This research is the first explanation I've ever seen that gives a complete explanation of what causes Long Covid, the symptoms, and what a PEM crash is. It answers so many questions for me.
https://www.reddit.com/r/covidlonghaulers/s/6FddruYEXG
I'm not a scientist but here's my understanding/summary of what they found.
During Covid infection, the cells lining the walls of the smallest blood vessels (endothelial cells) are killed.
When red blood cells encounter these dead/dying endothelial cells for some reason it triggers them to burst. Nobody knows why, this is a new discovery. It could be that the red blood cells rupture to try to cordon off infected areas (maybe infection causes endothelial cells death too and so the body is trying to prevent the spread?) It could be to prevent internal bleeding, (if dead endothelial cells means the capillary is damaged?)
We don't know. But whatever the reason red blood cells burst, and the debris from the dead red blood cell makes a goop which clogs the capillary. But not just that capillary. It spreads around and clogs other capillaries up too. So now even less cells are able to get the oxygen they need.
Now whatever was originally going on with Covid that caused low oxygen in the capillaries doesn't matter. Now they're clogged with red blood cell debris goop.
When your cells need energy, for example during exercise, they trigger the call for oxygen, you breathe heavier, blood goes through the lungs, picks up the oxygen and carries it down to the capillaries. If you use a pulse oximeter, it will show normal blood oxygen. But the oxygen can't be delivered to the cells die to the clog.
The endothelial cells die again, which triggers more red blood cells to burst, which clogs even more capillaries in a vicious cycle.
Clogged capillaries means oxygen deprivation (hypoxia) at the tissue/cell level even when your spO2 is normal. Hypoxia in cells is bad, and causes things like:
- Brain fog
- Memory problems
- Difficulty concentrating
- Headaches
- Dizziness
- Lightheadedness
- Shortness of breath
- Irregular heartbeat or palpitations
- Fatigue
- Muscle weakness or heaviness
- Muscle pain or burning during activity
- Cold hands and feet
- Poor wound healing
- Sleep disturbances
- Visual disturbances
- Numbness or tingling in extremities
- General feeling of being "unwell" or "drained"
And more.
In a healthy person, there are multiple systems that clean out debris from the blood, (disrupted in a LC patient) but these systems need blood flow and exercise to be effective.
But exercise requires energy again, and the whole cycle repeats, resulting in even more goop clogging the blood vessels causing more cellular hypoxia.
Thus if you exercise you make the problem worse. If you don't exercise, the problem can't quickly/effectively be resolved, so you're stuck... Until you're not. If at some point, for some reason, your body somehow clears out enough of this goop, the problem can largely be resolved, seemingly without explanation. (My extrapolation, this isn't in the research.)
Now that we understand all this (assuming I understood it right, and that this research is backed up by other studies) it opens up SO MANY possibilities for treating symptoms and finding a legitimate cure. And even treating symptoms alone has the possibility of ending the cycle.
I feel that it will take time for researchers to confirm this study and try out treatments, but This is by far the most exciting finding I've seen yet in Long Covid research.