title: Individual differences in the cortisol-awakening response during the first two years of shift work: A longitudinal study in novice police officers.
abstract: Cortisol acts as a critical biological intermediary through which chronic stressors like shift work impact upon multiple physiological, neuro-endocrine and hormonal functions. Therefore, the cortisol awakening response (CAR) is suggested as a prime index of shift work tolerance. Repeated assessments of the CAR (calculated as MnInc) in a group of 25 young novice police officers showed that in the interval between about 4 and 14 months after transitioning from regular day work to rotating shift work, mean values began to rise from baseline to significantly higher levels at about 14 months after they commenced shift work. Visual inspection of the individual trends revealed that a subgroup of 10 subjects followed a monotonically rising trend, whereas another 14 subjects, after an initial rise from about 4-14 months, reverted to a smaller, baseline level cortisol response at about 20 months after the start of shift work. If the initial increase in the cortisol response marks the development of a chronic stress response, the subsequent reversal to baseline levels in the subgroup of 14 participants might be indicative of a process of recovery, possibly the development of shift work tolerance.
authors: a Department of Psychology , University of Amsterdam , Amsterdam , The Netherlands and .
authors: Heidi M
authors: HM
authors: Lammers-van der Holst
authors: a Department of Psychology , University of Amsterdam , Amsterdam , The Netherlands and .|b Center for Sleep/Wake Disorders , MCH Westeinde Hospital, The Hague , The Netherlands.
authors: Gerard A
authors: GA
authors: Kerkhof
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D007206:Individuality; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016495:Police / Q000523:psychology; D012463:Saliva / Q000502:physiology; D013315:Stress, Psychological; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*; D014940:Work Schedule Tolerance / Q000502:physiology*; D055815:Young Adult
keywords: Cortisol awakening response; inter-individual variability; shift work tolerance; stress