Effect of vibration magnitude and repetitive exposure on finger blood flowin healthy subjects

In order to study the effect of the magnitude of vibrations and repetitive exposure on finger blood flow, we exposed ten healthy subjects to three exp erimental conditions: (1) vibration of 3.16 m/s(2) at 60 Hz, (2) vibration of 31.6 m/s(2) at 60 Hz, and (3) no vibration, as a control. Under the expe rimental conditions, the right hand was exposed to 5-min vibration three ti mes, with intervening 5-min rests. Meanwhile, the blood flows of both middl e fingers were continuously measured with a blood flow meter based on the t hermal diffusion method. Finger blood flow was significantly decreased in b oth hands with exposure to vibrations of 3.16 m/s(2) and 31.6 m/s(2). Incre ased magnitude of vibration tended to enhance the decrease in finger blood flow in both hands, and repeated exposure to vibration had cumulative effec ts on the decrease in finger blood flow in the unexposed left hand.