title: Reduced exercise capacity in genetic haemochromatosis.
abstract: BACKGROUND
  Many patients with genetic haemochromatosis complain about fatigue and reduced physical capacity. Exercise capacity, however, has not been evaluated in larger series of haemochromatosis patients treated with repeated phlebotomy.
  
  
  METHODS
  We performed exercise echocardiography in 152 treated haemochromatosis patients (48+/-13 years, 26% women) and 50 healthy blood donors (49+/-13 years, 30% women), who served as controls. Echocardiography was performed at rest and during exercise in a semiupright position on a chair bicycle, starting from 20 W, increasing by 20 W/min. Transmitral early and atrial velocity and isovolumic relaxation time were measured at each step. Ventilatory gas exchange was measured by the breath-to-breath-technique.
  
  
  RESULTS
  Compared with healthy controls, haemochromatosis patients were more obese and less trained. More of them smoked, and 17% had a history of cardiovascular or pulmonary disease. Adjusted for training, the left ventricular function and dimensions at rest did not differ between the groups. During exercise the haemochromatosis patients obtained a significantly lower peak oxygen (O2) uptake (28.1 vs. 34.4 ml/kg per min, P<0.001). In a multiple regression analysis haemochromatosis predicted lower peak O2 uptake independently of significant contributions of sex, age, and height, as well as of systolic blood pressure and log-transformed isovolumic relaxation time at peak exercise, whereas no independent association was found with weight or physical activity (multiple R=0.74, P<0.001). Adding genotype, s-ferritin, prevalence of smoking, or history of cardiopulmonary disease among the covariates in subsequent models did not change the results.
  
  
  CONCLUSIONS
  Genetic haemochromatosis, even when treated with regular phlebotomy, is associated with lower exercise capacity independently of other covariates of exercise capacity.
authors.affiliation: Department of Heart Disease, Haukeland University Hospital, University of Bergen, Norway. einar.davidsen@helse-bergen.no
authors.forename: Einar Skulstad
authors.initials: ES
authors.lastname: Davidsen
authors.forename: Knut
authors.initials: K
authors.lastname: Liseth
authors.forename: Per
authors.initials: P
authors.lastname: Omvik
authors.forename: Tor
authors.initials: T
authors.lastname: Hervig
authors.forename: Eva
authors.initials: E
authors.lastname: Gerdts
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D017079:Exercise Tolerance; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006432:Hemochromatosis / Q000000981:diagnostic imaging / Q000235:genetics / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000503:physiopathology; D010101:Oxygen Consumption; D018962:Phlebotomy; D012107:Research Design; D014463:Ultrasonography; D016276:Ventricular Function