RESUMO
Background: There are incoherent studies about the effect of night shift work on circadian diurnal rhythms of cardiovascular parameters. Our study aimed to assess the alteration of circadian diurnal rhythms of cardiovascular parameters by night shift work. Methods: We studied 26 healthy nurse volunteers engaged in 3 shift work. From March 16 to April 30, 2006, ABPM (ambulatory blood pressure monitoring) was performed to each nurse two times during the day and night shift. Three nurses were excluded due to pain omdiced by ABPM. Blood pressure and heart rate was monitored every 30 minutes. Paired T-test was used for statistical analysis. Results: The mean arterial pressure, the mean systolic pressure, the mean heart rate and the mean pulse pressure during the overall period were significantly higher in the night shift than the day shift (P-value: <0.05, <0.001, <0.05, and <0.001, respectively). The mean arterial pressure, the mean diastolic pressure and the mean heart rate during in-hospital working period were significantly higher in the day shift (P-value: <0.05, <0.001, and <0.05, respectively). All parameters during the daytime sleep period after the night shift were significantly higher than during the nighttime sleep period after the day shift (P-values: <0.001). Proportional percentile falls of 3 parameters (systolic pressure, diastolic pressure, and heart rate) during the daytime sleep period after the night shift were significantly less than during the nighttime sleep period after the day shift (P-values: <0.001). Conclusion: The night shift work caused significant alteration in homeostasis of autonomic nervous system associated with circadian diurnal rhythms of cardiovascular parameters.
