OBJECTIVES: This study investigated whether reductions in finger blood flow (FBF) during and after vibration are similarly dependent on the magnitude and duration of the vibration. METHODS:FBF on the left and right hand was measured every minute during, and for 1 h following, exposure of the right hand to one of three magnitudes of 125-Hz sinusoidal vibration (0, 22, or 88 ms(-2) rms) for one of two durations (7.5 or 15 min). Each of five experimental sessions was comprised of five periods: (i) no force and no vibration (5 min), (ii) 2-N force and no vibration (5 min), (iii) 2-N force and vibration (7.5 or 15 min), (iv) 2-N force and no vibration (5 min), and (v) no force and no vibration (60 min). RESULTS: Vibration reduced FBF in the exposed and unexposed hands, both during and after vibration. With increased magnitude of vibration, there was increased vasoconstriction in all fingers during and after exposure, and longer recovery times after vibration exposure. With increased duration of vibration, there were no changes in vascular responses during exposure but increased vasoconstriction after exposure and prolonged recovery times. With the greater vibration magnitude, the reduction in FBF during exposure was correlated with the time taken to recover after exposure. CONCLUSIONS: Subjects with greater reduction in blood flow during vibration exposure also have stronger and longer vasoconstriction during subsequent recovery. The correlation between vascular changes during and after vibration exposure suggests similar mechanisms control FBF during and after vibration exposure.
RCT Entities:
OBJECTIVES: This study investigated whether reductions in finger blood flow (FBF) during and after vibration are similarly dependent on the magnitude and duration of the vibration. METHODS: FBF on the left and right hand was measured every minute during, and for 1 h following, exposure of the right hand to one of three magnitudes of 125-Hz sinusoidal vibration (0, 22, or 88 ms(-2) rms) for one of two durations (7.5 or 15 min). Each of five experimental sessions was comprised of five periods: (i) no force and no vibration (5 min), (ii) 2-N force and no vibration (5 min), (iii) 2-N force and vibration (7.5 or 15 min), (iv) 2-N force and no vibration (5 min), and (v) no force and no vibration (60 min). RESULTS: Vibration reduced FBF in the exposed and unexposed hands, both during and after vibration. With increased magnitude of vibration, there was increased vasoconstriction in all fingers during and after exposure, and longer recovery times after vibration exposure. With increased duration of vibration, there were no changes in vascular responses during exposure but increased vasoconstriction after exposure and prolonged recovery times. With the greater vibration magnitude, the reduction in FBF during exposure was correlated with the time taken to recover after exposure. CONCLUSIONS: Subjects with greater reduction in blood flow during vibration exposure also have stronger and longer vasoconstriction during subsequent recovery. The correlation between vascular changes during and after vibration exposure suggests similar mechanisms control FBF during and after vibration exposure.
Authors: Brian D Curry; James L W Bain; Ji-Geng Yan; Lin Ling Zhang; Mark Yamaguchi; Hani S Matloub; Danny A Riley Journal: Muscle Nerve Date: 2002-04 Impact factor: 3.217