Elevated salivary cortisol levels as a result of sleep deprivation in a shift worker

BACKGROUND: This paper reports a case from a group of 63 shift-workers for whom adaptation to shift-work was evaluated through measurement of salivary cortisol levels. METHODS: Workers' saliva was sampled and cortisol levels measured at intervals of 2 h during morning, evening and night shifts. RESULTS: For one subject among the 63, very high values of cortisol (an approximately 6-fold increase) were observed for the morning (M) shift, but with normal values found for evening (E) and night (N) shifts. Individual mean and peak cortisol values were 48.4 and 67.8 nmol/l against group mean and peak cortisol values of 8.9 and 11.0 nmol/l. Retrospective questioning showed that this subject was healthy and there were no indicators of long-term stress. CONCLUSION: This cortisol rise was deduced to be caused by sleep deprivation as a result of rapidly rotating shift patterns.