TY - JOUR

T1 - Diurnal cortisol pattern of shift workers on a workday and a day off

AU - Karlson, Björn

AU - Eek, Frida Carlsson

AU - Hansen, Åsa Marie

AU - Garde, Anne Helene

AU - Österberg, Kai

AU - Øbæk, Palle

PY - 2006/11/21

Y1 - 2006/11/21

N2 - Objectives: The aim of this study was to determine how the diurnal rhythm of the hypothalamus-pituitary-adrenal axis is affected by a fast forward-rotating 24-hour shift schedule and to explore possible relationships with self-reported health, sleep-related problems, and recovery-related problems. Methods: Shift workers on their morning (N=45) or afternoon (N=32) shift were compared with daytime workers (N=39) from the same worksite and with an external daytime working reference group with early (N=50) or late (N=130) waking. Cortisol in saliva was sampled at waking, after 30 minutes, after 8 hours, and at 2100 on a daytime workday for all of the groups and also on a day off for the shift workers. Sleep and subjective health complaints were assessed with a questionnaire. Results: The morning shift workers showed a deviant cortisol pattern over the workday, with a lower cortisol level at waking and a lower morning peak level. The morning and afternoon shift workers did not differ with respect to the cortisol level on the day off. The shift workers also reported lower self-rated health and more problems with sleep and recovery. Conclusions: The results suggest that a partial adaptation of the circadian cortisol rhythm to night work does not re-adjust during 4 days off, and hence the early waking on morning shift days occurs during an earlier phase of the diurnal cortisol rhythm than for daytime workers waking up at similar hours. The results may contribute to the understanding of reduced alertness during morning shifts and have implications for the planning of, and adaptation to, shift schedules.

AB - Objectives: The aim of this study was to determine how the diurnal rhythm of the hypothalamus-pituitary-adrenal axis is affected by a fast forward-rotating 24-hour shift schedule and to explore possible relationships with self-reported health, sleep-related problems, and recovery-related problems. Methods: Shift workers on their morning (N=45) or afternoon (N=32) shift were compared with daytime workers (N=39) from the same worksite and with an external daytime working reference group with early (N=50) or late (N=130) waking. Cortisol in saliva was sampled at waking, after 30 minutes, after 8 hours, and at 2100 on a daytime workday for all of the groups and also on a day off for the shift workers. Sleep and subjective health complaints were assessed with a questionnaire. Results: The morning shift workers showed a deviant cortisol pattern over the workday, with a lower cortisol level at waking and a lower morning peak level. The morning and afternoon shift workers did not differ with respect to the cortisol level on the day off. The shift workers also reported lower self-rated health and more problems with sleep and recovery. Conclusions: The results suggest that a partial adaptation of the circadian cortisol rhythm to night work does not re-adjust during 4 days off, and hence the early waking on morning shift days occurs during an earlier phase of the diurnal cortisol rhythm than for daytime workers waking up at similar hours. The results may contribute to the understanding of reduced alertness during morning shifts and have implications for the planning of, and adaptation to, shift schedules.

KW - Karolinska Sleep Questionnaire

KW - Shift work

KW - Sleep

KW - Swedish occupational fatigue inventory

UR - http://www.scopus.com/inward/record.url?scp=33751022185&partnerID=8YFLogxK

M3 - Journal article

C2 - 17373256

AN - SCOPUS:33751022185

SP - 27

EP - 34

JO - Scandinavian Journal of Work, Environment & Health

JF - Scandinavian Journal of Work, Environment & Health

SN - 0355-3140

IS - 2

ER -