E2 ModeratePreliminaryPEM not requiredCross-SectionalPeer-reviewedMachine draft
Standard · 3 min
An assessment of fatigue in patients with postural orthostatic tachycardia syndrome.
Wise, Shelby, Ross, Amanda, Brown, Abigail et al. · Journal of health psychology · 2017 · DOI
Quick Summary
This study looked at fatigue in people with POTS (postural orthostatic tachycardia syndrome), a condition that shares many symptoms with ME/CFS. Researchers asked 138 young people with POTS to describe their fatigue and brain fog using questionnaires. They found that fatigue comes in multiple forms and that people with POTS fall into two groups: those with mild symptoms and those with severe symptoms, with the severe group experiencing much worse brain fog and activity limitations.
Why It Matters
Since ME/CFS and POTS share overlapping symptoms including severe fatigue, understanding how fatigue manifests in POTS may illuminate similar mechanisms in ME/CFS and help clinicians better stratify patients into subgroups for more targeted treatment. Identifying distinct fatigue phenotypes could enable personalized management approaches and improve research design by accounting for symptom heterogeneity.
Observed Findings
Exploratory factor analysis of the Fatigue Types Questionnaire produced a three-factor solution for fatigue expression in POTS.
Cluster analysis identified two distinct severity groups: a high-severity cluster and a low-severity cluster.
Participants in the high-severity cluster reported significantly greater brain fog at multiple time points during the survey.
The high-severity cluster reported greater activity impairment and more frequent, severe, and debilitating symptoms from both POTS and brain fog.
Fatigue in POTS appears to function as a multidimensional construct rather than a unitary symptom.
Inferred Conclusions
Individuals with POTS experience fatigue as a multidimensional phenomenon, consistent with similar observations in chronic fatigue syndrome.
Patients with POTS can be meaningfully stratified into severity-based subgroups based on their fatigue profile and associated symptoms.
Brain fog severity co-varies with overall POTS symptom burden and activity impairment, suggesting these constructs may be related.
Symptom heterogeneity within POTS warrants consideration of patient subtypes in clinical and research contexts.
Remaining Questions
What are the biological or physiological mechanisms driving multidimensional fatigue and brain fog in POTS?
What This Study Does Not Prove
This study does not demonstrate that POTS causes ME/CFS or vice versa, nor does it identify the biological mechanisms underlying multidimensional fatigue in either condition. The cross-sectional design cannot establish causality, and findings in a young POTS population may not generalize to ME/CFS patients or older age groups. The study does not define or measure post-exertional malaise specifically.
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 →