Explaining Fatigue and Post-Exertional Malaise in Long COVID and ME/CFS: From Skeletal Muscle To Exercise Immunology

Patients with long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) share debilitating, unexplained fatigue, muscle pain, and post-exertional malaise, where physical or cognitive exertion aggravates symptoms. This research investigated whether muscular changes explain this exhaustion, whether such shifts stem from physical inactivity or disease-specific mechanisms, and if muscular alterations trigger or contribute to post-exertional malaise. The thesis demonstrates that individuals with long COVID and ME/CFS display reduced aerobic exercise capacity driven by changes in active muscle tissue rather than heart or lung limitations.