[Blood pressure elevation among industrial workers exposed to stress].
A standardized, annual medical examination of a group of heat workers exposed to, and another group not exposed to heat in a Norwegian ferro-alloy plant over a period of six years showed no statistically significant difference in blood pressure between the two groups. However, following three years of stable blood pressure and heart rates, both parameters increased markedly in both groups. The occurrence of this sudden increase in blood pressure coincided with the plant being threatened with the possibility of closure due to inability to operate at a profit. This threat persisted for more than two years, but even afterwards, when it was quite clear that jobs at the plant were no longer threatened, the blood pressure remained markedly elevated. These findings emphasize the importance of being aware of the possible relationship between prolonged mental stress and hypertension.