Get full text report (pdf file; Read by ADOBE Acrobat Reader)
J Occup Health year 2008 volume 50 number 5 page 380 - 386
Classification Originals
Title Elevated Blood Pressure, Decreased Heart Rate Variability and Incomplete Blood Pressure Recovery after a 12-hour Night Shift Work 
Author Ta-Chen SU1-3, Lian-Yu LIN1, Dean BAKER4, Peter L. SCHNALL4, Ming-Fong CHEN1, Wen-Chang HWANG3, Chen-Fang CHEN3 and Jung-Der WANG1-3
Organization 1Department of Internal Medicine, 2Department of Environmental and Occupational Medicine, National Taiwan University Hospital, 3Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taiwan and 4Center for Occupational and Environmental Health, University of California at Irvine, USA
Keywords Blood pressure, Heart rate variability, 12-hour night shift work, Delayed recovery
Correspondence J.-D. Wang, College of Public Health, National Taiwan University, Rm. 719, No. 17, Xu-Zhou Road, Taipei 10020, Taiwan (e-mail: jdwang@ntu.edu.tw)
Abstract Elevated Blood Pressure, Decreased Heart Rate Variability and Incomplete Blood Pressure Recovery after a 12-hour Night Shift Work: Ta-Chen SU, et al. Department of Internal Medicine, National Taiwan University Hospital, Taiwan-Shift work has been associated with increased risk of cardiovascular disease. This study was designed to determine the hemodynamic effects of 12-hour (12-h) shifts, and changes in blood pressure (BP) and heart rate variability (HRV) during 36 h rest time following 12-h shifts. Fifteen male shift workers with a mean age of 32.9 yr were recruited from a semiconductor factory. Ambulatory BP (AmBP) monitoring was performed for a total of 48 h for each participant. Six workers were monitored for 48 h by Holter electrocardiogram on both the day and night shifts. Paired self-comparison was used to estimate the difference between two hourly measurements of 12-h BP, HR, and HRV using the same timetable intra-individually. We also applied mixed models to estimate the effects of 12-h shifts on the delayed recovery of BP and heart rate (HR) in six workers who completed 96-h AmBP monitoring, including a 48-h night shift-rest period and another day shift period. Results showed that 12-h night shift work gave a persistently elevated systolic and diastolic BP (SBP and DBP) and HR, and decreased HRV compared to 12-h day shift work with the corresponding resting time. In addition, there was delayed SBP and DBP recovery on the first 12-h rest time in night shift workers, which was further demonstrated on the second 12-h rest time after adjustment for possible confounders through mixed models. In conclusion, 12-h night shift work may elevate BP and HR and decrease HRV. It is also associated with delayed BP recovery.