title: Ability to work in anaerobic condition is associated with physical performance on the six-minute walk test in older patients receiving cardiac rehabilitation.
abstract: OBJECTIVE
  During maximal incremental exercise, the ability to work in the anaerobic condition, expressed by the respiratory exchange ratio, is associated with physical performance. Further, peak respiratory exchange ratio is regarded as the best non-invasive measure of a patient's actual exercise effort. This study examined whether ability to work in the anaerobic condition is also associated with physical performance in submaximal constant work rate exercise.
  
  
  METHODS
  A total of 75 older patients (51 men, 24 women), mean age 71.1 years (standard deviation 6.7 years), who had recently undergone cardiac surgery, performed cardiopulmonary exercise testing in a 6-min walk test before and after rehabilitation.
  
  
  RESULTS
  The distance walked, steady-state oxygen uptake, carbon dioxide output and respiratory exchange ratio increased significantly after rehabilitation (p < 0.001 for all). In multivariable models predicting the distance walked before and after rehabilitation, higher steady-state respiratory exchange ratio was independently associated with longer distance (p < 0.001 for both).
  
  
  CONCLUSIONS
  In older patients receiving post-acute cardiac rehabilitation the ability to work in the anaerobic condition is associated with physical performance in submaximal constant work rate exercises. Thus the steady-state respiratory exchange ratio might be regarded as a measure of the patient's actual exercise effort. This information may prove useful in customizing exercise prescription and assessing the effects of rehabilitation.
authors.affiliation: Cardiac Rehabilitation Unit, Don Gnocchi Foundation, 50143 Florence, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Pasquini
authors.forename: Federica
authors.initials: F
authors.lastname: Vannetti
authors.forename: Raffaele
authors.initials: R
authors.lastname: Molino-Lova
mesh_terms: D000368:Aged; D006348:Cardiac Surgical Procedures / Q000534:rehabilitation*; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D016138:Walking / Q000502:physiology; D014937:Work / Q000502:physiology