Salivary cortisol patterns in vital exhaustion

The syndrome of vital exhaustion (VE), a risk indicator for myocardial infarction, is characterized by excessive fatigue, irritability, and demoralization. Dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) axis is a potential pathogenic mechanism in fatigue syndromes, but little is known about HPA function in syndromal VE.

We assessed basal free cortisol levels and responses to a speech task and to morning awakening by collecting multiple saliva samples over 2 days from 29 VE men and 30 controls.

VE subjects reported higher perceived stress, poorer sleep, and greater fatigue than controls. Basal cortisol levels were lower in VE subjects, especially in the evening, and were negatively associated with fatigue. Overall cortisol responses to the speech task were similar in VE and control groups, although VE subjects were less likely to show large (> or =2.76 nmol/l) responses. The cortisol response to awakening was associated with concurrent fatigue and poor sleep quality.

These findings suggest a subtle HPA hypoactivity in VE, which may arise through chronic stress and associated sleep disturbances.