Responses of workers exposed to vibration in autonomic nervous function tests.

Heart rate variation in quiet breathing and deep breathing tests and the response of blood pressure in a cold pressor test were measured in 34 railway workers and 13 lumberjacks. The age-adjusted results showed a significant relationship between exposure to hand-arm vibration and the coefficient of beat-to-beat variation in the quiet breathing test (CVS) in the railway workers. The vibration-induced white finger (VWF) and non-VWF subjects showed non-significant differences in respect of all the indices used. This investigation, in common with previous results, suggests that vibration might cause changes in cardiovascular reflexes, but the indices used here seem to be of low sensitivity, at least partially due to wide physiological variation; other more suitable indicators and studies of the pathophysiological background of the suspected effect are needed to confirm the results.