Plasma catecholamines and pituitary adrenal hormones related to mental task demand under quiet and noise conditions.

Plasma levels of catecholamines and pituitary adrenal hormones were measured in 20 min samples from eight subjects, in one control session and two experimental sessions, while they performed a short-term memory task under quiet of noise conditions. Performing the task led to significant increase in the plasma levels of cortisol, adrenaline and noradrenaline, whereas no variations in growth hormone and dopamine were observed. Similarly, significant changes occurred in urinary catecholamine excretion. A significant correlation was found between individual plasma cortisol increments and error-rates assessed from an accuracy of recall variable. For adrenaline and noradrenaline, an early response apparently linked with an anticipatory process preceded the task. Exposure to noise did slightly amplify cortisol response to the task, but during the first experimental session, with or without noise, the task elicited greater cortisol increases in all subjects than during the second session. These results provide evidence for a relationship between sympathoadrenocortical activity and attentional demand, whereas cortisol increments seem to be more specifically related to better coping with the task. Frequent hormone level measurements during a prolonged mental task might clarify the complex relationship between time-related bodily hormonal changes, performance and subjective feelings.