Long COVID and skeletal muscle dysfunction

Long COVID occurs when symptoms persist for more than 3 months after acute SARS-CoV-2 infection. 

Symptoms include fatigue, brain fog, myalgia, and post-exertional malaise (PEM), which worsens with physical, mental, or cognitive exertion.

Long COVID shares many characteristics with myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS), particularly PEM, which is necessary for ME/CFS diagnosis.

Long COVID is associated with intrinsic skeletal muscle mitochondrial dysfunction, endothelial abnormalities, and a shift towards more glycolytic muscle fibers, which contribute to a lower exercise capacity.

Several potential mechanisms may explain skeletal muscle abnormalities in long COVID, including local hypoxia, deconditioning, autoimmunity, electrophysiological changes, and central fatigue.

There are no treatments for long COVID or PEM, but ongoing trials include immunoadsorption, dietary supplements, and anti-inflammatory/antiviral drugs.

https://www.cell.com/trends/endocrinology-metabolism/fulltext/S1043-2760(24)00298-4

https://sciencemission.com/Skeletal-muscle-adaptations-and-post-exertional-malaise-in-long-COVID