Abstract
The evaluation of vibration exposure has had three aims for the prevention of vibration syndrome among Japanese forest workers using chain saws and bush cutters. The first was to introduce exposure time regulation in chain saw and bush cutter operation, the second to improve the chain saw and bush cutter, and the third to find effective tests for the early diagnosis of vibration syndrome. For the first aim, correlations between vibration exposure time (minutes, hours, days and years) and physiological effects including subjective symptoms were observed. From the results, new effective regulations were introduced. For the second aim, existing and new chainsaws and bush cutters were compared in terms of vibration acceleration level and changes of physiological function between before and after chain saw and bush cutter operation. Those results promoted the improvement of chain saws and bush cutters. For the third aim, correlations between vibration exposure dose and physical examination results were analyzed. From the analysis, effective tests relating closely with vibration exposure dose were obtained.
