Milovanovic, Branislav, Markovic, Nikola, Petrovic, Masa et al. · Biomedicines · 2025 · DOI
This study compared how the nervous system functions differently in people with Post-COVID syndrome, ME/CFS (both COVID-related and unrelated), and late-stage Lyme disease—three conditions that often feel similar but may have different causes. Researchers tested 758 patients using heart rhythm monitors, tilt tests, and blood pressure measurements to see how their bodies responded to position changes and stress. They found that Lyme disease patients showed a distinct pattern of nerve dysfunction (adrenergic failure), while Post-COVID and ME/CFS patients had different types of nervous system imbalances.
ME/CFS patients often struggle with overlapping symptoms that complicate diagnosis and treatment, making it difficult to distinguish their condition from similar post-infectious illnesses. By identifying specific patterns of nervous system dysfunction unique to each syndrome, this research could help clinicians diagnose ME/CFS more accurately and potentially guide targeted treatments. Understanding these biological differences validates that ME/CFS involves measurable physiological changes rather than purely psychiatric causes.
This cross-sectional study shows associations between these syndromes and autonomic patterns but cannot establish which came first or prove that autonomic dysfunction causes the symptoms. The study also does not track whether these ANS patterns change over time or whether they predict treatment response. Additionally, findings should not be interpreted as proof that these conditions are entirely distinct—significant overlap in autonomic dysfunction patterns suggests shared pathophysiological mechanisms.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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