Calkins, H, Rowe, PC · Cardiology in review · 1998 · DOI
This study explored a possible connection between ME/CFS and a condition called neurally mediated hypotension, where blood pressure drops suddenly due to problems with nerve signals that control blood vessels. Researchers found that when they treated patients for this blood pressure problem, about two-thirds of ME/CFS patients felt better. While these early results were promising, the study notes that larger, more rigorous trials were needed to confirm whether this treatment truly helps.
This work was significant because it proposed a physiological mechanism that could explain ME/CFS symptoms and suggested a potentially treatable underlying cause. For patients, identifying NMH as a contributing factor could open new treatment avenues; for researchers, it provided a testable hypothesis linking autonomic dysfunction to ME/CFS pathophysiology.
This study does not prove that NMH causes ME/CFS or that treating NMH will consistently help all patients—it only documents an association in nonrandomized studies with a 67% response rate, which could reflect placebo effects or selection bias. The observational nature means causation cannot be established, and results were pending confirmation from rigorous randomized trials.
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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