The roles of orthostatic hypotension, orthostatic tachycardia, and subnormal erythrocyte volume in the pathogenesis of the chronic fatigue syndrome. — CFSMEATLAS
The roles of orthostatic hypotension, orthostatic tachycardia, and subnormal erythrocyte volume in the pathogenesis of the chronic fatigue syndrome.
Streeten, D H, Thomas, D, Bell, D S · The American journal of the medical sciences · 2000 · DOI
Quick Summary
This study found that many ME/CFS patients experience a sudden drop in blood pressure and abnormal heart rate acceleration when standing up, along with symptoms like dizziness. The researchers discovered that low red blood cell volume was present in most patients tested, and that wearing inflatable compression pants could quickly reverse these standing problems. This suggests that problems with blood pooling in the legs when upright may contribute to ME/CFS symptoms.
Why It Matters
This study provides objective physiological evidence for a treatable mechanism in ME/CFS—orthostatic dysregulation linked to reduced blood volume—that could explain why patients experience worsening symptoms with prolonged standing. The finding that symptoms are correctable with external compression suggests potential non-pharmacological interventions and supports the biological basis of ME/CFS.
Observed Findings
Excessive orthostatic reductions in systolic and diastolic blood pressure during 60-minute standing in ME/CFS patients compared to controls
Orthostatic tachycardia and presyncopal symptoms in 11 of 15 ME/CFS patients versus 0 of 15 controls after standing
Subnormal circulating erythrocyte volume in 12 of the patients studied (primarily women), measured by isotopic dilution
Lower body compression with MAST garments normalized all orthostatic measurements and eliminated presyncopal symptoms within 10 minutes
Excessive elevation of plasma norepinephrine concentration after 10 minutes of standing in ME/CFS patients
Inferred Conclusions
Delayed orthostatic hypotension and tachycardia in ME/CFS are caused by excessive gravitational venous pooling
Subnormal erythrocyte volume is a frequent finding in moderate to severe ME/CFS and may contribute to its pathogenesis
Orthostatic abnormalities in ME/CFS are correctable with external lower-body compression, indicating the dysfunction is reversible
These physical abnormalities may explain presyncopal and exertional symptoms in affected patients
Remaining Questions
Are orthostatic abnormalities and reduced erythrocyte volume present in mild ME/CFS cases, or only in moderate-to-severe disease?
What This Study Does Not Prove
This study does not prove that orthostatic hypotension or reduced erythrocyte volume causes ME/CFS in all patients, only that it is frequently present in moderate-to-severe cases. It does not establish whether these findings are primary pathophysiological drivers or secondary consequences of deconditioning or disease. The small sample size (n=15) limits generalizability to the broader ME/CFS population.
Tags
Symptom:Orthostatic IntoleranceFatigue
Biomarker:Blood Biomarker
Phenotype:Severe
Method Flag:Weak Case DefinitionSmall SampleExploratory OnlySex-Stratified
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 →