What do we actually know about orthostatic intolerance?

We've had a very population thread about needing to lie flat, started by @Jonathan Edwards, and @Mij has just started a very interesting thread about some new research showing the uselessness of salt for OI.

From reading about OI on the forum, I'm wondering if anything is actually solidly known about OI. Weird if it's not, for a symptom that can be so very disabling - you can't do much if you can't be upright.

Do we think anything is known?

If this is an ignored or incompetently researched area, can we change the situation?

 

I think it's best not to think of OI as a symptom. It is an umbrella term for a set of symptoms and conditions (e.g., POTS) that appear or worsen with upright posture. I think we know that this is due to problems with the autonomic nervous system—that is, OI is a form of dysautonomia. There seems to be many different ways that a patient can end up with OI.

There's some good research in this area, but it's definitely neglected if you consider the prevalence of OI and its impact on QoL.

I don't think this is known for sure, but the usual answer for why symptoms are worse in the morning or first half of the day is that we are dehydrated and have just spent ~9 hours still without the action of muscles to pump blood around. This is the answer Dr Gupta gives. I suspect there are others factors involved.

 

The interesting thing for me is that I feel dehydrated during delayed PEM when my OI is at its worst- but I'm not dehydrated. I keep very well hydrated at all times with electrolyte drinks.

Who is Dr. Gupta?

 

I just had the exact same thing. I've been unwell with what might be some virus and had three days of constant dry-mouthed thirst, no matter how much I drank, accompanied by much worse OI. (Not diabetes - had a fingerprick blood test just in case I'd suddenly acquired it). I was wondering what the mechanism was.

 

I am not sure that works. When lying flat both tissue fluid and venous blood will find it easiest to return to the central venous blood. If you have a couple of cups of tea for breakfast you are unlikely to be significantly dehydrate (kidneys tend to shut down urine production at night). Muscle pumping gets blood back to the central veins within minutes at most so once dressed that shouldn't be a problem.

It is likely that the autonomic system is involved but other mediators may be involved. The mediators of fever have a typical diurnal cycle with two peaks and two troughs. Cortisol has a trough in the morning and so on. SO it might not be dysautonomia, more dys-someotheromia showing up through autonomic signals?

 

This is interesting. I wonder if anyone is looking into it. Do you have a general sense of the field and whether it's making progress?

 

Hm.
My sense is that it needs a tidy out.

 

I wish we knew more — this is an area worthy of further research. I agree that dysuatonomia is only part of the picture. My life would be much better if I felt throughout the day how I do in the evenings. It's interesting that both ME and POTS/OI follow this pattern in most patients.

 

Yes, very interesting. I was not aware of that. Maybe more evidence for signalling involving brainstem or hypothalamus.

 

The brainstem has been implicated many times in OI and ME/CFS and fibro and Gulfwar syndromes. I've had it suggested to me, for me, in two of those four, once after a 4-day stay at a well-regarded study for ME/CFS. The question for me is, what damages the brainstem and then maintains that damage, or better/worsens it.

That damage just doesn't appear, uncaused, and then subside, only to resume and persist without ongoing stimulus.

 

Because of @Jonathan Edwards 's interest in this, I had thought about maybe trying to set up a high-profile poll thread to catch the eyes of lots of people here on the forum, and to ask them to note through the day, hour by hour, whether they have had to lie down. The poll options would list each hour in the day and we could check all that applied, allowing us to get that granularity of data, if it would be useful.

I can find it hard to remember exactly what my patterns are, and they can change if I get extra-ill, so I think this is the only way I'd be able to answer the question.

Maybe it's just me, but I've adapted unconsciously to so much sh*t that I'm no longer aware that I'm doing it.

 

I am so much better cognitively in the evening, though it took me a long time to figure that out because I was still trying to do orthostatically challenging things like shower early in the day and thus scuppering myself indefinitely. A frequent one for me is that I cannot talk all day but can talk in the evening (though not after an evening shower).

But physically I usually dwindle as the steps rack up during the day.

So maybe a poll could ask about cognitive and physical symptoms separately?

 

I can sit up all evening watching a show, even after going out for a brisk one hour walk. My voice is smoother and not as chopping and harsh as it is during the day. Cognitive function much better too.

A poll would be helpful. I've read evenings are better for some posted sporadically on the forum.

 

I am always better in the morning and I worsen as the day drags on. It's not due to sleep because my sleep always sucks. I've assumed, in part at least, that it relates to OI and POTS.

I seem to recall a poll about morning vs evening and I thought it was here. Maybe not. But I do recall most struggled in the morning and fared better as the day unfolded, and so people like me were in the minority..

 

Symptoms and Causes
What are the symptoms?
Orthostatic hypotension happens more frequently — and with more severe symptoms — in the morning. That’s because blood pressure is normally at its lowest when you wake up in the morning.
LINK

 

My blood pressure is a little high on the first take, a little less on the second, and normal in the morning. I didn't realize this until my GP started taking 3 test readings in a row.

My heart races in the mornings but not in the evenings.

I would like to know my BP reading the first and second day during delayed PEM.

I don't know what it all means.

 

The link I posted says 'lowest' during the morning. Does that mean it's low or does that even matter?