title: Dynamics of heart rate variability at different ages: effect of the arm crank and cycle ergometer protocols.
abstract: BACKGROUND
  The aim of this study was to compare the behavior of heart rate variability at rest, mid-test, immediately, 5 and 10 min of recovery following the exhaustive arm crank and cycle ergometer protocols in healthy children, middle-aged and elderly subjects.
  
  
  METHODS
  Thirty-six healthy men volunteered to participate in this study and were assigned to three groups: child (N.=12), middle-aged (N.=12) and elder (N.=12). Heart rate variability was assessed by calculation of the mean R-R interval measured by Electrocardiogram at each phases.
  
  
  RESULTS
  Heart rate variability significantly decreased at mid-test, immediately and significantly increased in 5 and 10 min of recovery after both the arm crank and cycle ergometer protocols among all groups, these changes were signiﬁcantly higher in cycle ergometer compared with arm crank protocol among all age groups. Moreover, increase of heart rate variability was signiﬁcantly higher in the middle-aged than that for children and elder subjects during 5 and 10 min of recovery after cycle ergometer protocol.
  
  
  CONCLUSIONS
  Our results indicate a relationship between lowered heart rate variability and the age of the subjects. In addition, our findings suggest a clinically important effect of exhaustive physical activity in various ages after upper body work than lower body work.
authors.affiliation: Department of Sport Physiology, College of Physical Education and Sport Sciences, University of Mazandaran, Babolsar, Iran - m_ahmadian98@yahoo.com.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ahmadian
authors.forename: Valiollah
authors.initials: V
authors.lastname: Dabidi Roshan
mesh_terms: D000328:Adult; D000367:Age Factors; D001132:Arm; D002648:Child; D004562:Electrocardiography; D016552:Ergometry / Q000379:methods*; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000379:methods*; D005221:Fatigue; D006339:Heart Rate / Q000502:physiology*; D006706:Homeostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D012146:Rest