On the Cardiovascular Effects of Whole‐Body Vibration Part II. Lateral Effects: Statistical Analysis

Abstract

Lateral vibrations of vessels generate relative lateral motions between red blood cells and plasma. These relative motions would cause additional transport of longitudinal momentum between different layers and therefore would increase the viscosity. Particularly for arterioles, which play the major role for the total peripheral resistance (TPR), the lateral vibration would destroy the cell‐free plasma layer near the wall if the local lateral amplitude of vibration were larger than 40 μm. Thus, if the local vibration gets stronger, one would expect TPR to increase if the vessels were not dilated. In order to test the possible dilations of vessels, a special design was made as follows. Three male subjects participated in this study. Each of them carried out a series of vibration tests on each of three vibrating devices. Accelerations at three locations on the body and various cardiovascular parameters were measured simultaneously. Each vibration test was divided into two or three parts with different body modes in a way that each change of body mode would increase the transmissibility and the local amplitudes. For the majority of changes of body mode, a decrease instead of an increase of TPR was observed. Statistical analysis (ANOVA Within Within) confirmed that the observed reduction of TPR during the changes of body mode was significant (p= 0.0235). This gives indirect but clear evidences for the dilation of vessels, particularly the dilation of arterioles. Since the dilation of vessels, particularly of arterioles, is an important ability of human body to prevent the blood pressure from getting too high during strong exercises, competitions and heavy physical work, the present study suggests a potential benefit, among others, of vibration training to improve this ability.