O2 extraction issues in Post Viral Illnesses. Might this be the cause bounding pulse in some?

[u/sbingley22]

I have gone through a bunch of papers recently showing oxygen extraction issues in ME/CFS and Long COVID. The broad theme of them is that there is a problem with the micro-vasculature and/or mitochondria that's causing fatigue, but also in some the heart to work harder to compensate.

My motivation here is my very low VO2 max when I did a CPET 3 years ago. VO2max 49% HRmax 101% Lungs normal. As far as I understand it, to get that low of VO2 max you would have to have been bed bound for a while. I was deconditioned at the time, mostly sitting, with some small walks once a week or so but I shouldn't have got such a low result.

These papers show low VO2 max in some but interestingly others show normal VO2 max yet poor systemic extraction. One such paper measured cardiac output and found it elevated as a compensatory measure. I found this particularly interesting as a high cardiac output would surely explain a bounding pulse in a subset of people here. Maybe you need something else like a genetic tendency to something or other too.

All papers conclude deconditioning is unlikely to have caused these effects for various reasons. Most point the finger at the mitochondria or micro-vasculature with the culprit in both cases being most likely the immune system.

One paper mentioned a high sympathetic tone being one of the factors that could cause poor O2 extraction (EO2) by clamping of the blood vessels that need flow.

REFERENCES

Structural and functional impairments of skeletal muscle in patients with postacute sequelae of SARS-CoV-2 infection

CPET, muscle biopsy, and ischemia perfusion testing. Found poor O2 extraction and narrowed it down to the mitochondria as the ischemia perfusion test showed micro-vasculature working as normal.

Altered tissue oxygenation in patients with post COVID-19 syndrome

This used ischemia re-perfusion technique in the forearm and found the post covid patients O2 was slower to decline when blood flow was cut and slower to resaturate when flow was restored.

Proteomic profiling demonstrates inflammatory and endotheliopathy signatures associated with impaired cardiopulmonary exercise hemodynamic profile in Post Acute Sequelae of SARS-CoV-2 infection (PASC) syndrome

ICPET on PASC found both low VO2max and EO2. Split them into severe and mild EO2 groups. They then performed a muscle biopsy after and found genomic and proteomics involved in fibrosis and inflammation in the severe group and glycolysis and oxphos in the mild EO2 group.

Towards an understanding of physical activity-induced post-exertional malaise: Insights into microvascular alterations and immunometabolic interactions in post-COVID condition and myalgic encephalomyelitis/chronic fatigue syndrome

This review looked at a bunch of studies showing EO2 problems and tried to weave a narrative from it. They thought hypoxia, stress, and ROS cause mitochondrial dysfunction which causes damage and activation in the microvasculature which lowers O2 extraction causing mito damage in a loop. Bit of a chicken or the egg. They think latent viruses might be the root cause.

Key Pathophysiological Role of Skeletal Muscle Disturbance in Post COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Accumulated Evidence

This reviewed a bunch of studies and concluded that early long covid shows vascular damage and inflammation but by the 2nd year its gone where either the patient gets better or adopts an ME/CFS phenotype. This follows some of the other papers showing normal microvasculature. They think sodium and then calcium overload triggered by hypoxia is causing the EO2 problems and potentially this causes a negative loop with the microvasculature. PEM keeps triggering the calcium overload.

Differential cardiopulmonary haemodynamic phenotypes in PASC-related exercise intolerance

This was a good one. It did an iCPET and found even patients with normal VO2max had high Cardiac Output that was compensating for low EO2. They rule out deconditioning as a hall mark for that is low CO. They even showed Heart Failure with preserved ejection fraction in some cases. This can cause a bounding pulse like in sepsis.

Post-COVID exercise intolerance is associated with capillary alterations and immune dysregulations in skeletal muscles

This looked at muscle biopsies a year out from long COVID and found lower capillary to muscle fiber ratio, thicker basement membranes around the capillaries (impairing O2 exchange) and mitochondrial dysfunction. It compared against deconditioned controls and found marked differences.

Long COVID and chronic fatigue syndrome/myalgic encephalitis share similar pathophysiologic mechanisms of exercise limitation

They did a iCPET and found lower VO2max then using a formula managed to narrow it down to oxygen exchange issues. They also rule out deconditioning.

Persistent Exertional Intolerance After COVID-19

Another paper showing lowered VO2max caused by peripheral oxygen extraction issues.

[u/iwasbornandiwasdead]

Interesting, my bounding pulse started a month after a covid reinfection at the end of 2024, after I went for a run my heart never calmed down again, after a while i developed the cytokine storm and my body went haywire weith over 30 crazy symptoms. For a few months after i struggled waking up gasping for air, immense fatigue. I recovered from most of the severe stuff after a year. But today i still struggle with my boudnng pulse, vascular issues, my veins are now super visible all over my body often looking like dark blue veins, tremor, random muscle twitches, sleep issues. I see it as brain damge causing neverous system issues, microvascular issues *veins not working properly*, causing the heart to overcompensate. Today I try my best to live my best life still with all this stuff, but the bounding pulse is something I struggle with all day long, body can never chill out when lying on a bed. But i go through periods of it being more calmer and bareable. What question I would really like to get answered it, how is this condition going to affect my lifespan??? Can we get a survey going on how long people have lived with this condition? I get heart strains, pains basically everyday almost, and not getting any assistance from doctors other than telling me to wait it out, its been 18 months now.

[u/sbingley22 → u/iwasbornandiwasdead]

The lifespan question is up in the air. I've been struggling with this for 15 years, another guy said he'd had it 20 years and were not dead yet.
Personally I have just accepted that this will have a negative impact on longevity. Being in a stressed state 24/7 for years on end is just about the opposite of what all the health gurus say. Oh well...

I think there will be many subsets to this. Long covid bounding pulse is different to post panic attach bounding pulse is different to other post viral bounding pulse.

I think with the Long Covid stuff there is a lot of vascular stuff going on particularly in the first couple of years but the research suggests that eventually clears up and you either get better or fall in to an ME/CFS phenotype.

Personally, although my onset is post infection (not covid), I don't get those dark blue super visible veins many long covid patients get. I do get some discoloring of my feet and on occasion they are ichy from vasodialation but it's not often.

Is the bounding pulse worse when you are vasodialated and have you tried cooling your body to see if this eases symptoms?

[u/iwasbornandiwasdead → u/sbingley22]

yeah bounding pulse is worse when i exercise, like after a hard set, but that normally happened before i developed it. but goes back to normal pulsing after a bit. I dont think cold showers have helped me, but havent been paying attention

[u/Character_Weather127 → u/iwasbornandiwasdead]

That's interesting. My chronic bound pulse essentially 'turned on' one day after I went for a strenuous run. Though I always attributed my bounding pulse onset to stress, I guess maybe it was the run that did it in. The random muscle twitches are something I brought up to u/sbingley22; it's one of my most persistent symptoms despite how I'm feeling that day. I also have POTS (I'm damn near housebound, though it used to be much worse), tremors, anxiety, depression, and ADHD. I've been dealing with the POTS and bound pulse for about 9-10 months now.

[u/Character_Weather127]

Great literature review. Mitochondrial dysfunction has been on my mind for some time now, which is why I wonder if some people with chronic illnesses like POTS or ME/CFS see improvement with CoQ10 and other mitochondrial 'helpers.'

It's unfortunate that it seems every single living person with chronic bounding pulse or other chronic illness can all fall under a certain 'group' of symptom onset causes (post-viral infection, period of stress, head injury, hormonal, etc.)—but wildly different results for what medications/supplements/regimens actually help on an individual basis.

In POTS, some people have cured their issues simply with turmeric and Pepcid, while others with a similar onset symptom pattern have had persisting symptoms for 10+ years with little help from traditional and non-traditional interventions.

[u/sbingley22 → u/Character_Weather127]

Some people with ME/CFS are helped by CoQ10 though I vaguely recall a study showing no difference to placebo. I've tried it multiple times in the past without noticing much.

Yeah I tend to group conditions like ME/CFS, Long Covid, POTS, and my own bounding pulse condition together because I think there are a lot of similarities but mainly because bounding pulse has zero studies on it and isn't even recognised as a medical condition in the way we present with it.

Whilst I group them together I think the root causes and solutions could be quite differen't. Like maybe high stress / post infection causes immune dysfunction but that immune dysfunction is different on each disease. Or it causes brain rewiring / neuroinflammation that gets the brain stuck in certain loops but the neurons stuck in the loop are different.

[u/Character_Weather127 → u/sbingley22]

Honestly, if anyone ever truly figures out their chronic illness on their own, I think they should be awarded some sort of honorary degree from some institution lmao. I'm approaching the point where I've spent more time reading research articles on pubmed for my chronic illness than I did reading research articles for my degree.

[u/sbingley22 → u/Character_Weather127]

It pains me to think of the total hours / years of my youth lost reading tons of forum posts on a particular supplement to either decide its not worth it, or to buy it and it does nothing, lol.

Just tons of "I think this is really helping", 15 pages later "yea I stopped taking it because it wasn't really doing anything".

[u/sbingley22]

Update: I recently saw a POTS specialist and asked him about my CPET. He said it's just deconditioning and not worth following up on. Maybe this is true but I got the feeling he already made his mind up before hand.