Recovery after Three-shift Work: Relation to Sleep-related Cardiac Neuronal Regulation in Nurses

Abstract

This study was to evaluate whether sleep-related autonomic function in nurses recovers during their days off following a rapidly rotating, clockwise shift schedule. Ten rotating-shift nurses and ten regular morning-shift nurses were included. Nurses slept at home and were allowed to sleep and wake spontaneously. For the rotating-shift workers, ambulatory polysomnographic recordings were taken during nighttime sleep (after the second morning shift, afternoon shift, and on days off) and during daytime sleep (after the second night shift). No significant differences were found between regular-shift nurses and rotating-shift nurses in terms of sleep patterns and cardiac autonomic functions during day shift. When comparing sleep patterns within shift groups, the total sleep time of night shift was lower than their other shifts. Controlling for the variable of total sleep time allowed us to compare cardiac autonomic functions following different shifts (for the rotating shift nurses). During the non-rapid eye movement and rapid eye movement periods, the high frequency (HF) value on rotating shift nurses' days off was found to be significantly higher than their other shifts. However, the low to high frequency ratio (LF/HF) on days off was found to be obviously lower than that during shift work. Two consecutive days off may be sufficient for nurses to recover sleep-related autonomic functions after a rapidly rotating, clockwise three-shift schedule. Sleeprelated autonomic functions may be improved during days off to minimize health risks.

Job strain and vagal recovery during sleep in shift working health care professionals

“…On the other hand, the high frequency (HF) HRV power values of rotating shift nurses on days off were found to be significantly higher than on their shifts (Chung et al, 2012). Also, the LF/HF ratio on days off was found to be lower than that during shift work (Chung et al, 2012). Noticeably, HRV profiles usually return to the baseline level after each shift (Lo et al, 2010).…”

“…When female nurses and caregivers in regular day work and shift work were compared on a day shift, no significant differences in 24-h ambulatory HRV were found (Yoshizaki et al, 2013). On the other hand, the high frequency (HF) HRV power values of rotating shift nurses on days off were found to be significantly higher than on their shifts (Chung et al, 2012). Also, the LF/HF ratio on days off was found to be lower than that during shift work (Chung et al, 2012).…”

“…In a recent study (Lin et al, 2013), among medical interns, even extremely long working hours during 1 year did not present changes in female physicians' HRV. In a shift working nurse study (Chung et al, 2012), no significant differences were found between regular-shift nurses and rotating-shift nurses in terms of sleep patterns and cardiac autonomic functions during day shift. In another nurse study (Riese et al, 2004), HRV was not associated with work strain in a homogenous group of night shift workers.…”

“…The confidence intervals make it possible to study the stability of the individual measures and allow parameters to be compared between groups. Despite data of the same size or even smaller data, many of the earlier studies (Chung et al, 2012;Hernandez-Gaytan et al, 2013;Järvelin-Pasanen et al, 2013;Lo et al, 2010;Ritvanen et al, 2006) have not used bootstrapping, which is especially well suited for samples of limited size.…”

“…However, in our previous study (Karhula et al, 2013), we found associations with high job strain and too high perceived workload and poor inter-shift recovery. There is evidence, that 2 consecutive days off may be sufficient for nurses to recover sleep-related autonomic functions after a rapidly rotating, clockwise three-shift schedule (Chung et al, 2012). ANS recovery from high perceived job strain has been found to be insufficient especially among older female employees (Ritvanen et al, 2006).…”