Autonomic function and serum erythropoietin levels in chronic fatigue syndrome Journal of Psychosomatic Research, Volume 56, Issue 2, February 2004, Pages 179-183 Andrea S. Winkler [a], Dorothy Blair [b], Joanne T. Marsden [c], Timothy J. Peters [c], Simon Wessely [b, d] and Anthony J. Cleare [b, d, e,* ] Affiliations: [a] Department of Medicine, GKT School of Medicine, London, UK [b] Department of Psychological Medicine, GKT School of Medicine, London, UK [c] Department of Clinical Biochemistry, GKT School of Medicine, London, UK [d] Division of Psychological Medicine, The Institute of Psychiatry, London, UK [e] National Affective Disorders Unit, Maudsley Hospital, London, UK [*] Corresponding author. Section of Neurobiology of Mood Disorders, Division of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, , London SE5 9RJ, , UK. Tel.: +44-207-848-5130; fax: +44-207-848-5129 Email: mailto:a.cleare@iop.kcl.ac.uk . Received 12 November 2002; accepted 10 June 2003. Available online 4 March 2004. Abstract Objective: Given previous findings, we wished to investigate whether there was evidence of autonomic dysfunction in patients with chronic fatigue syndrome, and whether this could be related to reduced erythropoietin levels and altered red blood cell indices. Methods: We assessed autonomic function and analysed blood parameters (including erythropoietin) in 22 patients with chronic fatigue syndrome who were medication-free and without comorbid depression or anxiety. Results were compared to 23 iron-deficiency anaemia patients and 18 healthy individuals. Results: Autonomic testing in patients with chronic fatigue syndrome yielded a significantly greater increase in heart rate together with a more pronounced systolic blood pressure fall on standing compared to healthy individuals. Heart rate beat-to-beat variation on deep breathing and responses to the Valsalva manoeuvre were normal. Two of 22 patients with chronic fatigue had mild normochromic normocytic anaemia with normal ferritin, vitamin B12 and folate levels. Serum erythropoietin levels were within reference range. Conclusion: Some autonomic dysfunction is present in chronic fatigue syndrome (CFS) patients; the explanation remains uncertain, but could relate to cardiovascular deconditioning. There were no major haematological, biochemical or immunological abnormalities in these patients. Author Keywords: Chronic fatigue syndrome; Erythropoietin; Autonomic dysfunction; Anaemia Copyright © 2004 Elsevier Inc. All rights reserved.