Blood flow in the contralateral hand during vibration and hand grip contractions of lumberjacks.

Pulse wave changes were examined among 63 professional lumberjacks. The tests were carried out in connection with an annual health examination. A photoelectric plethysmographic method was used to measure pulse wave changes during contralateral muscle work and vibration exposure from a dynamic shaker with a strain-gauge dynamometer. The relative changes in pulse wave amplitude were counted, and the changes were classified as dilatations, constrictions, or constant pulse wave amplitude. Contralateral muscle work caused vasodilatation, but vibration exposure could cause vasoconstrictions in the right hand. Most of the vasospasms were recorded at 60 and 100 Hz. The strongest vasospasms were seen at 200 Hz. The occurrence of vasospasms in the contralateral hand correlated with the severity of white finger symptoms rated according to an index for traumatic vasospastic disease.