The release on 4 January 2024 of research ‘Muscle abnormalities worsen after post-exertional malaise in long COVID’ has given rise to much comment in the press – e.g. The Guardian who declared ‘Many people with long Covid feel tired, unwell and in pain for lengthy periods after exercise, and researchers say they now know why.’
25 patients with long Covid who reported experiencing malaise after exercising, and 21 people who had had Covid but made a full recovery were sampled. Each participant used an exercise bike for between 10-15 minutes with blood samples and skeletal muscle biopsies taken a week before and the day after the task. Overall
1. those with long Covid had a greater proportion of white fibres in their muscles than healthy participants.
2. these fibres had fewer power-producing structures (mitochondria) within their cells, and fewer capillaries.
3. that the mitochondria in people with long Covid worked less well as those in healthy participants.
4. people with long Covid had increased areas of amyloid protein in their skeletal muscles, but no evidence that these “microclots” were blocking blood vessels – as some researchers have previously proposed.
Given such post-exertional malaise it fell to i-news – to seek views on any wider applicability – “Professor Steve Griffin, of Leeds University, said the study suggests “the approach to treating conditions such as long Covid, ME and CFS [myalgic encephalomyelitis and chronic fatigue syndrome] using graded exercise regimens is entirely flawed. Moreover, it appears that over-exercising under these circumstances is actually directly damaging”.”