Exhaustion measured by the SF-36 vitality scale is associated with a flattened diurnal cortisol profile

The possible association between stress-related exhaustion and reduced activity in the hypothalamo-pituitary-adrenal (HPA) axis is increasingly in focus. The aim of the present study was to examine whether exhaustion measured in a non-patient population is associated with alterations in diurnal cortisol profile. The study population included 78 working individuals. The study group was dichotomised into exhausted and non-exhausted groups by means of the SF-36 vitality scale. Salivary cortisol was measured at three times during 1 workday: at awakening, 30min after awakening, and in the evening. The results showed that diurnal cortisol variation was significantly reduced in exhausted individuals. The difference in cortisol variation was mainly due to lowered morning cortisol in the exhausted group. Differences in cortisol levels at each sampling time or in mean diurnal output of cortisol were not statistically significant. The results would support the notion that exhaustion is associated with HPA axis hypoactivity as assessed by salivary cortisol. Furthermore, the SF-36 vitality provides a measure of exhaustion that may be useful in epidemiological studies in order to explore long-term health effects of stress-related exhaustion.