A groundbreaking new study reveals why many long COVID patients experience severe fatigue and other symptoms after exercise. The findings underscore the need for these patients to pace their physical activity to avoid causing further injury.
Structural changes found in muscle cells of long COVID patients
Researchers at Radboud University in the Netherlands have discovered that the muscle cells of long COVID patients undergo structural changes that disrupt their ability to produce energy. Specifically, the mitochondria – the “power plants” within cells – fail to properly fuse together.
This impairs their function, reducing the muscles’ capacity to generate energy with oxygen. When long COVID patients attempt to exercise, their damaged muscle cells struggle to meet the heightened energy demands. This causes profound exhaustion as well as pain and other symptoms.
“What we’re showing is that in the muscles of some long COVID patients, the mitochondria structure is damaged,” said lead researcher [Dr. Carlijn Breton]. “And that leads them to not be able to produce enough energy.”
Intense exercise risks causing injury
The research team analyzed muscle biopsies from long COVID patients struggling with severe fatigue. They compared these to biopsies from healthy people and COVID patients who fully recovered.
Only the long COVID patients showed mitochondrial abnormalities. Intense exercise stresses these damaged muscle cells even further.
“It puts them at risk of cellular injury,” Dr. Breton explained. This can convert their fatigue into full-blown myalgia and myositis, which requires months of physical therapy to recover from.”
Myalgia refers to muscle pain and inflammation, while myositis indicates muscle damage.
Graded exercise therapy should not be prescribed
The findings cast further doubt on the appropriateness of graded exercise therapy (GET) for long COVID patients. GET slowly increases physical activity based on the controversial premise that patients avoid exercise due to false illness beliefs.
“This study confirms that for some long COVID patients, their fatigue has a clear biological basis and is not psychological,” said Dr. Jeremy Rossman of the University of Kent. “Pushing themselves to exercise risks injury rather than recovery.”
In light of this and [other emerging research], public health agencies in the US, UK and elsewhere have already revised guidelines to stop recommending GET. They now urge caution and activity pacing instead.
Implications for millions with long-lasting symptoms
An estimated 100 million people worldwide have developed persistent symptoms after COVID infections. Their plight has remained largely mysterious, with multiple theories but no definitive cause.
This new research is the first to offer visual evidence of structural damage in these patients’ muscles. It provides a specific biological explanation for their most troublesome symptom – extreme, unrelenting fatigue.
It transforms our understanding of long COVID,” said Dr. Rossman. “This study could be the Rosetta Stone we’ve been waiting for.”
Next steps: blood tests and drug trials
Now that they have identified this root cause, the next step is for doctors to confirm these mitochondrial abnormalities using blood tests instead of invasive biopsies. The research team is already collaborating with industry partners on developing less dangerous diagnostic procedures.
They are also screening for existing drugs that could potentially restore mitochondrial function in long COVID patients. Clinical trials of promising drug candidates could begin within the year.
In the meantime, long COVID specialists emphasize that patients should carefully pace their physical exertion to avoid overtaxing their distressed muscle cells. While not a cure, pacing helps stabilize symptoms and prevent severe relapses.
Quick facts on long COVID prevalence
| Country | % with long COVID symptoms after 3 months |
|---|---|
| UK | 21% |
| France | 17% |
| Italy | 12.6% |
| Sweden | 11% |
*Rates based on nationwide surveys. Long COVID defined as having at least one symptom persist for 3 months or more after initial COVID infection.
This research gives long COVID patients hope that specific treatments could soon be on the horizon. Their mysterious ailment likely stems from measurable damage with a known anatomical location – their muscle cell mitochondria. Successfully restoring the function of these crucial “power plants” could potentially eliminate the crushing fatigue central to long COVID.
To err is human, but AI does it too. Whilst factual data is used in the production of these articles, the content is written entirely by AI. Double check any facts you intend to rely on with another source.
