title: Short-term heart rate variability in asthmatic obese children: effect of exhaustive exercise and different humidity conditions.
abstract: OBJECTIVE
  Asthmatic obese children experience changes in functional capacity and autonomic control. Previous heart rate variability (HRV) studies were based on 24-hour recordings, little research has been conducted on the short-term HRV in asthmatic obese children, primarily during physical effort indifferent environmental humidity conditions. The aim of this study was to evaluate the effect of aerobic activity on short-term HRV in asthmatic obese children under two different environmental humidity conditions.
  
  
  METHODS
  Ten obese boys with mild asthma as experimental group and 15 obese healthy boys with the same conditions were involved as a control group. Protocol included progressive and exhaustive aerobic activities on a calibrated ergometer pedal bicycle in two various environmental humidity 35±5% and 65±5%. HRV was measured by PADSY MEDSET Holter monitoring device during three phases; pre-test, mid-test and post-test. Then, short-term HRV was assessed from calculation of the mean R-R interval measured on HRV at each phases.
  
  
  RESULTS
  HRV significantly decreased at mid-test and post-test among asthmatic and health children. However, the aforesaid changes were signiﬁcantly higher in the asthmatic than health children following. Moreover, decrease of short-term HRV was signiﬁcantly greater in the 35±5% than 65±5% environmental humidity.
  
  
  CONCLUSIONS
  Our findings suggest from the autonomic standpoint, asthmatic and non-asthmatic children respond differently to exhaustive exercise induced stress. Aerobic exercise at an environment with high humidity compared with the low humidity appears to have additional benefits on short-term HRV in that it enhances the parasympathetic and autonomic modulation of the heart in asthmatic obese children.
authors.affiliation: Department of Sport Physiology, College of Physical Education and Sport Science, University of Mazandaran, Babolsar, Iran - vdabidiroshan@yahoo.com.
authors.forename: K
authors.initials: K
authors.lastname: Rezvan
authors.forename: V
authors.initials: V
authors.lastname: Dabidi Roshan
authors.forename: S A
authors.initials: SA
authors.lastname: Mahmudi
mesh_terms: D001249:Asthma / Q000150:complications / Q000503:physiopathology*; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006813:Humidity; D008297:Male; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D010807:Physical Endurance / Q000502:physiology*; D011379:Prognosis; D013997:Time Factors