Mental task-induced strain and its after-effect assessed through variations in plasma cortisol levels

Plasma cortisol levels were measured in 20 healthy men while they carried out mental tasks in intermittent noise. Half the subjects performed a serial short-term memory task and, later on, a multiple-choice task, whereas the other half performed only the multiple-choice task. The aim of the experiment was to determine whether enhanced cortisol release, due to a centrally mediated arousal reaction, depressed the cortisol level when the subjects had to cope with a new task situation. In a previous study, such a regulatory after-effect was revealed in the midday meal-related cortisol peak, but not in a subsequent exercise-induced cortisol peak, although cortisol release in both cases could be related to metabolic changes. The results showed that the second mental task still induced a pronounced rise in cortisol levels. No changes in task performances were found. It is concluded that different regulatory mechanisms are involved in adrenocortical secretion, depending on the origin of the stimulation, and that cortisol responses are closely related to individual coping abilities and strategies.