| Budget Amount *help |
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
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| Research Abstract |
We can catch blood vessel sounds by a stethoscope at the time of the blood pressure measurement This sound occurs because of turbulence of bloodstream in a blood vessel. We hypothesized that there might be a difference in peak frequency (PHz as follows) of blood vessel sounds by power spectral analysis according with a condition of blood vessel wall, e.g. vessel stiffness. To determine this hypothesis, we performed an experiment about 17 persons whose age were 19-63 years old as subjects. Blood vessel sounds frequency was measured at rest, and during cycle ergometer exercise at light load (20-30 w), mild load (50-60 w), and middle load (90-120 w). The PHzs of three young subjects were less than 100Hz, and one young subject was around 150Hz at rest condition. However, one subject (49 yr) showed low PHz of 93.8 Hz, and another 12 middle-aged subjects showed higher PHz that were 100-170 Hz. Among middle-aged persons, regularly exercised persons showed lower PHz than that of non- regularly exercised persons. The PHz increased by exercise with most people, but individual difference was seen in a pattern of increase. The subjects who had higher values of PHz at rest showed a tendency of higher PHz in exercise, too. For example, a subject who's PHz at rest was about 150Hz showed the value of PHz of about 250Hz, while PHzs of another subjects were 110-230 Hz. The PHzs of 4 young subjects were 110-170 Hz. There is the remainder to examine in detail about this hypothesis, these results suggested that the value of PHz by power spectral analysis may imply blood vessel stiffness at rest, and the value of PHz during exercise may amplify the difference of blood vessel condition.
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