title: Initial and final exercise heart rate transients: influence of gender, aerobic fitness, and clinical status.
abstract: OBJECTIVE
  To compare the independent and additive data provided by initial and final heart rate (HR) exercise transients, and to analyze both according to gender, aerobic fitness, clinical status, and medication usage.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Exercise medicine clinic.
  
  
  METHODS
  A total of 544 subjects (363 men) with a mean (+/- SD) age of 50 +/- 14 years (age range, 10 to 91 years), including asymptomatic and coronary artery disease patients.
  
  
  RESULTS
  HR transients were obtained from the following two exercise protocols: 4-s exercise test (4sET) followed by a maximal cardiopulmonary cycling exercise test (CPET). The initial HR transient was represented by the cardiac vagal index (CVI), which was obtained by the 4sET, and the final transient (ie, HR recovery [HRR]) was determined by the following equation: CPET maximal HR - the 1-min postexercise HR. Transients were modestly related (r = 0.22; p < 0.001) when adjusted for age, aerobic fitness, clinical status, and negative chronotropic action drug usage. The transients were unrelated to gender (vs CVI, p = 0.10; vs HRR, p = 0.15). Subjects with a measured maximum oxygen uptake (VO2max) exceeding 100% of the predicted maximal aerobic power showed higher CVIs than those in less aerobically fit subjects (VO2max < 50% subgroup, p = 0.009; VO2max < 75% subgroup, p = 0.034). Both transient results differed for asymptomatic and cardiac subjects (CVI, 1.32 +/- 0.02 vs 1.42 +/- 0.02, respectively [p = 0.001]; HRR, 33 +/- 1 beats/min (bpm) vs 37 +/- 1 bpm, respectively [p = 0.009]).
  
  
  CONCLUSIONS
  The initial and final HR transients were modestly related, suggesting a potentially complementary clinical role for both measurements in the assessment of autonomic function in patients with coronary artery disease. Although both HR transients tended to behave similarly under the influence of several variables, the initial HR transient, measured during 4sET, was more likely to discriminate distinct subgroups compared with the final HR transient.
authors.affiliation: Physical Education Graduate Program, Gama Filho University, Rio de Janeiro, Brazil.
authors.forename: Djalma Rabelo
authors.initials: DR
authors.lastname: Ricardo
authors.forename: Marcos Bezerra
authors.initials: MB
authors.lastname: de Almeida
authors.forename: Barry A
authors.initials: BA
authors.lastname: Franklin
authors.forename: Claudio Gil S
authors.initials: CG
authors.lastname: Araújo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015986:Confounding Factors, Epidemiologic; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology; D012189:Retrospective Studies; D012737:Sex Factors