title: Overweight and reduced heart rate variability in British children: an exploratory study.
abstract: OBJECTIVE
  To investigate the associations between heart rate variability (HRV) and weight status in children.
  
  
  METHODS
  Following ethics approval, 182 children (87 males, 95 females) aged between 6 and 11 years old (Mean (SD) age 9.1 (1.4) years) were assessed for height and body mass from which body mass index (BMI, kg/m(2)) was calculated. Data were collected in Central England, March-June 2011. Resting HRV was assessed in the supine position. Time domain (RMSSD and pNN50) and frequency domain (HF and LF power (ms(2)), LF/HF ratio) measures of HRV were calculated. Pearson correlations were used to assess the associations between BMI and HRV parameters. Differences in HRV parameters according to gender or weight status were analysed using t-tests.
  
  
  RESULTS
  BMI was significantly and inversely related to RMSSD (r=-0.23, p=0.001) and pNN50 (r=0.20, p=0.008) but not frequency domain measures of HRV (p>0.05). Overweight/obese children demonstrated lower HF power compared to normal weight children (p=0.02). RMSSD and pNN50 were significantly lower in overweight/obese children compared to normal weight children (p<0.05). Age was associated with changes in Mean R-R and RMSSD (p<0.05).
  
  
  CONCLUSIONS
  This exploratory study suggests that HRV is reduced in overweight/obese children.
authors.affiliation: Department of Biomolecular and Sport Sciences, Coventry University, Coventry, UK. s.birch@coventry.ac.uk
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Birch
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Duncan
authors.forename: Craig
authors.initials: C
authors.lastname: Franklin
mesh_terms: D001341:Autonomic Nervous System; D015992:Body Mass Index; D002648:Child; D004739:England; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology; D050177:Overweight / Q000503:physiopathology*