I did not realize that at the time and am still not sure if I understand the full connection because when I am laying flat and resting or sleeping, it is the only time I can breathe normally (except for those episodes.) When you say co-infections, what do you mean? I have EBV and VZV but are you referring to viral stuff or bacterial or something else? For me, it has been worth it to travel to see an ME/CFS specialist but I know this is a personal choice and it definitely involves time, money, energy, etc, and the travel is very difficult for me in my current state (and I only do it twice per year.) It is a leap of faith that at present I feel is worth it (for me.) This is similar for me except that my BP is always low and not just when I am standing. Also, I have no problems sitting at a desk (or sitting anywhere) but I have major problems with standing, walking, eating, etc. Do you mean that you actually faint? I have never fainted in my life no matter how low my BP has gotten. This is pretty similar to me except I don't have much dizziness or brain fog and my worst symptoms are shortness of breath and chest pressure which at it's worst is chest pain that my cardio thinks are microvascular angina spasms. I do everything you said here except for Florinef which made me sicker. Have you ever had a Zio Patch test? I really think you could capture it on that. Actually it was very helpful and you were very helpful in the past when we were discussing Midodrine. I really appreciate it. I relate to a lot of your experiences and the difficulty in just walking across the room. I have never had night sweats though. Not rambling and very helpful! Glad I am not the only one who types long posts!