AbstractsMedical & Health Science

Association of job strain with sleep and psychophysiological recovery in shift working health care professionals

by Kati Karhula

Institution: University of Helsinki
Department: Institute of Behavioural Sciences; Finnish Institute of Occupational Health
Year: 2015
Keywords: psykologia
Record ID: 1141280
Full text PDF: http://hdl.handle.net/10138/153231


Health care personnel often have irregular working hours and stressful work characteristics, which may challenge employees possibilities to sleep and recover sufficiently. The aim of this study was to examine the association of stressful work characteristics, measured as job strain, with sleep and psychophysiological recovery in shift working health care professionals. As part of the Finnish Public Sector Study, 95 participants were recruited from hospital wards that belonged to the top (high job strain, HJS, n=42) or bottom quartiles on job strain (low job strain, LJS, n=53) as determined by the average job strain score among the employees of the ward. These participants experienced job strain at least as high (HJS group) or as low (LJS group) as the average on their ward. Measurements included a Trier Social Stress Test (TSST), and 3-week field measures of sleep-wake rhythm with sleep diary and actigraphy. The 3-week rosters included three pre-selected, circadian rhythm and recovery controlled measurement days, one morning shift, one night shift and a day off, and the following measurements: ratings of sleepiness (Karolinska Sleepiness Scale), Psychomotor Vigilance Test (PVT), 24h heart rate variability (HRV) measurements and saliva samples of stress biomarkers (cortisol and alpha-amylase). The rosters of the HJS group included more single days off and quick returns than the rosters of the LJS group. Severe sleepiness (KSS score of ≥7) was more common in the HJS group in quick returns. The HJS group reported poorer recovery from all work shifts and after morning shifts than the LJS group. High job strain was not associated with extended working hours. The HJS group had more difficulties in initiating sleep after evening shifts, more often reduced sleep efficiency before morning shifts, and took fewer and shorter naps before the first night shift than the LJS group. Additionally, the HJS group had more often lapses in the PVT during night shifts. Insufficient sleep (31%) and sleep complaints (often 68%) were common in shift workers regardless of the job strain group. The TSST resulted in, on average, a 2.27-fold increase in cortisol concentration in the HJS group and a 1.48-fold increase in the LJS group (non-significant group difference). The HJS group also had higher salivary alpha-amylase levels 30 minutes after awakening in the morning shift. Apart from that, the salivary cortisol and alpha-amylase levels, profiles and total secretion showed no statistically significant stress group differences. Heart rate and HRV, before and during sleep, were similar in both job strain groups. Shift work contributed to impaired sleep in both the high and low job strain groups, although the sleep impairments were more pronounced in the HJS group. Associations between job strain and psychophysiological stress-related reactions and recovery were modest. Intervention studies are needed to determine whether increasing recovery time by reducing the number of quick returns and single days off would also reduce job strain and…