title: Effects of age and aerobic fitness on heart rate recovery in adult men.
abstract: BACKGROUND
  Physiological aging leads to cardiac autonomic dysfunction, which is associated with the onset and worsening of cardiovascular disease and an increased risk of death. Currently, physical exercise is considered a cardioprotective strategy and more research is needed on its benefit on cardiac autonomic function.
  
  
  OBJECTIVE
  To evaluate the autonomic control of heart rate in healthy young and middle-aged volunteers with different levels of aerobic fitness.
  
  
  METHODS
  The study included 68 volunteers, stratified for age and level of aerobic fitness. Based on aerobic fitness assessed by the submaximal exercise test, subjects were separated into two groups, good fitness and poor fitness. Assessment of cardiac autonomic control was performed based on measurements of heart rate variability at rest and heart rate recovery post-exercise. Analysis of variance with two factors was used to compare the variables investigated.
  
  
  RESULTS
  The heart rate variability is significantly lower in middle-aged volunteers than in young individuals, regardless of the aerobic fitness level (p <0.01). Higher levels of aerobic fitness in middle-aged volunteers are associated with earlier post-effort vagal reentry - rate of HR decline after 1min30s: 39.6% good aerobic fitness vs. poor 28.4% (p < 0.01).
  
  
  CONCLUSIONS
  Better levels of aerobic fitness act beneficially on the autonomic control of post-exercise heart rate, preserving the vagal reentry velocity in healthy middle-aged volunteers. However, it does not attenuate the decrease in heart rate variability due to the natural aging process.
authors: Programa de Engenharia Biomédica, COPPE, UFRJ, RJ, Brazil.
authors: Gabriela Alves
authors: GA
authors: Trevizani
authors: Paulo Roberto
authors: PR
authors: Benchimol-Barbosa
authors: Jurandir
authors: J
authors: Nadal
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000502:physiology*; D004562:Electrocardiography; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D012420:Running / Q000502:physiology; D055815:Young Adult