title: Obesity and cardiac autonomic nerve activity in healthy children: Results of the toyama birth cohort study.
abstract: OBJECTIVE
  To determine the relationship between obesity and cardiac autonomic nerve activity in healthy children.
  
  
  METHODS
  16 healthy male children comprising of 9 nonobese and 7 obese subjects (body mass index > 19.1 kg/m(2)) aged 8-9 years were selected. Electrocardiograms were measured for 10 min. under controlled ventilation (0.25 Hz) in the supine position. Consecutive 256-second RR interval data were transformed by the Fast Fourier Transform method into power spectral data. Very low frequency (VLF; 0.003-0.04 Hz), low frequency (LF; 0.04-0.15Hz), high frequency (HF; 0.15-0.40Hz), and total power (TP; 0.003-0.40Hz) were calculated and transformed into a natural logarithm (In). Normalized units (nu) were also calculated as follows: LFnu=LF/(TP-VLF)x100. HFnu=HF/(TP-VLF)x100. Low/high-frequency ratio (LHR) was calculated as LF divided by HF. Unpaired t test was performed to compare the 2 groups.
  
  
  RESULTS
  TP In and HFnu, reflecting cardiac parasympathetic nerve activity, in obese children were significantly lower than those in nonobese children. In contrast, LFnu and LHF, reflecting cardiac sympathetic nerve activity, in obese children were significantly higher than those in nonobese children.
  
  
  CONCLUSIONS
  These findings suggest that obese children have higher sympathetic nerve activity and lower parasympathetic nerve activity than nonobese children.
authors: Department of Welfare Promotion and Epidemiology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, 930-0194, Toyama City, Japan, sekine@mstoyama-mpuac.jp.
authors: M
authors: M
authors: Sekine
authors: I
authors: I
authors: Izumi
authors: T
authors: T
authors: Yamagami
authors: S
authors: S
authors: Kagamimori