[Effects of local vibration exposure on the finger blood flow (author's transl)]

The purpose of the present study was to clarify the physiological response of peripheral blood vessels when some vibrational stimuli were given to five healthy young men (21-22) continuously and intermittently. The vasoreaction was observed on each subjects after the exposure to vibration at frequencies 18, 32, 64 and 125 Hz with acceleration level at 5 g (peak value). In the pulse wave height of left and right arms, a specified tendency was not found while a larger variation was observed. After continuous exposures, pulse wave propagation velocity at the left arm showed a decreasing tendency at lower frequencies, but in the right arm, such a tendency did not appear. After intermittent exposures, it showed decreasing tendencies at both the left and righ arms, but such remarkable decreases were not observed as was seen at the left arm after continuous exposure. Variation analysis on the pulse wave showed that the propagation velocity was related significantly (p less than 0.01) to the subject and to the frequency during continuous and intermittent exposures of the left and right arms. These results indicate that the lower frequency is one of the factors which cause the vibrational disease, and there was a person who is liable to vibrational disease. When compared with the intermittent vibration exposure, the continuous vibration exposure produced significantly lower pulse wave propagation velocities in the left arm. This finding indicates that the intermittent vibration relieves an accumulation of the effects by vibration.