Biological Rhythms Impact of 12 Hours Shift Work

Wake-sleep Cycle and Melatonin Secretion Dynamics Associated With 12 Hours Shift Work in French Nurses

Nonstandard time-schedules work are widespread in the world of work. Shift and night work have been shown to be responsible for a desynchronization of biological rhythms, associated with melatonin secretion impairment and sleep disturbances. However, while health consequences of night and shift work are widely recognized and represent a major public health concern (High Authority of Health 2012 Recommendations and National Agency for Public Health Food, Environment and Work 2016 Report), the mechanisms by which the circadian system is affected by shift work remain poorly understood. Indeed most of the studies in the fields are cross-sectional, based on few blood or urinary samples in a single work position, in workers whose shift work patterns are often misidentified and heterogeneous. Moreover, few studies have assessed melatonin secretion alterations in relation to objective sleep measurement (actigraphy). The aim of this study is to assess the dynamics of melatonin secretion adaptation in 12-hour shift work and to correlate these data to sleep-wake cycle recording.

Inclusion Criteria:

• Nurses or nursing assistants working in the Sleep and Respiratory Diseases Department of the Croix-Rousse Hospital with positions in 12 hours for more than 6 months
• informed consent given by the subject

Exclusion Criteria:

• Pregnancy or lactation <6 months
• Taking treatment modifying the secretion of melatonin (melatoninergic drugs (including antidepressants), beta-blockers)
• Refusal of participate
• Minor or major protected subject
• Not affiliated to a social security scheme
• Participant in another interventional study interfering with sleep / wake rhythm or work schedules (judgment of the investigator)