title: Exercise training and autonomic nervous system activity in obese individuals.
abstract: OBJECTIVE
  This study was designed to investigate the effects of 12 wk of exercise training on autonomic nervous system (ANS) in 18 obese middle-aged men (N = 9) and women (N = 9) (age: 41.6 +/- 1.2 yr; BMI: 27.3 +/- 0.4 kg x m(-2); %fat: 29.6 +/- 1.3%, mean +/- SE).
  
  
  METHODS
  Each subject participated in an aerobic exercise training at anaerobic threshold (AT), consisting of 30 min/session, 3 times/wk, for 12 consecutive weeks. The ANS activities were assessed by means of power spectral analysis of heart rate variability (HRV) at resting condition before, at 5 wk, and after the exercise program.
  
  
  RESULTS
  The exercise training resulted in a significant decrease in body mass, BMI, and % fat (P < 0.01) but not in lean body mass (P > 0.05) together with a significant increase in the AT VO2 (P < 0.01). Our power spectral data indicated that there were significant increases in the low-frequency component associated with the sympathovagal activity (0.03--0.15 Hz, 348.5 +/- 66.8 vs 694.7 +/- 91.5 ms(2), P < 0.01), the high-frequency vagal component (0.15--0.4 Hz, 146.3 +/- 30.4 vs 347.7 +/- 96.5 ms(2), P < 0.05), and the overall autonomic activity as evaluated by total power (0.03--0.4 Hz, 494.8 +/- 88.5 vs 1042.4 +/- 180.9 ms(2), P < 0.01) of HRV after the training.
  
  
  CONCLUSIONS
  Twelve weeks of exercise training has significantly improved both the sympathetic and parasympathetic nervous activities of the obese individuals with markedly reduced ANS activity, suggesting a possible reversal effect of human ANS functions. These favorable changes may also have an influence on the thermoregulatory control over the obesity.
authors.affiliation: Laboratory of Applied Physiology, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Amano
authors.forename: T
authors.initials: T
authors.lastname: Kanda
authors.forename: H
authors.initials: H
authors.lastname: Ue
authors.forename: T
authors.initials: T
authors.lastname: Moritani
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D005081:Exercise Therapy; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications / Q000628:therapy*; D016896:Treatment Outcome