PSYCHOMOTOR AND CARDIOVASCULAR CONSEQUENCES OF MENTAL EFFORT AND NOISE

The effects of noise and mental workload on the psychomotor and cardio vascular systems were studied by monitoring the heart rate, systolic b lood pressure and electromyogram of subjects during effortful tasks in different situations. Registration of these variables provides an ins ight in the self-regulatory processes involved in short-term blood pre ssure regulation and motor control, caused by the accommodation of the body to situational changes. A rise in mental effort which was indica ted by cardiovascular and performance variables, was expected to cause muscle tension to increase. It appeared that tension in the neck and shoulder muscle was related to an increase in task difficulty. The int roduction of an external stressor (noise) had a main effect on the car diovascular and performance variables. This is in accordance with the hypothesis that subjects alter their state so that they can cope with noise, and maintain task performance. The interaction between noise an d two levels of task difficulty caused a significant additional (noise xdifficulty) change in the level of tension (in the task-specific musc les) but it had no (interaction) effect on the cardiovascular or perfo rmance variables. The relevance of the results for the relation betwee n mental effort on one side and getting backaches and neck and shoulde r pain on the other side is discussed.