"Cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia... van Campen et al, 2020

Reassuring to see rigour like this:

 

Although they were able to find a relationship between orthostatic intolerance symptoms and a reduction in cerebral blood flow, there was still a lot of variation:

 

No talk of deconditioning/similar in the paper that I recall

 

This is just spelling out the corollary of the findings:

 

The abstract doesn't mention the hypocapnia (reduction in carbon dioxide) that was found:

 

https://twitter.com/user/status/1228814824584437760

 

The study mentions this elephant in the room (hypocapnia when upright but not when supine) but does not discuss it or its implications as far as I can see.

 

There's prior research suggesting it can't be blamed solely on hypocapnia. CBF disruption occurs first, the hypocapnia follows and reinforces it. You also don't get the same symptoms from voluntary hyperventilation.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4016155/

 

I'm aware, I wasn't suggesting hyperventilation. Still, it's a significant finding which should be investigated IMO. Why is it happening only upright?

 

Commonly held view is that orthostasis results in central hypovolemia, particularly if there's neuropathic factors contributing to that. Knock-on effects lead to respiratory activation.

Various other reasons for hypocapnia are possible, hyperventilation features in mito disease and other myopathies for example. But I guess the focus is on mechanical changes due to it being reliably triggered on standing.

 

https://twitter.com/user/status/1228822361945886722

 

I think this study is really important. I often wondered why researchers weren’t looking into this. I don’t know of any other conditions (except perhaps PoTS alone - and even then, not to the extent of ME and PoTS together), where patients have to continuously be lying flat and feel absolutely dreadful when upright even just a few seconds or a minute upright for those with severe ME. It stops you from doing anything at all. I’ve never heard of it even for example in the most severest lupus or severest autoimmune conditions on the forums I went on a few years ago. Someone I knew who was very very sick, terminally ill, only had to lie flat in the last few weeks of her life.

But why could this be happening to us for ME? @Ryan31337 when you say being upright causes central hypovolemia, does that mean the brain is not getting enough of a volume of blood? And why could this happen - what do you mean by mechanical changes?

and I also wonder - are there not medicines to help bring more blood back to the brain?

 

This may or may not be relevant, but my low CO2 was attributed to hyperventilation by at least two prominent ME/CFS researchers. Both offered me the services of a breathing coach. I declined.

 

That's disturbing. I know someone who got told orthostatic symptoms were due to 'fear of standing'.

 

Gee....why am I afraid of standing? Maybe because when I do so I faint? NAH! Couldn't be.


Misdiagnosis of anxiety instead of OI is far too common!
I hope this study helps end this mistreatment!

 

Unfortunately this applies to women's heart disease as well.

 

That's terrible. I hope it wasn't one of the good guys.