title: Cardiorespiratory fitness and cardiovascular burden in chronic kidney disease.
abstract: OBJECTIVE
  Reduced functional capacity is associated with poor prognosis. In patients with chronic kidney disease the factors that contribute to low cardiorespiratory fitness are unclear. The objective of this study was to evaluate the cardiorespiratory and cardiovascular response to exercise in chronic kidney disease patients, and secondly investigate the relationships between cardiorespiratory fitness and cardiovascular burden.
  
  
  METHODS
  Cross-sectional analysis.
  
  
  METHODS
  Baseline demographic, anthropometric and biochemical data were examined in 136 patients with moderate chronic kidney disease (age 59.7±9.6yrs, eGFR 40±9ml/min/1.73m(2), 55% male, 39% with a history of cardiovascular disease, 38% diabetic and 17% current smokers). Cardiorespiratory fitness was measured as peak VO2, left ventricular morphology and function using echocardiography, central arterial stiffness by aortic pulse wave velocity and left ventricular afterload using augmentation index. Physical activity levels were assessed using the Active Australia questionnaire.
  
  
  RESULTS
  Peak VO2 (22.9±6.5ml/kg/min) and peak heart rate (148±22bpm) were 17% and 12% lower than the age-predicted values, respectively. The low fit group were significantly older, and were more likely to have type II diabetes, cardiovascular disease, a higher BMI and be less active than the high fit group (P<0.05). The independent predictors of peak VO2 were age, type II diabetes, hemoglobin level, physical activity, aortic pulse wave velocity, augmentation index, and global longitudinal strain.
  
  
  CONCLUSIONS
  In patients with chronic kidney disease, the peak VO2 and heart rate response is markedly impaired. Reduced cardiorespiratory fitness is independently associated with increased aortic stiffness, increased left ventricle afterload, poor left ventricle function and higher burden of cardiovascular risk.
authors.affiliation: School of Human Movement Studies, The University of Queensland, Australia. Electronic address: erinhowden@texashealth.org.
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Howden
authors.affiliation: School of Human Movement Studies, The University of Queensland, Australia.
authors.forename: Kassia
authors.initials: K
authors.lastname: Weston
authors.affiliation: School of Medicine, The University of Queensland, Australia.
authors.forename: Rodel
authors.initials: R
authors.lastname: Leano
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Australia.
authors.forename: James E
authors.initials: JE
authors.lastname: Sharman
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Australia.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Marwick
authors.affiliation: School of Medicine, The University of Queensland, Australia; Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Isbel
authors.affiliation: School of Human Movement Studies, The University of Queensland, Australia.
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Coombes
mesh_terms: D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000150:complications / Q000503:physiopathology; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology; D005081:Exercise Therapy; D005260:Female; D006339:Heart Rate; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D063177:Pulse Wave Analysis; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000503:physiopathology*; D012907:Smoking / Q000503:physiopathology
chemical_list: D006454:Hemoglobins
keywords: Arterial stiffness; Cardiac function; Echocardiography; Exercise physiology; Functional capacity; Physical activity