Head-down bed rest impairs vagal baroreflex responses and provokes orthostatic hypotension
journals.physiology.org/doi/abs/10.115…

30 days head down tilt (HDT) caused 4 of 10 healthy participants to faint after standing up for 5 minutes. some interesting stuff going on...
Heart rate:
Those who did faint, had a much smaller increase in heart rate on standing, just 23 ± 5 bpm, compared to non-fainters 49 ± 10 bpm

This suggests high heart rate is protective of fainting (in these very peculiar conditions) graph showing heart rate of...
Blood pressure:
Diastolic blood pressure had a similar response for fainters & not fainters, but systolic blood pressure reduced by about 15 mmHg for fainters, with no such change for non-fainters

there was similar plasma volume reduction in both groups graph showing systolic bloo...
study also looked at baroreflex responses:
plasma volume (PV) fell before baroreflex response changed during HDT

PV then stayed low but stable; baroreflex slopes declined progressively

PV restored within 1 day of ending HDT, but baroreflex remained depressed for at least 5 days
"although our data do not rule out a contribution from reduced blood volume (BV), they point away from reductions of BV as the sole cause of the baroreflex abnormalities that developed during bed rest"
laying down and sitting norepinephrine and epinephrine were similar pre- and post-HDT

all this suggests to me that plasma/blood volume is less of a contributor to orthostatic intolerance/hypotension than other factors. whether these findings translate to #POTS = ❓❓❓

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More from @angryhacademic

Jun 14
I think so much in life there's a System and once there's a System us peoplebots follow that System and cannot deviate. Because theres a System no one takes accountability. The System speaks the only truth. The System is its own being. No one can overrule the System.
No one is accountable to the System and the System is accountable to no one. The System is the system and only the System can change the system. But since the System is not real, the system cannot change.
Once you see this, you will see it everywhere.

It shows why its so difficult to change the System, and why activists often get left chasing their tails to get answers and induce change.
Read 6 tweets
Jun 13
The #VDPS send me their decision today.

They accept causality to the vaccine on the following grounds:
My acute flu-like side effects
Tinnitus

Therefore they consider me 1-5 % disabled from the vaccine, and ineligible for payment

#vaccineinjuries #postvac
The document is very long and i need to re read to check ive interpreted correctly. Currently im quite in shock. The vaccine has ruined my life. Based on others, i expected rejection but how theyve determined < 5 % disabled is beyond me
Since the vaccine in March 2021, ive had about 6 months off work sick due to being near bedbound.

I was found to have multiple blood clots in my lungs, and since then, my risk of clotting is so high i am on anticoagulants indefinitely
Read 17 tweets
Jun 12
Cardiovascular Deconditioning (20 Hours Bedrest with -5° Head-Down Tilt (HDT)) in Middle-Aged Healthy Men
sci-hub.se/10.1016/0002-9…
authors suggest during HDT MAIN cause of deconditioning is "an altered distribution of body fluids & intravascular pressures" & shift of fluid to head
this is potentially VERY important for #POTS: it suggests that our dysregulated body water regulation can be a primary source of deconditioning-like cardiovascular issues.

this means: fix the haemostasis problems to improve cardiovascular condition

#MedTwitter
this study was in a very different context to POTS so we can't read too much into it. HDT shifts fluid to the head which is the opposite to POTS. this does trigger a reduction in blood volume, reduction in oxygen consumption, low renin, tachycardia, etc tho, all similar to POTS
Read 5 tweets
Jun 5
Folks who support the @GoodLawProject GMC case want to reduce vaccine hesitancy.

Policing what they deem misinformation and making the @gmcuk arbiters of truth will not achieve that
What will reduce vaccine hesitancy?

One thing would be to acknowledge, support, and be curious about #vaccineinjuries

I think it would do more to reduce vaccine hesitancy if the money raised went to supporting the vaccine injured.

Why?
Because no one should suffer more than acute and tolerable side effects from a vaccine.

Doctors have repeatedly dismissed and gaslit vaccine injured patients. For many reasons, but also because they dont want to "sound antivax"
Read 9 tweets
Jun 5
If you have a trial for a heterogeneous condition like #MECFS, then looking at average effects is no longer a good option to determine effectiveness.

If half improve and half get worse, we determine the intervention ineffective.

#academict
Instead we should explore *why* those who responded did respond and vice versa.

For the non responders we should then move them on to another intervention

We also need to consider poly-interventions to address multiple pathologies
This is a whole different way of trialling drug efficacy than we do now.

Folk will rightly point out the flaws in this such as the bias it introduces but fail to understand the bias current trials introduce
Read 7 tweets
Jun 1
the autonomic nervous system has a branch that does not use acetylcholine or noradrenaline as transmitters. instead it uses other things, like nitric oxide, ATP, serotonin, neuropeptide-Y, etc
link.springer.com/content/pdf/10…

some thoughts RE #MECFS #LongCovid #teamclots #dysautonomia 🧵
Nitric oxide gets released (depleted?) in ischaemia reperfusion injuries
jnnp.bmj.com/content/67/1/1

Dysmetabolism is commonly reported in #MECFS
ncbi.nlm.nih.gov/pmc/articles/P…

(Circulating) Serotonin may get depleted with platelet activation
portlandpress.com/biochemj/artic…
Appetite gets dysregulated in #LongCovid and ME, often (not always) causing lower appetite. ME may be associated with higher neuropeptide Y
pubmed.ncbi.nlm.nih.gov/21190576/
Read 5 tweets

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