In order to study the effects of static force such as a handgrip in detail, the peripheral circulatory function and the autonomic nervous function of workers who used chain-saws were examined in a handgrip test at 30% of maximum voluntary contraction (30% MVC). Workers using chain-saws were divided into three groups: group A without any symptoms, group B with numbness and/or pain but without Raynaud's phenomenon and group C with Raynaud's phenomenon.
The results obtained were as follows:
1. The finger blood flow (FBF) of all groups significantly decreased during the handgrip and significantly increased after the end of the handgrip as compared with the initial value. There was a tendency for the FBF decrease of group C to be less than that of group A.
2. The mean value of both maximum FBF decrease and maximum FBF increase during handgrip tests fell in alphabetical order (A, B, C). The maximum FBF increase of group C was significantly less than that of group A.
3. The finger skin temperature (FST) of each group significantly fell during the handgrip but there was no significant difference among the three groups. FST returned to the level of the initial value one minute after the end of the handgrip, and significantly rose two minutes and three minutes after the end of the handgrip as compared with the initial value.
4. Both the systolic blood pressure and the diastolic blood pressure of all groups significantly rose during the handgrip but there was no significant difference among the three groups. Concerning the maximum rise of diastolic blood pressure, which is an indicator of autonomic nervous function, there was no significant difference among the three groups.
It was concluded that observation of FBF, which is an indicator of peripheral circulatory function, in the handgrip test at 30% MVC was useful not only in the assessment of the peripheral circulatory function of workers with Raynaud's phenomenon in the period without attack of Raynaud's phenomenon but also for early diagnosis of peripheral circulatory disorders in workers without Raynaud's phenomenon.
