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The Guardian: Long Covid and Mitochondrial Dysfunction

Many people with long Covid feel tired, unwell and in pain for lengthy periods after exercise, and researchers say they now know why. Experts say they have evidence that biological changes are to blame, such as severe muscle damage, mitochondrial problems and the presence of microclots in the body.

Nicola Davis, Science correspondent, The Guardian.

Long Covid causes changes in body that make exercise debilitating – study

Article extracts

“It’s really confirming that there is something inside the body going wrong with the disease,” said Dr Rob Wüst, an author of the study at Vrije Universiteit (Free University) Amsterdam…

Published in the journal Nature Communications, the study involved 25 patients with long Covid who reported experiencing malaise after exercising, and 21 people who had had Covid but made a full recovery. None of the participants had been hospitalised with Covid, while all had been fit and healthy before catching the virus and were of working age.

Each participant spent about 10-15 minutes on an exercise bicycle, and blood samples and skeletal muscle biopsies were taken a week before and the day after the task. While there was considerable variation between patients, on average, people with long Covid had a lower exercise capacity than healthy participants.

When the researchers analysed the biopsies taken before exercise, they found that those with long Covid had a greater proportion of white fibres in their muscles than healthy participants. These fibres have fewer power-producing structures, known as mitochondria, within their cells, and fewer capillaries.

The team also found signs that the mitochondria in people with long Covid did not work as well as those in healthy participants. Wüst said the findings partly explained why people with long Covid had a lower capacity for exercise.

Comparison of the biopsies taken before and after cycling revealed the function of the mitochondria worsened after exercise in those with long Covid, and these participants had far more tissue damage after exercising and signs of the body attempting repairs.

“That can explain, for instance, the muscle pain that these patients are experiencing after exercise,” said Wüst. He said the findings highlighted that people with long Covid should not undertake intense exercise. “It damages your muscles, it worsens your metabolism, and it can explain why you feel muscle pain and fatigue up to weeks after the exercise,” he said.

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ME Association Comment

“This new research into the cause of Long Covid provides further evidence of a significant defect in the way in which energy is created in response to exercise in battery-like structures in the muscle called mitochondria.

“There is also a very sensible warning, based on these findings, in the Guardian article against the use of exercise programmes to treat Long Covid. But it was disappointing to see that the Guardian did not appear to be aware that the same sort of muscle problem is a well recognised feature of ME/CFS.

“We already know from the muscle research that I was involved with in Oxford back in the early 1980s, which was published in The Lancet, that there is a defect in mitochondrial function in ME/CFS. Since then there have been several other research studies confirming the presence of mitochondrial dysfunction in ME/CFS and the MEA has funded research into muscle in both Oxford (Dr Karl Morten's group) and Newcastle (Professor Julia Newton's group).

“This research is summarised and referenced in the Research chapter of the MEA Clinical and Research Guide (the ‘Purple Book').”

Dr Charles Shepherd,
Trustee and
Hon. Medical Adviser
to the ME Association.
Member of the 2018-2021 NICE Guideline Committee.
Member of the 2002 Independent Working Group on ME/CFS.

Dr Charles Shepherd
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