PSYCHOMOTOR AND CARDIOVASCULAR CONSEQUENCES OF MENTAL EFFORT AND NOISE

The effects of noise and mental workload on the psychomotor and cardiovascular systems were studied by monitoring the heart rate, systolic blood pressure and electromyogram of subjects during effortful tasks in different situations. Registration of these variables provides an insight in the self-regulatory processes involved in short-term blood pressure regulation and motor control, caused by the accommodation of the body to situational changes. A rise in mental effort which was indicated 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 introduction of an external stressor (noise) had a main effect on the cardiovascular 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 and two levels of task difficulty caused a significant additional (noisexdifficulty) change in the level of tension (in the task-specific muscles) but it had no (interaction) effect on the cardiovascular or performance variables. The relevance of the results for the relation between mental effort on one side and getting backaches and neck and shoulder pain on the other side is discussed.