In:
Journal of Biological Rhythms, SAGE Publications, Vol. 28, No. 2 ( 2013-04), p. 130-140
Abstract:
Sleep is systematically modulated by chronotype in day-workers. Therefore, investigations into how shift-work affects sleep, health, and cognition may provide more reliable insights if they consider individual circadian time (chronotype). The Munich ChronoType Questionnaire (MCTQ) is a useful tool for determining chronotype. It assesses chronotype based on sleep behavior, specifically on the local time of mid-sleep on free days corrected for sleep debt accumulated over the workweek (MSF sc ). Because the original MCTQ addresses people working standard hours, we developed an extended version that accommodates shift-work (MCTQ Shift ). We first present the validation of this new version with daily sleep logs ( n = 52) and actimetry ( n = 27). Next, we evaluated 371 MCTQ Shift entries of shift-workers (rotating through 8-h shifts starting at 0600 h, 1400 h, and 2200 h). Our results support experimental findings showing that sleep is difficult to initiate and to maintain under the constraints of shift-work. Sleep times are remarkably stable on free days (on average between midnight and 0900 h), so that chronotype of shift-workers can be assessed by means of MSF—similar to that of day-workers. Sleep times on free-days are, however, slightly influenced by the preceding shift (displacements 〈 1 h), which are smallest after evening shifts. We therefore chose this shift-specific mid-sleep time (MSF E ) to assess chronotype in shift-workers. The distribution of MSF E in our sample is identical to that of MSF in day-workers. We propose conversion algorithms for chronotyping shift-workers whose schedules do not include free days after evening shifts.
Type of Medium:
Online Resource
ISSN:
0748-7304
,
1552-4531
DOI:
10.1177/0748730412475041
Language:
English
Publisher:
SAGE Publications
Publication Date:
2013
detail.hit.zdb_id:
2018064-0
SSG:
12
