title: Effects of progressive exercise during phase I cardiac rehabilitation on the heart rate variability of patients with acute myocardial infarction.
abstract: OBJECTIVE
  Heart rate variability (HRV) decreases after an acute myocardial infarction (AMI) due to changes in cardiac autonomic balance. The purpose of the present study, therefore, was to evaluate the effects of a progressive exercise protocol used in phase I cardiac rehabilitation on the HRV of patients with post-AMI.
  
  
  METHODS
  Thirty-seven patients who had been admitted to hospital with their first non-complicated AMI were studied. The treated group (TG, n=21, age=52±12 years) performed a 5-day programme of progressive exercise during phase I cardiac rehabilitation, while the control group (CG, n=16, age=54±11 years) performed only respiratory exercises. Instantaneous heart rate (HR) and RR interval were acquired by a HR monitor (Polar®S810i). HRV was analysed by frequency domain methods. Power spectral density was expressed as normalised units (nu) at low (LF) and high (HF) frequencies, and as LF/HF.
  
  
  RESULTS
  After 5 days of progressive exercise, the TG showed an increase in HFnu (35.9±19.5 to 65.19±25.4) and a decrease in LFnu and LF/HF (58.9±21.4 to 32.5±24.1; 3.12±4.0 to 1.0±1.5, respectively) in the resting position (p<0.05). No changes were observed in the CG.
  
  
  CONCLUSIONS
  A progressive physiotherapeutic exercise programme carried out during phase I cardiac rehabilitation, as supplement to clinical treatment increased vagal and decreased sympathetic cardiac modulation in patients with post-AMI.
authors.affiliation: Department of Physiotherapy, Federal University of São Carlos, São Carlos, SP, Brazil.
authors.forename: Michele D B
authors.initials: MD
authors.lastname: Santos-Hiss
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Melo
authors.forename: Victor R
authors.initials: VR
authors.lastname: Neves
authors.forename: Flávio C
authors.initials: FC
authors.lastname: Hiss
authors.forename: Roberto M M
authors.initials: RM
authors.lastname: Verzola
authors.forename: Ester
authors.initials: E
authors.lastname: Silva
authors.forename: Audrey
authors.initials: A
authors.lastname: Borghi-Silva
authors.forename: Alberto
authors.initials: A
authors.lastname: Porta
authors.forename: Nicola
authors.initials: N
authors.lastname: Montano
authors.forename: Aparecida Maria
authors.initials: AM
authors.lastname: Catai
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology* / Q000534:rehabilitation*