Industrial Health 2012, 50, 24–30
Recovery after Three-shift Work: Relation to
Sleep-related Cardiac Neuronal Regulation
Min-Huey CHUNG1, Terry B. J. KUO2, 3, Nanly HSU4, Hsin CHU5,
Kuei-Ru CHOU1 and Cheryl C. H. YANG2, 3*
1 Graduate Institute of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan
2 Institute of Brain Science, National Yang-Ming University, No. 155, Sec. 2, Linong St., Beitou Dist., Taipei City
3 Sleep Research Center, National Yang-Ming University, No. 155, Sec. 2, Linong St., Beitou Dist., Taipei City,
4 Department of Nursing, Yuanpei University, No. 306, Yuanpei St., Xiangshan Dist., Hsinchu City, Taiwan
5 Institute of Aerospace Medicine, School of Medicine, National Defense Medical Center, Taipei, Taiwan
Received May 20, 2011 and accepted November 8, 2011
Published online in J-STAGE December 6, 2011
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. Sleep-
related autonomic functions may be improved during days off to minimize health risks.
Key words: Nurses, Sleep, Autonomic nervous system, Heart rate variability, Shift work
Nurses working rotating three-shifts may work in the
morning, afternoon, or night. Working different shifts
interrupts their daily schedules significantly, with those
working night shifts requiring sleep during the daytime.
*To whom correspondence should be addressed.
©2012 National Institute of Occupational Safety and Health
M-H CHUNG et al.
Industrial Health 2012, 50, 24–30
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