Effects of implementing an ergonomic work schedule on heart rate variability in shift-working nurses.

OBJECTIVES: The aim of this study was to compare the psychophysiological strain related to a conventional shift schedule and new ergonomically improved two- and three-shift schedules using heart rate variability (HRV) analysis. The specific aim was to determine whether the introduced ergonomic shift arrangement had any positive effects on the psychophysiological strain such as increased HRV or decrease in the sympathovagal balance of the autonomic nervous system (ANS). METHODS: Questionnaire data and 24-hour HRV recordings were gathered from 48 female shift-working nurses once while working the conventional shift schedule (baseline) and again after one year working an ergonomic shift schedule during the morning shift. RESULTS: Comparisons between conventional and ergonomic shift schedules (baseline and follow-up, respectively) revealed significant differences in frequency-domain parameters. Implementing an ergonomic shift schedule resulted in decreased normalized low frequency (LF) power, increased normalized high frequency (HF) power, and decreased LF/HF ratio at the beginning of the shift. Furthermore, at baseline, mean RR interval, root mean square of successive RR interval differences (RMSSD) and normalized HF power were increased at the end of the shift compared with the values at the beginning of the morning shift. In contrast, at the follow-up, LF power was increased between the end and beginning of the morning shift. CONCLUSIONS: The psychophysiological strain measured by HRV analysis was lower at the beginning of the work shift for the ergonomic shift schedules compared with the conventional schedule. This indicates that an ergonomic shift schedule may have a positive effect on the ANS recovery occurring between successive work shifts.

Less quick returns--greater well-being.

The aim of this study was to design ergonomically improved shift schedules for nurses in primary health care shift work in order to enhance their health and well-being. The main change made was the reduction of quick returns (i.e., no more morning shifts immediately after an evening shift) in order to ensure more recovery time between work shifts. Six municipal hospital units participated in the intervention. Our aim was to maintain or improve the well-being and work ability of aged workers. The subjects (n=75) were divided into three age groups: 20-40, 41-52, and 53-62 yr. The introduction of more recovery time between evening and morning shifts significantly improved the subjects' sleep and alertness, well-being at work, perceived health, and leisure-time activities independently of their age. The effect on social and family life was also positive. Working in shifts was the most disruptive for the youngest group of nurses. The Work Ability Index score depended on the age group: it was lowest among the oldest age group, and did not change during the intervention. Ergonomic working time arrangements show positive effects on the well-being of health care workers of all ages.