RÉSUMÉ
Exercise is proved to have impacts on cerebral hemodynamic changes. Cerebral hemodynamic changes with exercise have been shown in an intensity-dependent from the mild intensity (about 40 % VO2max) during a graded cycling exercise. However, its association with brain activation is still unknown. In this paper, the relationship between hemodynamic and EEG-changes with exercise was examined at different intensities from low to moderate. The regional cerebral blood volume (rCBV) and the brain waves were monitored by using NIRO 300 and EEG simultaneously with exercise. Nine healthy volunteers performed a 10-minute of cycling with 30-minute rest intervals at the intensity of 20 %, 40 % and 60 % VO2max. The EEG resulted in a significant increase in their percentage changes of alpha at 20 % and 40 % VO2max and beta at 40 % and 60 % VO2max. A significant positive correlation between rCBV and beta wave was also reported (r＝0.53, P \< 0.01). These results show that changes in rCBV with exercise have a significant correlation with high frequency brain wave and implicate that exercise-enhanced rCBV in the prefrontal cortex might be associated with brain arousal.
RÉSUMÉ
Ghrelin, an endogenous ligand for the growth hormone (GH) secretagogue receptor, has been reported to induce a GH-releasing, orexigenic effect on weight gain, and adipogenic actions. It is, therefore, thought that ghrelin links the regulatory systems for growth and energy balance.We examined 25 obese children undergoing a 3-month inpatient weight reduction program for obese children based on a combination of diet and exercise therapy and evaluated the change in the serum ghrelin levels.The subjects consisted of 25 children with moderate to severe simple obesity [17 boys, 8 girls ; mean age 9.9±1.3 years, percent overweight (% overweight) 52.1±13.6%]. Height, weight, percent body fat (% BF), fat mass, fat-free mass (FFM), and serum ghrelin were measured before and after weight reduction.After therapy, body weight, % BF and fat mass had all significantly decreased (<i>p</i><0.001), while height and FFM had both significantly increased (<i>p</i><0.001 ; <i>p</i><0.05, respectively). There were no correlations between pre-therapy serum ghrelin and any of the following: initial height, weight, % overweight, % BF, fat mass, or FFM. However, after therapy, serum ghrelin levels were negatively correlated with body weight (r<sub>s</sub>=-0.544, <i>p</i><0.01). Serum ghrelin levels increased significantly from pre- to post-therapy (113.9±30.7 to 129.6±42.9 fmol/ml, <i>p</i><0.05). The rate of changes in ghrelin levels was negatively correlated with the rate of change in the % overweight (r<sub>s</sub>=-0.412, <i>p</i><0.05).These findings suggest that long-term weight reduction based on a combination of diet and exercise therapy lessens the severity of obesity and increases serum ghrelin levels in obese children.