engleski

The effects of shift work on nonlinear aspects of cardiovascular dynamics

Since shift work is considered as s risk factor for health problems due to the continuous desynchronization and resynchronization of circadian rhythms, the aim of this study was to determine whether shift work (and different length of this work) affects nonlinear aspects of cardiovascular dynamics in healthy shift workers. The study included 48 nurses divided in two groups (24 nurses in each) of equal age and length of service. One group worked in a three-shift rotation system and the other (control) worked only the day shift. On the basis of length of service, the groups were divided into three comparable subgroups with eight participants: 1–10, 11–20 and 21–30 years of service. Cardiac activity (R-R intervals) was monitored continuously during sleep using the Data Logging System. Results showed that shift workers with up to 10 years of service had higher values of correlation dimension than the equivalent group of day workers, but shift workers with more than 10 years of service had lower values of correlation dimension than comparable groups of day workers. All shift workers, regardless of length of service, had significantly higher indexes of determinism than day workers, but index of determinism slightly enlarge with increase of years of services. Generally, it seems that shift work has a negative impact on cardiovascular dynamics from very beginning, and nonlinear parameters of cardiovascular dynamics can be potential predictors of health problems in the future.

shift work, cardiovascular dynamics, R-R interval, index of determinism, correlation dimension

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