title: Acute effect of resistance exercise intensity in cardiac autonomic modulation after exercise.
abstract: BACKGROUND
  Cardiac sympathovagal balance is altered after resistance exercise. However, the impact of the characteristics of resistance training in this response remains unclear.
  
  
  OBJECTIVE
  Analyze the acute effect of resistance exercise intensity for trunk and upper limbs in cardiac autonomic modulation after exercise.
  
  
  METHODS
  Fifteen young men performed three experimental sessions in random order: control (C), resistance exercise with 50% of 1-RM (E50%) and resistance exercise with 70% of 1-RM (E70%). The sessions included 05 exercises for the trunk and upper limbs performed in three sets of 12, 9 and 6 repetitions, respectively. Before and at 20 and 50 minutes after the interventions, the heart rate was measured for spectral analysis of variability.
  
  
  RESULTS
  In comparison to the values before the intervention, the RR interval and the band of high frequency (HF) increased (major changes: + 112 ± 83 ms; +10 ± 11 un, respectively, p < 0.01), while the low frequency band (LF) and LF/HF ratio decreased (major changes: -10 ± 11 pc; -2 ± 2, respectively, p < 0.01) after the session C. None of these variables changed significantly after the E50% session (p > 0.05). Compared to pre-exercise values, the RR interval and the HF band decreased (major changes: -69 ± 105 ms; -13 ± 14 un, respectively, p <0.01), while the LF band and the LF/HF ratio increased (major changes: -13 ± 14 un, 13 ± 3 14 ± 3 and un, respectively, p <0.01) after E70%.
  
  
  CONCLUSIONS
  The higher intensity of resistance exercise for trunk and upper limbs promoted, in an acute manner, greater increase in cardiac sympathovagal balance after exercise.
authors.affiliation: Escola Superior de Educação Física, Universidade de Pernambuco, Recife, PE, Brazil.
authors.forename: Aluísio Henrique Rodrigues de Andrade
authors.initials: AH
authors.lastname: Lima
authors.forename: Cláudia Lúcia de Moraes
authors.initials: CL
authors.lastname: Forjaz
authors.forename: Gleyson Queiroz de Moraes
authors.initials: GQ
authors.lastname: Silva
authors.forename: Annelise Lins
authors.initials: AL
authors.lastname: Menêses
authors.forename: Anderson José Melo Rodrigues
authors.initials: AJ
authors.lastname: Silva
authors.forename: Raphael Mendes
authors.initials: RM
authors.lastname: Ritti-Dias
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D055070:Resistance Training / Q000009:adverse effects; D013564:Sympathetic Nervous System / Q000502:physiology*; D034941:Upper Extremity / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology*; D055815:Young Adult