| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
In this study we clarified that spectral analysis of the heart-rate variability can be fully utilized for the estimation of the autonomic nerve activities in a bed-up test. The findings are summarized as follows :
In order to investigate the relationship between changes in blood pressure and autonomic nerve activities, bed-up experiments were performed to 13 young subjects (21.46±4.18 years old) and 18 old subjects (70.78±4.69 years old). A power spectral analysis of heart-rate variability was used for the estimation of autonomic nerve activity. The angle of sitting up in bed was changed gradually (0°, 30°, 60°). In young subjects, heart rate was not changed and blood pressure showed a little decrease. The ratio of low- to high-frequency (LF/HF), an indicator of sympathetic nerve activity, showed an increase, and the ratio of high frequency to total area (HF/TO), an indicator ofparasympathetic nerve activity, showed a decrease as the angle increases. In old subjects, both heart rate and blood pressure showed a decrease as the angle increases, whereas the frequency components were not changed.
After the subjects took a cup of iced coffee, experiments under the same condition were per formed. The young subjects could maintain their blood pressure while the old counterparts could not. Blood pressure in the old subjects showed a decrease as the angle increases, whereas the frequency components were not changed.
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