title: Elevated blood pressure, decreased heart rate variability and incomplete blood pressure recovery after a 12-hour night shift work.
abstract: 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.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taiwan.
authors.forename: Ta-Chen
authors.initials: TC
authors.lastname: Su
authors.forename: Lian-Yu
authors.initials: LY
authors.lastname: Lin
authors.forename: Dean
authors.initials: D
authors.lastname: Baker
authors.forename: Peter L
authors.initials: PL
authors.lastname: Schnall
authors.forename: Ming-Fong
authors.initials: MF
authors.lastname: Chen
authors.forename: Wen-Chang
authors.initials: WC
authors.lastname: Hwang
authors.forename: Chen-Fang
authors.initials: CF
authors.lastname: Chen
authors.forename: Jung-Der
authors.initials: JD
authors.lastname: Wang
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D015716:Electrocardiography, Ambulatory; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007221:Industry; D008297:Male; D010561:Personnel Staffing and Scheduling; D012146:Rest / Q000502:physiology; D012892:Sleep Deprivation / Q000503:physiopathology; D013624:Taiwan; D013997:Time Factors; D014940:Work Schedule Tolerance / Q000502:physiology*