Objectives: The objective of the present study was to investigate the effects of rotating night shift and light exposure at night on circadian pattern of salivary cortisol and urinary melatonin levels. Methods: 62 healthy nursing professionals of both genders performing day and night shifts (continuous 9 days night shift with alternate day shifts) were recruited. Each month scheduled to continu...

Shift work has become an integral part of our life with almost 20% of the population being involved in different shift schedules in developed countries. However, the atypical work times, especially the night shifts, are associated with reduced quality and quantity of sleep that leads to increase of sleepiness often culminating in accidents. It has been demonstrated that shift workers' sleepines...

School system in which classes are scheduled 1 week in the morning and the other in the afternoon, and in which students rotate schedule every week, fosters sleep irregularity. In this study, we examined morningness-eveningness of adolescents who were involved in such schedule of school time and explored relationship between their circadian preferences and sleep characteristics. A large sample ...

Background: Shift work is highly prevalent in industrialized societies. Work hours that displace sleep to the daytime and work to the night time will interfere with the circadian and homeostatic regulation of sleep. Such work hours has pronounced negative effects on sleep, subjective and physiological sleepiness, performance, accident risk as well as on health outcomes.Work hours that displace ...

BACKGROUND To assess the effects of isolation, inadequate exposure to light and specific shift work on the subjective and objective measurements of sleep and alertness of submariners. PURPOSE A strictly controlled randomized crossover study with the polysomnography recorded twice during the mission. METHODS Setting: Shift and night work with prolonged (70 days) social isolation from the rea...