title: Effects of an enhanced heart rate reserve on aerobic performance in patients with a heart transplant.
abstract: OBJECTIVE
  The aim of this study was to investigate whether a high-intensity warm-up at the start of a graded, symptom-limited exercise test would enhance heart rate reserve and thus improve the aerobic performance of orthotopic heart transplant patients.
  
  
  METHODS
  Adrenal and cardiorespiratory responses were compared in 10 orthotopic heart transplant patients who performed two graded, symptom-limited exercise tests on an ergocycle.
  
  
  RESULTS
  At the start of the graded, symptom-limited exercise test, high intensity increased the norepinephrine level more than usual intensity between rest and the third minute of exercise. This higher norepinephrine level was followed by a higher heart rate response from the fourth minute of exercise. Heart rate reserve was enhanced during high-intensity exercise, without any significant change in peak oxygen uptake.
  
  
  CONCLUSIONS
  This specific warm-up enhanced heart rate reserve during a graded, symptom-limited exercise test on an ergocycle. Mechanisms more important than limited heart rate reserve are involved in the limitation of exercise tolerance in orthotopic heart transplant patients.
authors.affiliation: Laboratoire de Physiologie et de Biomécanique de l'Exercice Musculaire, Rennes, France.
authors.forename: Nathalie S
authors.initials: NS
authors.lastname: Ville
authors.forename: Alain
authors.initials: A
authors.lastname: Varray
authors.forename: Béatrice
authors.initials: B
authors.lastname: Mercier
authors.forename: Maurice
authors.initials: M
authors.lastname: Hayot
authors.forename: Bernard
authors.initials: B
authors.lastname: Albat
authors.forename: Karim
authors.initials: K
authors.lastname: Chamari
authors.forename: Christian
authors.initials: C
authors.lastname: Préfaut
authors.forename: Jacques
authors.initials: J
authors.lastname: Mercier
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D016027:Heart Transplantation / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D013647:Task Performance and Analysis; D016896:Treatment Outcome
chemical_list: D000316:Adrenergic alpha-Agonists; D009638:Norepinephrine