The Munich ChronoType Questionnaire for Shift-Workers (MCTQShift).

Area of Science:

• Chronobiology
• Occupational Health
• Sleep Medicine

Background:

• Chronotype influences sleep patterns in day-workers.
• Shift work poses challenges to sleep, health, and cognition.
• Accurate chronotype assessment is crucial for understanding shift-worker well-being.

Purpose of the Study:

• To validate an extended Munich ChronoType Questionnaire (MCTQ(Shift)) for shift-workers.
• To assess the feasibility of chronotype determination in shift-workers.
• To propose algorithms for chronotyping shift-workers, particularly those without free days after evening shifts.

Main Methods:

• Validation of MCTQ(Shift) using sleep logs (n=52) and actimetry (n=27).
• Evaluation of 371 MCTQ(Shift) entries from rotating 8-h shift-workers (0600, 1400, 2200 shifts).
• Analysis of sleep timing on free days and its relation to preceding shifts.

Main Results:

• MCTQ(Shift) validation confirmed its utility.
• Shift work makes sleep initiation and maintenance difficult.
• Shift-worker chronotype can be assessed using free-day mid-sleep time (MSF(E)), similar to day-workers.
• Free-day sleep times are stable but slightly influenced by prior shifts (<1h displacement).

Conclusions:

• The MCTQ(Shift) is a reliable tool for assessing chronotype in shift-workers.
• Chronotype assessment in shift-workers is feasible using specific sleep metrics.
• The findings support the need to consider chronotype in shift-work research and management.