title: Autonomic function and serum erythropoietin levels in chronic fatigue syndrome.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Medicine, Division of Psychological Medicine, GKT School of Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 9RJ, UK.
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Winkler
authors.forename: Dorothy
authors.initials: D
authors.lastname: Blair
authors.forename: Joanne T
authors.initials: JT
authors.lastname: Marsden
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Peters
authors.forename: Simon
authors.initials: S
authors.lastname: Wessely
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Cleare
mesh_terms: D000328:Adult; D000418:Albumins / Q000378:metabolism; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D003404:Creatinine / Q000097:blood / Q000652:urine; D004921:Erythropoietin / Q000097:blood*; D015673:Fatigue Syndrome, Chronic / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014636:Valsalva Maneuver; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D000418:Albumins; D004921:Erythropoietin; D003404:Creatinine; D014805:Vitamin B 12