Effect of vibration frequency on finger blood flow

Abstract

A total of 18 healthy subjects (9 men and 9 women) 20-35 years of age were used to study the effect of vibration frequency on finger blood flow. Seven vibration frequencies of 16, 31.5, 63, 125, 250, 500 and 1,000 Hz, at vibrational accelerations of 10 m/s2 (rms: root mean square) or 50 m/s2 (rms), with the exception of 16 Hz, which was measured at only 10 m/s2 (rms), were randomly applied to the palm of the right hand for 1 min at intervals of about 3 min. Finger blood flow was measured simultaneously in both the right and the left middle fingers with a blood flowmeter using a thermal diffusion method and in the left middle finger with a laser Doppler flowmeter. The experiments were performed in an artificial climate chamber set at 23 degrees C air temperature and 50% humidity. Relatively great responses were observed at frequencies of 31.5-63 and 250-500 Hz on the exposed and unexposed sides, respectively, as measured with a blood flowmeter using a thermal diffusion method and at 31.5-63 as well as 500 Hz on the unexposed side with a laser Doppler flowmeter. These results may be related to Meissner's and pacinian corpuscles.

Study of the biodynamic response of the foot to vibration exposure

“…Second, although participants' foot placement was controlled and all were given the same instruction with regard to how to stand, it could not be confirmed that all participants' maintained the same posture throughout the 45-second FTV exposure period. Deviations in posture can influence vibration transmissibility due to changes in the surface contact area with the vibrating surface, which can influence the position of the bony structures and the degree of tension in different muscle groups of the trunk and the extremities, in turn changing the resonant frequency of the body structure [1,19,21,25,36,[38][39][40][41]. Thus, variations in the ankle and knee angles could have influenced the transmission of vibration from the platform through the feet and into the lower limbs.…”

“…Confirming the resonant frequencies at different locations on the foot will help determine exposure frequencies that are most likely to lead to health risks [41] in workers exposed to FTV. A greater understanding of the transmissibility properties of the foot is also needed to design controls such as isolation platforms, anti-vibration drills, and personal protective equipment such as mats and insoles for workers exposed to FTV [42].…”

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

“…This assumption underlies frequency weighting W h , used to predict the severity of hand-transmitted vibration (ISO 5349-1, 2001). Laboratory studies of acute responses to hand-transmitted vibration have found that with the same frequencyweighted acceleration at all frequencies there is more vasoconstriction in the fingers (on both the exposed hand and the unexposed hand) with frequencies greater than 30 Hz than with lower frequencies (Furuta et al, 1991;Bovenzi et al, 2000;Thompson and Griffin, 2009). …”

Evidence for frequency-dependent arterial damage in vibrated rat tails

“…The disease is characterized by nervous, musculoskeletal, and vascular (white finger vasospasm) debilitating deficits in the upper extremities (Cherniack, 1990;Noel, 2000). Studies of HAVS and animal models of vibration exposure suggest that injury may be vibration frequency (Hz)-dependent, although the findings are contradictory (Hyvarinen et al, 1973;Okada, 1986;Furuta et al, 1991;Bovenzi et al, 2000). While vibrating tools emit complex waveforms of amplitude, direction, and fre-frequency (Radwin et al, 1990;Hutton et al, 1993).…”