Cardiovascular responses of vibration-exposed workers to a cold provocation test.

Hemodynamic functions and changes in sympathetic nervous activity were assessed in 50 vibration-exposed workers without vibration-induced white finger (VWF), in 13 subjects with VWF, and in 41 referents. Indices of systolic time intervals such as the electromechanical systole index (QS2I) and the left ventricular ejection time index (LVETI) were found to be significantly shorter in the vibration workers than in the referents both at rest and during a cold provocation test. A significant inverse relationship between urinary levels of free catecholamines and the duration of the LVETI was observed under resting conditions. The recovery rate of the basal finger skin temperature after cold provocation was slower in the vibration-exposed workers than in the referents. The indices of platelet aggregation were about the same in all the groups studied. The results of this investigation suggest that cardiac sympathetic tone and digital vascular reactivity to cold are increased in vibration-exposed workers.