Okamoto, Luis E, Raj, Satish R, Peltier, Amanda et al. · Clinical science (London, England : 1979) · 2012 · DOI
This study looked at patients with POTS (a condition where heart rate increases too much when standing) to see how many also have ME/CFS and whether they are different from POTS patients without ME/CFS. The researchers found that most POTS patients experience severe fatigue, and about two-thirds also meet ME/CFS criteria. Those with both conditions had stronger heart rate increases when standing and signs of greater stress hormone activity.
This research clarifies the relationship between ME/CFS and POTS, two frequently co-occurring conditions that are often misunderstood. By identifying increased sympathetic nervous system activation in CFS-POTS patients, it suggests potential treatment targets (sympathetic modulation) that could benefit patients with both conditions.
This study does not establish that sympathetic hyperactivation *causes* the fatigue or ME/CFS symptoms—only that these markers are associated. The cross-sectional design cannot determine whether CFS-POTS represents a truly distinct entity or merely the severe end of the POTS spectrum. The findings do not explain why some POTS patients develop ME/CFS while others do not.
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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