Duration of acute exposures to vibration and finger circulation

Abstract

Objectives This study investigated changes in finger circulation after different durations of exposure to handtransmitted vibration. Methods Finger skin temperature (FST), finger blood flow (FBF), and finger systolic blood pressure (FSBP) were measured 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 (rootmean-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-minute vibration, whereas a progressive FBF reduction occurred in both the vibrated and the nonvibrated fingers after 15-and 30-minute exposure. The longer the duration of vibration exposure, the stronger the vasoconstriction in the vibrated finger during recovery. C O~C~U S~O N SVasoregulatory 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. It is concluded that, not only the frequency and magnitude of vibration, but also its duration contributes to the reaction of the digital vessels to acute vibration.

Acute response of finger circulation to force and vibration applied to the palm of the hand

“…Furthermore, after the cessation of vibration and force, it cannot be assumed that the complex systems controlling blood flow will instantly return to their state before the application of vibration and force. As seen in this study and also previously (10)(11)(12)(13), there can be after-effects as the vascular system recovers. Further study is needed to uncover the responsible mechanisms and understand their influences.…”

“…We have previously reported acute changes in finger blood flow produced by laboratory exposures of fingers to vibration and systematically explored how reductions in the flow depend on the frequency, magnitude, and duration of exposure (9)(10)(11)(12). We have also reported the effects of various combinations of finger push force (no force, 2 N or 5 N) and vibration [31.5 Hz at 4 and 16 m/s 2 root mean square (rms) and 125 Hz at 16 and 64 m/s 2 rms] on finger blood flow in an exposed right middle finger, an unexposed right little finger, and an unexposed left middle finger (13).…”

Relation between vibrotactile perception thresholds and reductions in finger blood flow induced by vibration of the hand at frequencies in the range 8–250 Hz

“…Finger blood flow after the cessation of vibration depends on the frequency of vibration, the magnitude of vibration, and the duration of exposure to vibration (Bovenzi et al, 1998(Bovenzi et al, , 1999. With the same frequency-weighted acceleration at both frequencies, a stronger vascular after-effect of vibration (i.e., less finger blood flow and longer recovery period) has been reported after exposure to 125-Hz vibration than after exposure to 16-Hz vibration .…”

“…There are also acute effects of hand-transmitted vibration in which finger blood flow is reduced during and immediately after exposure to vibration, with reductions occurring on the hand exposed to vibration and on the contralateral hand not exposed to vibration (Bovenzi et al, 1998(Bovenzi et al, , 1999. It is not yet understood why vibration affects digital circulation or which mechanisms are involved in the dis-regulation of circulation.…”

A New Method for the Experimental Assessment of Finger Haemodynamic Effects Induced by a Hydraulic Breaker in Operative Conditions

“…The findings of experimental investigations of both normal subjects and patients with VWF suggest that the reduction in finger blood flow, finger skin temperature and finger blood pressure may depend on the frequency, magnitude and duration of the vibration stimulus [2][3][4][5][6] . All such factors thus need to be taken into account when assessing the probability of adverse effects in the digital vessels 7) .…”