Original article

Scand J Work Environ Health 1998;24(2):130-137    pdf


Duration of acute exposures to vibration and finger circulation

by Bovenzi M, Lindsell CJ, Griffin MJ

Objectives This study investigated changes in finger circulation after different durations of exposure to hand-transmitted vibration.

Methods Finger skin temperature (FST), finger blood flow (FBF), and finger systolic blood pressure (FSBP) were measured, the latter two by strain gauge plethysmography, in the middle fingers of both hands of 10 healthy men. Finger vascular resistance was also estimated. The right hand was exposed for 7.5, 15, and 30 minutes (static load 10 N) to 125-Hz vibration (root-mean-square acceleration 87 m/s2). Static load only was used as a control. Finger circulation was measured before the vibration and static load exposure and at fixed intervals during exposure and a 45-minute recovery period.

Results No significant changes were found with the static load. The FST and FSBP did not change significantly during vibration exposure, whereas vibration produced significant reductions in FBF and increases in vascular resistance at each duration when compared with preexposure and contralateral (nonvibrated) finger values. Temporary vasodilation occurred in the vibrated finger immediately after each vibration exposure. Recovery was complete for FBF and vascular resistance after the 7.5-min vibration, whereas a progressive FBF reduction occurred in both the vibrated and the nonvibrated fingers during the second half of the recovery periods after 15- and 30-min exposure. The longer the duration of vibration exposure, the stronger the vasoconstriction in the vibrated finger during recovery.

Conclusion Vasoregulatory mechanisms mediated by both intrinsic (local) and extrinsic (neural or endocrine) control systems seem to be related to digital circulatory changes during 125-Hz vibration. These findings support previous investigations suggesting that, not only the frequency and magnitude of vibration, but also its duration contributes to the reaction of the digital vessels to acute vibration.

The following article refers to this text: 2006;32(5):383-391