title: Cardiac Autonomic Adjustments During Baroreflex Test in Obese and Non-Obese Preadolescents.
abstract: BACKGROUND
  Recent studies have shown changes in cardiac autonomic control of obese preadolescents.
  
  
  OBJECTIVE
  To assess the heart rate responses and cardiac autonomic modulation of obese preadolescents during constant expiratory effort.
  
  
  METHODS
  This study assessed 10 obese and 10 non-obese preadolescents aged 9 to 12 years. The body mass index of the obese group was between the 95th and 97th percentiles of the CDC National Center for Health Statistics growth charts, while that of the non-obese group, between the 5th and 85th percentiles. Initially, they underwent anthropometric and clinical assessment, and their maximum expiratory pressures were obtained. Then, the preadolescents underwent a constant expiratory effort of 70% of their maximum expiratory pressure for 20 seconds, with heart rate measurement 5 minutes before, during and 5 minutes after it. Heart rate variability (HRV) and heart rate values were analyzed by use of a software.
  
  
  RESULTS
  The HRV did not differ when compared before and after the constant expiratory effort intra- and intergroup. The heart rate values differed (p < 0.05) during the effort, being the total variation in non-obese preadolescents of 18.5 ± 1.5 bpm, and in obese, of 12.2 ± 1.3 bpm.
  
  
  CONCLUSIONS
  The cardiac autonomic modulation did not differ between the groups when comparing before and after the constant expiratory effort. However, the obese group showed lower cardiovascular response to baroreceptor stimuli during the effort, suggesting lower autonomic baroreflex sensitivity.
authors.affiliation: Pontifícia Universidade Católica de Campinas, Campinas, SP, Brazil.
authors.forename: Mário Augusto
authors.initials: MA
authors.lastname: Paschoal
authors.affiliation: Pontifícia Universidade Católica de Campinas, Campinas, SP, Brazil.
authors.forename: Aline Carnio
authors.initials: AC
authors.lastname: Brunelli
authors.affiliation: Pontifícia Universidade Católica de Campinas, Campinas, SP, Brazil.
authors.forename: Gabriela Midori
authors.initials: GM
authors.lastname: Tamaki
authors.affiliation: Pontifícia Universidade Católica de Campinas, Campinas, SP, Brazil.
authors.forename: Sofia Serafim
authors.initials: SS
authors.lastname: Magela
mesh_terms: D000886:Anthropometry; D001341:Autonomic Nervous System / Q000503:physiopathology*; D017704:Baroreflex / Q000502:physiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D000072277:Maximal Respiratory Pressures; D009765:Obesity / Q000503:physiopathology*; D012016:Reference Values; D018709:Statistics, Nonparametric; D013997:Time Factors; D014636:Valsalva Maneuver / Q000502:physiology