The competition between SWS and REM sleep as index of maladaptation to shift work.

Polysomnographic and questionnaire investigation was performed in 22 train dispatchers and in 15 employees of post transportation during one work-rest cycle. In the group of subjects well adapted to the shift work, the slow-wave-sleep reached its peak duration in the day sleep and in the first recovery night, while REM rebound took place only on the second night. In maladapted subjects, REM sleep prevailed in the day sleep as well as in the first recovery night. The alteration of sleep structure can be thus used as a sign of adaptation vs maladaptation to shift work. Sleep structure of the recovery day sleep after single night sleep deprivation may be used as a prediction of adaptation to the shift work.